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iot.stackexchange.com

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2017-01-04T19:23:14.037

<p>The Coke Machine, rather amusingly, <a href="https://www.cs.cmu.edu/~coke/">has its own website</a> with a bit more information on its history.</p> <p>The <a href="https://www.cs.cmu.edu/~coke/history_long.txt"><em>Ancient History</em></a> document explains how the original Coke Machine operated:</p> <blockquote> <p>The final piece of the puzzle was needed to let people check Coke status when they were logged in on some other machine than CMUA. CMUA's Finger server was modified to run the Coke status program whenever someone fingered the nonexistent user "coke". (For the uninitiated, Finger normally reports whether a specified user is logged in, and if so where.) Since Finger requests are part of standard ARPANET (now Internet) protocols, people could check the Coke machine from any CMU computer by saying "finger coke@cmua". In fact, you could discover the Coke machine's status from any machine anywhere on the Internet! Not that it would do you much good if you were a few thousand miles away...</p> </blockquote> <p>For the first generation Coke Machine, in the 70s and 80s, the <code>finger</code> command was (ab)used while connecting through <a href="https://en.wikipedia.org/wiki/ARPANET">ARPANET</a>, the precursor of the Internet. Not exactly a complex protocol, but it worked well enough to indicate the state of the coke machine without being overly difficult to set up.</p> <p>If you're interested in <em>exactly</em> how the <a href="https://en.wikipedia.org/wiki/Finger_protocol"><code>finger</code> command</a> worked, here is an extract from Wikipedia detailing how it operates:</p> <blockquote> <p>The finger daemon runs on TCP port 79. The client will (in the case of remote hosts) open a connection to port 79. An RUIP (Remote User Information Program) is started on the remote end of the connection to process the request. The local host sends the RUIP one line query based upon the Finger query specification, and waits for the RUIP to respond. The RUIP receives and processes the query, returns an answer, then initiates the close of the connection. The local host receives the answer and the close signal, then proceeds closing its end of the connection.</p> </blockquote> <p>The <code>finger</code> command can also provide some custom information, such as full name, email address, and some custom text. Presumably the custom text was used to send the state of the Coke Machine and the coldness of the Cokes inside.</p>

|protocols|

What connectivity protocol did the Carnegie Mellon University's Coke Machine use?

601

<p>I've been reading over the web about the history of the Internet of Things, and one of the most interesting things I have run across is the Carnegie Mellon University's Coke machine. According to various articles I have read, including <a href="http://ewahome.com/internet-of-things-iot/history-of-internet-of-things/" rel="nofollow noreferrer">this one from ewahome.com</a>, it was a Coke machine that was designed to be able to tell people whether cold Coke was available in the University's Coke Machine.</p> <p>I am curious, however, as to what connection protocol would have been used back then for this machine. Were they sending the signals through telephone cables, or what? How did they go about sending the signal up to the various people who wanted information about the Coke?</p>

2017-01-05T16:57:43.183

<blockquote> <p>Is it true that Google will be pushing updates to IoT devices using Android Things without the device developers verifying that it works?</p> </blockquote> <p>Yes, for Android Things devices Google plans to push upgrades continuously without any device developers verifying it.</p> <blockquote> <p>Is this likely to cause breakage?</p> </blockquote> <p>It supposedly is being achieved by ensuring that the device-developer apps and the BSP vendor libraries interact with Android Things OS software components via an API contract only. If and when, the BSP vendor libraries require an update these are upgraded pushed as part of the OS upgrade package.</p> <p>It seems, Google is testing each upgrade in its labs for the first set of devices. This is more close to the Chrome OS model of upgrade and maintenance.</p>

|over-the-air-updates|android-things|

Are Android Things updates going to be delivered automatically?

635

<p>I recently found out about <a href="https://developer.android.com/things/index.html" rel="noreferrer">Android Things</a>, Google's platform for developing an IoT device on top of the Android system.</p> <p>An <a href="https://www.infoq.com/news/2016/12/android-things" rel="noreferrer">InfoQ article</a> suggests that the updates Google provide to Android Things will automatically be pushed to devices:</p> <blockquote> <p>Certified hardware will come with system images provided by Google, including future updates that are automatically delivered without developer’s intervention.</p> </blockquote> <p>However, past experience with Android phones suggests that this is likely to lead to breakage unless the developer reviews the update and approves it before sending it out to consumers. </p> <p>Is it true that Google will be pushing updates to IoT devices using Android Things without the device developers verifying that it works? Is this likely to cause breakage?</p>

2017-01-05T17:05:28.790

<p>One way to debug this would be to run mosquitto manually with the same options as your init system is using, then look at the output. For example:</p> <pre><code>mosquitto -v -c &lt;path to config file&gt; </code></pre> <p>Adding <code>-v</code> will ensure that you have verbose logging, regardless of the config file settings.</p>

|mqtt|raspberry-pi|mosquitto|

Mosquitto on Raspberry Pi refuses connection after changing log settings

636

<p>In my ongoing endeavors to get my Raspberry Pi to command my stuff I set up a Mosquitto MQTT broker. In the base settings everything went reasonably fine.</p> <p>I could post test messages with the publish command and receive them with the subscribe command. Then I decided to up the log level and modified the mosquitto.conf file as follows. The version with essentially the whole log section commented out works. The other doesn't.</p> <p><em>I narrowed it down to the line with the log file.</em> </p> <pre class="lang-bash prettyprint-override"><code>$ diff mosquitto.conf mosquitto.conf.old 408,410c408,410 &lt; #log_dest file /var/log/mosquitto/mosquitto.log --- &gt; log_dest file /var/log/mosquitto/mosquitto.log </code></pre> <p>The file exists and is owned by <code>mosquitto:mosquitto</code>, the user which runs the service.</p> <p>The very helpful message I do get when trying with the logging is the following:</p> <pre class="lang-bash prettyprint-override"><code>mosquitto_pub -h localhost -t thisisme -m 5 Error: Connection refused </code></pre> <p>By now, I'm sure that the service dies a silent death.</p> <pre class="lang-bash prettyprint-override"><code>$ sudo service mosquitto status ● mosquitto.service - LSB: mosquitto MQTT v3.1 message broker Loaded: loaded (/etc/init.d/mosquitto) Active: active (exited) since Fri 2017-01-06 11:16:38 CET; 4min 24s ago Process: 2222 ExecStop=/etc/init.d/mosquitto stop (code=exited, status=0/SUCCESS) Process: 2230 ExecStart=/etc/init.d/mosquitto start (code=exited, status=0/SUCCESS) Jan 06 11:16:38 T-Pi mosquitto[2230]: Starting network daemon:: mosquitto. Jan 06 11:16:38 T-Pi systemd[1]: Started LSB: mosquitto MQTT v3.1 message broker. </code></pre> <p>I'm running <em>Raspbian GNU/Linux 8 (jessie)</em> with the following mosquitto packages:</p> <pre class="lang-bash prettyprint-override"><code>libmosquitto1/stable,now 1.3.4-2 armhf [installed,automatic] mosquitto/stable,now 1.3.4-2 armhf [installed] mosquitto-clients/stable,now 1.3.4-2 armhf [installed] python-mosquitto/stable,now 1.3.4-2 all [installed] </code></pre> <p>Further comment requested information:</p> <pre class="lang-bash prettyprint-override"><code>ls -ld /var /var/log /var/log/mosquitto /var/log/mosquitto/mosquitto.log drwxr-xr-x 11 root root 4096 Sep 23 06:02 /var drwxr-xr-x 8 root root 4096 Jan 6 21:07 /var/log drwxr-xr-x 2 mosquitto mosquitto 4096 Jan 5 14:36 /var/log/mosquitto -rw-r--r-- 1 mosquitto mosquitto 14233 Jan 6 21:07 /var/log/mosquitto/mosquitto.log </code></pre> <p>The only log file in /var/log that gets modified is the auth.log from my sudo.</p> <p><strong>What did I break?</strong></p>

2017-01-05T18:51:56.360

<p>Nope.</p> <p>There are currently just two Bluetooth profiles supported.</p> <blockquote> <p><strong>Advanced Audio Distribution Profile (A2DP)</strong><br> This profile allows you to stream audio from your mobile device (such as a phone or tablet) to Echo.</p> <p><strong>Audio / Video Remote Control Profile (AVRCP)</strong><br> This profile allows you to use hands-free voice control when a mobile device is connected to your Echo.</p> </blockquote> <p>(<a href="https://www.amazon.com/gp/help/customer/display.html/ref=hp_left_v4_sib?ie=UTF8&amp;nodeId=201727450" rel="noreferrer">Amazon Support Page</a>)</p>

|amazon-echo|microphones|

Is it possible to use Amazon Echo as a normal bluetooth microphone for a PC?

639

<p>Amazon Echo contains multiple good microphones. Is it possible to link them to my PC so that I can use the microphone with software like Skype?</p>

2017-01-06T14:06:02.293

<p>I am glad that you got other answers, because NFC is probably the wrong technology for this. </p> <p>Your phone <strong><em>reads</em></strong> NFC tags and acts upon them; no request <strong><em>to</em></strong> the ‘phone, and no to and fro communication. </p> <p>So, at best, you could tag the device – with a URL. When the phone taps the device, it is redirected to a web page which allows the user to visually configure and then instructs the device non-visually on the new configuration. </p> <p>It’s not difficult, but I would recommend one of the other answers. I am posting this only to offer another option to you and any future searchers of this question. </p> <blockquote> <p>Obviously some users will not have NFC-compatible phones, so there would also have to be a secondary method.</p> </blockquote> <p>Indeed :-)</p>

|communication|wifi|nfc|

How can I easily configure Wi-Fi on a smart device without a screen?

651

<p>I'm making an IoT device that will serve a web app over WiFi which can be accessed to control it.</p> <p>I would like to make it easy to set up. For example, the easiest way I can imagine is as follows; all it would need is a phone or similar with NFC capabilities. (Only hypothetically, because this assumes NFC etc can do it!)</p> <ol> <li>User powers up IoT device</li> <li>User holds phone against IoT device's NFC pad</li> <li>IoT device asks phone for WiFi credentials</li> <li>IoT device uses credentials to connect to WiFi</li> <li>IoT device directs phone's browser to its URL</li> </ol> <p>But right away I can see possible flaws: </p> <ul> <li>Phone is unlikely to want to give credentials away; security risk.</li> <li>Phone is unlikely to want to navigate to the given URL; security risk.</li> <li>NFC probably doesn't have defined standards for these kinds of operations; even if security issues are mitigated (e.g. by asking user permission), I can't believe I'd be lucky enough for this to be implemented. So an app would have to be downloaded for the phone to do all this. Which means an app would need to be written for Apple, another for Android etc, plus in the case of Apple it would have to be approved, and either way the user would have to search for it, install it and learn how to use it - all defeating the purpose of having a web interface. </li> </ul> <p>Obviously some users will not have NFC-compatible phones, so there would also have to be a secondary method. </p> <p>The only awareness of a solution I have comes from how my WiFi IP security camera works. It requires first connecting it via Ethernet cable to a router with on a 192.168.1.X subnet with a given IP reserved (e.g. my camera required 192.168.1.100 to be reserved or free). Then from there, the user navigates to <a href="http://192.168.1.100/" rel="noreferrer">http://192.168.1.100/</a>, logs in with the camera's supplied username and password, then from there, configures the camera with the WiFi access point name and password. </p> <p>But that method had one serious disadvantage: it required that the router operates on the subnet 192.168.1.X. Mine operated on 192.168.0.X. Thankfully I was able to reconfigure it. But my new router doesn't have that ability!! I would have been stuck. Additionally, the above method is quite a pain; quite a few steps. </p> <p>What other solutions have been implemented to solve the problem of setting up an IoT device's WiFi connection, and then informing the user of its IP address so he/she can access its web interface?</p>

2017-01-06T21:01:27.100

<p>If your 5W charger can handle the demands, it will use three watts more than the spec of 2W for the cam you linked to. Every two weeks, those three extra watts will use one kilowatt-hour, which I'll guess costs you fifteen cents, or about four (US) dollars annually. A bit of Google-fu found the D-Link DCS-932L delivered for US$ 37. Crunch the numbers, and you are looking at more than nine years before you break even. One consideration you didn't mention was how the phone (cam) will be mounted and aimed. A nicely framed and usable camera angle can be tricky to get without the right equipment. If you're interested in a solution for almost no money, ask, and I'll describe how.</p>

|power-consumption|digital-cameras|microprocessors|

Will reusing a mobile phone as a smart webcam be cheaper than buying a dedicated webcam?

664

<p>With <a href="https://getperch.com/" rel="nofollow noreferrer">Perch</a>, it seems that you can use an old Android smartphone with a camera as a webcam, which seems like a great idea to reuse old devices that you no longer want.</p> <p>However, in normal usage, phones tend to use a <em>lot</em> of energy in my experience (some phones barely last a day on battery in normal usage!), and the camera seems to use even more than usual, so I'm concerned that there may be a lot of power consumption. </p> <p>If I reused a <a href="https://en.wikipedia.org/wiki/Samsung_Galaxy_S_III" rel="nofollow noreferrer">Samsung Galaxy S3</a> with Perch, is it likely to cost more than just buying a webcam and connecting it to my network, or is the difference negligible?</p> <hr> <p>In regards to what I'm comparing, I'm interested in whether (cost of webcam + electricity) would be cheaper than (cost of electricity for phone). If the webcam only pays for itself after 5 or 10 years, I'm not too concerned and won't bother buying it, but if I'm going to see savings after 6 months it might be more valuable.</p> <p>As far as I can tell, Perch just runs the camera 24/7 and communicates via Wi-Fi, but I've turned Bluetooth and mobile data off, along with GPS, since I don't need them.</p> <p>As requested by Mawg, an example of the sort of thing the <a href="https://www.amazon.co.uk/D-Link-DCS-932L-Wireless-Night-Camera/dp/B004P8K24W/ref=sr_1_2?s=computers&amp;ie=UTF8&amp;qid=1483786206&amp;sr=1-2" rel="nofollow noreferrer">D-Link DCS-932L</a>, which says the maximum power consumption is 2W on <a href="http://monitoring.indihome.co.id/views/DCS-932L.pdf" rel="nofollow noreferrer">the datasheet</a>. There isn't any information on the <em>typical</em> power consumption, however, so an answer with some explanation on what might typically be expected could be helpful.</p> <p>I'm not particularly interested in any additional features such as low-light vision, although it would be a bonus. Motion detection <strong>would</strong> be useful though, since Perch does seem to support this by default and it would be advantageous. Notifications of motion would be good as well.</p> <p>The camera will be situated inside, so I wouldn't expect any temperature extremes or dampness (otherwise I have a much bigger problem!).</p> <p>When charging, I would be using a standard 5W USB charger for the phone, which would be connected all the time.</p>

2017-01-07T18:37:48.760

<p>Alright, I guess I can't comment but I can write a separate answer.</p> <p>I looked a bit into the answer by Bence and summarized some more details below.</p> <p>Current links since his are out of date now:</p> <p><a href="https://help.ouraring.com/sleep/validity-of-the-oura-ring-in-determining-sleep-quantity-and-quality" rel="nofollow noreferrer">https://help.ouraring.com/sleep/validity-of-the-oura-ring-in-determining-sleep-quantity-and-quality</a></p> <p><a href="https://ouraring.com/wp-content/uploads/2017/08/Validity-of-the-OURA-Ring-in-determining-Sleep-Quantity-and-Quality-2016.pdf" rel="nofollow noreferrer">https://ouraring.com/wp-content/uploads/2017/08/Validity-of-the-OURA-Ring-in-determining-Sleep-Quantity-and-Quality-2016.pdf</a></p> <blockquote> <p>Epoch by epoch comparison of the sleep stages determined by the ŌURA ring and manually scored based on Polysomnography. Sleep stages were classified into Wake, REM, Light and Deep by both methods. The ŌURA ring was worn on the nondominant hand. The ŌURA ring displays 65.3% agreement, Cohen’s kappa 0.449.</p> </blockquote> <p>The results are improved if you combine light and deep into a non-REM group and results are worse if you wear it on your dominant hand.</p> <p>Some caveats to consider:</p> <ol> <li>Low sample size (n=14)</li> <li>Funded directly by Ouraring (if you think this could bias the study)</li> </ol> <blockquote> <p>Fourteen subjects volunteered to participate in this study. Eight full polysomnograph recordings (four female and four male) and six EOG only recordings (two female and four male) were made. The recording and subsequent analysis was carried out by the sleep laboratory of the Finnish Occupational Health Institute, Helsinki, Finland1), an independent research institute. The research was funded by Ouraring.</p> </blockquote>

|sensors|heart-rate-monitors|oura-ring|

Does the Ōura ring measure heart rate well enough to assess HRV?

678

<p>The wrist-worn devices generally don't measure the heart rate precisely enough to measure heart rate variability (HRV). Does the <a href="https://ouraring.com/why-ring/" rel="noreferrer">Ōura ring</a> measure heart rate precisely enough to get quality HRV data?</p>

2017-01-07T20:01:52.837

<p>I have a D-Link 5020-L IP Camera.</p> <p>Even without D-Link's soft, the messages are transmitted via plain HTTP and a basic autorization header. Which means that if somebody sniffs my home network they can easily get my login/password. And yes, if my router has opened ports my login/password is base64 encoded in the basic header so very easy to read.</p> <p>As for the document I see two parts for what I have read at the beginning:</p> <ul> <li>the first part is "insecure cameras". Well yes, people still don't change the default password of their device. Robots simply perform standard queries to see if cameras are secure, then they list them.</li> <li>the second part is "easy to secure" cameras written on the box. D-Link <em>assures</em> it is easy to secure a camera, but in fact no, people must have a strong knowledge of Wifi protocols (WPA,...) and these settings are hidden behind all the menus of the camera web interface.</li> </ul> <p>With my first point, I would say "all the devices" are impacted since the user must enable security. So, to answer your question: how?</p> <ul> <li><strong>Change the default password of the admin account!!!!</strong></li> <li>If possible, rename the network host via the web interface or via your router, in that case if an attacker finds your device on the network, he won't know it is a [insert brand] camera.</li> <li>Don't expose your camera's port with your router, unless it is a public camera and you have set a guest account.</li> <li><em>Proxyfy</em> your camera: make a webserver perform all the queries to your camera so you can have a visual monitor of who made which queries.</li> </ul>

|security|dlink|

Which D-Link IP cameras are affected by the FTC complaint, and what can I do about them?

684

<p>The FTC have <a href="https://www.ftc.gov/system/files/documents/cases/170105_d-link_complaint_and_exhibits.pdf">filed a legal complaint against D-Link</a> alleging that their routers and IP cameras have critical security vulnerabilities and are misleading consumers into believing they are safe.</p> <blockquote> <p>Defendants have failed to take reasonable steps to protect their routers and IP cameras from widely known and reasonably foreseeable risks of unauthorized access, including by failing to protect against flaws which the Open Web Application Security Project has ranked among the most critical and widespread web application vulnerabilities since at least 2007. </p> </blockquote> <p>I did a bit more research and found the <a href="http://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10069">response from D-Link</a>, saying:</p> <blockquote> <h2>What D-Link Systems products are impacted?</h2> <p>The FTC has made vague and unsubstantiated allegations relating to routers and IP cameras. Notably, the complaint does not allege any breach of any product sold by D-Link Systems in the US.</p> <h2>Is there any security concern for current products?</h2> <p>The FTC does not allege any breach of any product sold by D-Link Systems.</p> </blockquote> <p>It's clear that D-Link don't want to admit that their devices are insecure, from that response. The list of the security vulnerabilities is already provided by the FTC, which is helpful, but they don't actually provide a list of <em>which</em> products specifically are vulnerable.</p> <p>Which products are affected by the complaint, and what actions (if any) can I take to protect my devices and home network?</p>

2017-01-08T06:41:00.943

<p>Generally you'd need some component to trigger and power the sensor and read the response. That sensor has a custom response and trigger which makes me doubt there is a standard ZigBee module out there which converts a command to that 10 µs trigger and reports back the response in verbatim. Thus, you'll need some sort of microcontroller with your ZigBee module to perform that task.</p> <p>I'd probably get that microcontroller, the ZigBee module and a circuit prevent short circuiting on a board outside the well for humidity reasons and lead a four wire cable inside to the sensor. Since the sensor has only four meters of range it has to be very close to the potential high water maximum mark. Putting a small cable inside the well gets the other electronics out of range and puts the ZigBee module in a better position to relay the information to the Raspberry Pi.</p> <p>Of course, you can also put the MCU, the ZigBee module and the sensor in a water-proof casing inside the well. Which might give the ZigBee module problems though. However that depends a lot on your building.</p>

|raspberry-pi|sensors|zigbee|

Connecting a sensor to ZigBee

686

<p>I am planning to measure water level in a well, which is about 10 m deep with maximum water level up to 5 m. My plan is to use ultrasonic sensor <a href="http://www.micropik.com/PDF/HCSR04.pdf" rel="noreferrer">HC SR04</a> to measure depth, transmit it via ZigBee to a Raspberry Pi inside my home.</p> <p>My question is how best to connect HC SR04 to a ZigBee device? Since this sensor will be located inside a well, using minimum parts with lowest power usage would be ideal.</p>

2017-01-08T08:17:53.077

<blockquote> <p>I would like to monitor clients connecting and disconnecting from a separate process that would be subscribing to a system topic where birth and will messages are posted. </p> </blockquote> <p><a href="http://emqtt.io/docs/v2/guide.html#sys-topics">emqtt's User Guide</a> shows a system topic that offers some Broker Statistics, i.e. <code>$SYS/brokers/${node}/stats/clients/count</code> provides the count of current connected clients. Note that this will not list any specifics about the connected clients - so I take it that is not what is needed here. </p> <p>Last will (LWT, Last Will and Testament) messages are otoh not a system topic but a regular topic as set up by the client during connect. If you want to monitor that topic simply subscribe to it. Note however that LWT messages are discarded if a client disconnects gracefully by sending a DISCONNECT message (see <a href="http://www.hivemq.com/blog/mqtt-essentials-part-9-last-will-and-testament">hiveMQ blog</a>, great read btw).</p> <p><a href="http://emqtt.io/docs/v2/commands.html#clients">emqtt's User Guide</a> presents a better way to monitor connecting and disconnecting clients:</p> <blockquote> <p>The <code>./bin/emqttd_ctl</code> command line could be used to query and administrate the EMQ broker (not working on Windows). </p> </blockquote> <p>I think that monitoring <code>clients list</code> - list all MQTT clients - and <code>clients show &lt;ClientId&gt;</code>- show a MQTT Client - are most helpful here. The planned separate process to monitor clients therefore does not need to subscribe to the broker but simply utilize <code>./bin/emqttd_ctl</code> instead. </p> <blockquote> <pre><code> $ ./bin/emqttd_ctl clients list Client(mosqsub/43832-airlee.lo, clean_sess=true, username=test, peername=127.0.0.1:64896, connected_at=1452929113) Client(mosqsub/44011-airlee.lo, clean_sess=true, username=test, peername=127.0.0.1:64961, connected_at=1452929275) </code></pre> </blockquote>

|mqtt|emq|

Subscribing to MQTT birth and will topics? (emqttd)

688

<p>I am running emqttd (<a href="http://emqtt.io/" rel="noreferrer">emqtt.io</a>). I would like to monitor clients connecting and disconnecting from a separate process that would be subscribing to a system topic where birth and will messages are posted. What is the right way to do that?</p>

2017-01-08T13:43:13.900

<p>There's a built in feature in Alexa to prevent exactly this. Go to your app, click settings, alexa account, and then recognized voices.</p> <p>Select &quot;your Voice&quot; and follow the prompts.</p> <p>Hey presto. As you need more people to be able to order things, add their voices as well.</p> <p>Here's what a quick Google search turned up: <a href="https://au.pcmag.com/gallery/59792/how-to-train-amazons-alexa-to-recognize-your-voice" rel="nofollow noreferrer">How to Train Amazon's Alexa to Recognize Your Voice</a></p>

|security|alexa|amazon-echo|

How can I stop Alexa from ordering things if it hears a voice on TV?

695

<p><a href="http://www.theregister.co.uk/2017/01/07/tv_anchor_says_alexa_buy_me_a_dollhouse_and_she_does/?mt=1483795705927" rel="noreferrer">According to The Register</a>, lots of Amazon Echo devices were accidentally triggered by a presenter saying <em>'Alexa ordered me a dollhouse'</em>.</p> <blockquote> <p>Telly station CW-6 said the blunder happened during a Thursday morning news package about a Texan six-year-old who racked up big charges while talking to an Echo gadget in her home. According to her parents' Amazon account, their daughter said: &quot;Can you play dollhouse with me and get me a dollhouse?&quot; Next thing they knew, a $160 KidKraft Sparkle Mansion dollhouse and four pounds of sugar cookies arrived on their doorstep.</p> <p>During that story's segment, a CW-6 news presenter remarked: &quot;I love the little girl, saying 'Alexa ordered me a dollhouse'.&quot;</p> <p>That, apparently, was enough to set off Alexa-powered Echo boxes around San Diego on their own shopping sprees. The California station admitted plenty of viewers complained that the TV broadcast caused their voice-controlled personal assistants to try to place orders for dollhouses on Amazon.</p> </blockquote> <p>Voice purchasing seems to be <a href="https://www.amazon.com/gp/help/customer/display.html?nodeId=201807210" rel="noreferrer">enabled by default</a> on the Echo, if you have 1-Click Purchasing set up.</p> <p>How can I stop Alexa from ordering things if an advertisement or TV show says the words <em>&quot;Alexa, order ____&quot;</em>?</p> <p><strong>Will I need to disable voice purchasing altogether, or is there another way of making Alexa only respond to my orders?</strong></p>

2017-01-08T16:54:53.897

<p><strong>Without Cortana</strong></p> <ol> <li><p>By using the Xbox button on your controller if your controller is paired to your Xbox One.</p></li> <li><p>By using the official Windows 10 Microsoft Xbox app. To make this work, you have to connect your Xbox One to the Windows 10 app by following <a href="https://i.stack.imgur.com/Mi22q.png" rel="nofollow noreferrer">these steps</a>. If streaming works, your Xbox One is connected to your Windows 10 Xbox app. Now shutdown your Xbox One. You should still see your Xbox listed in the Windows 10 Xbox app. It now should also offer you an option to turn on your Xbox One see screenshot below), and there you have it! :)</p></li> </ol> <p>Notice: I only tested this on my Xbox One connected by LAN, Xbox One configured in high energy mode and with the Windows 10 Xbox app version 38.38.14002.00000. Comments if this works on WiFi and on low energy settings are welcome.</p> <p>A screenshot (in dutch) of what this looks like:</p> <p><a href="https://i.stack.imgur.com/Mi22q.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Mi22q.png" alt="enter image description here"></a></p> <p><strong>With Cortana</strong></p> <p>I don't think Cortana supports waking your xbox by using your voice nativly so you need a 3th party script or app. The script or app should use the wake-on-lan protocol and target your xbox one MAC adres to wake it. <a href="https://www.youtube.com/watch?v=y6xTyuLixKg" rel="nofollow noreferrer">This guy</a> has a video about cortana waking his pc, it should also work with your xbox one.</p> <p>Another option might want to look into is using IFTT with the Cortana integration and some other wake-on-lan integration. <a href="https://ifttt.com/applets/480537p-turn-on-xbox-with-google-assistant" rel="nofollow noreferrer">This</a> is an example to wake your xbox one by using Google Assistant. You might create your own working applet without any scripting at all.</p>

|microsoft-windows|wake-on-lan|microsoft-xbox|cortana|

How to turn on Xbox One from Windows 10 PC using Cortana?

703

<p><a href="https://www.microsoft.com/en-us/windows/cortana" rel="nofollow noreferrer">Cortana</a> is Microsoft's intelligent personal assistant for Windows Phone 8.1, Microsoft Band, and Windows 10.</p> <p>I am interested in how can someone turn on their Xbox One by using Cortana voice command. Unfortunately when I was searching in the topic I only found articles about how to turn on Cortana on the Xbox itself. In my case Cortana should listen on my PC running Windows 10.</p> <p>If possible I want to avoid <a href="https://stackoverflow.com/questions/30431688/how-to-connect-cortana-commands-to-custom-scripts">serious scripting</a> and such for first and I hope that there is a more sophisticated solution, if only because all of these are Microsoft products.</p>

2017-01-09T17:47:55.470

<p>Not directly.</p> <p>You could use an authentication plugin such as <a href="https://github.com/jpmens/mosquitto-auth-plug" rel="noreferrer">mosquitto-auth-plug</a> to dynamically add users to a banned list and then force a disconnection by connecting with a duplicate client id.</p>

|mqtt|mosquitto|

Can a Mosquitto MQTT client forcibly disconnect another?

726

<p>I've been wondering how an MQTT client could instruct the broker to disconnect a client by some means, in case I need to force-disconnect a client from my MQTT server (for example, if it's misbehaving somehow and not responding correctly).</p> <p>A <a href="https://iot.stackexchange.com/questions/504/what-will-be-the-result-of-the-following-connection-scenario-in-an-mqtt-network">previous question</a> highlighted the possibility of just connecting with the same client ID as the client you want to kill, but this seems unreliable at best and I'm wondering if there's a more reliable option that will meet my needs:</p> <ul> <li>allows an authorised client to disconnect any other client from the network by client ID</li> <li>ideally, prevents unauthorised clients from disconnecting others (so that only the 'trusted' client can disconnect others)</li> </ul> <p>Is there a feature that meets such requirements?</p>

2017-01-10T17:48:30.683

<blockquote> <p>Is there any technical reason for restricting wake word customization</p> </blockquote> <p>When assistant device is not in use, the application processor (I think ARM in case of Alexa as well as Google Home) is suspended and taken to lowest possible power state. The wake word detection is left to very power efficient DSP which listens to the ambient noise/voices and runs a algorithm to decide if there is a match to the wake word. If it finds a match with good amount of confidence DSP wakes up the ARM core to get going with rest of the processing.</p> <p>Now since the goal is to be power efficient the DSP in question runs the algorithm as well as stores the template pattern on the on-chip memory rather than the main on-board RAM. This allows system to even take the DDR RAM to lowest power state.</p> <p>Since the DSP has a number key things to do and very little on-chip memory the Assistant wake words are limited to a few choicest ones that can be matched by the algorithm with high degree of confidence.</p>

|smart-home|smart-assistants|

Why do most smart assistants offer little, if any, customisation of the wake word?

736

<p>The majority of <em>smart assistant</em> brands, such as the Amazon Echo and Google Home, offer very little in the way of customisation for the wake word (the phrase you use to wake up the device so it listens to you).</p> <p>For example, <a href="https://iot.stackexchange.com/questions/524/how-to-change-the-amazon-echo-wake-word">Alexa only offers three choices</a> and Google Home only supports <em>'OK Google'</em>. A lot of users seem to be interested in the idea of custom wake words, yet none of the major brands have added support.</p> <p><strong>Is there any technical reason for restricting wake word customisation, or is it simply a branding choice?</strong> </p> <p>I've read about <a href="https://blog.google/products/assistant/personal-google-just-you/" rel="nofollow noreferrer">Google's motivation for using <em>'OK Google'</em></a>, which suggests the branding idea might be true, but it also seems that wake word recognition <a href="https://www.reddit.com/r/amazonecho/comments/5n23tk/does_your_echo_also_respond_to_the_name_calypso/" rel="nofollow noreferrer">isn't very accurate</a>, perhaps indicating a technical reason. Would anyone be able to clarify which factor is the main reason?</p>

2017-01-12T12:41:17.787

<p>One reason would be for a large house. We have 3 Alex devices, in the Master bedroom, Living Room and Lounge.</p> <ul> <li>You can now sort of link a device to a room, but its still wishy washy.</li> <li>Sometimes we listen to news or music on the device itself, with a few of us around, its convenient to listen to different things in different rooms.</li> <li>We also have speakers in the ceilings and Alexa is linked to that, so we can play on the ceiling speakers. It would be rather inconvenient to walk from the Lounge all the way to the Master just to change what you are listening to on the Lounge speakers. Conversely, the Lounge doubles as a media room, so you wouldnt want to interrupt a movie for others, just to change what is playing in the Living Room.</li> <li>I would also rather not shout or scream!!!</li> </ul>

|alexa|amazon-echo|

Why would I need multiple Alexa devices in one home?

758

<p>As a result of this <a href="https://iot.stackexchange.com/questions/695/how-can-i-stop-alexa-from-ordering-things-if-it-hears-a-voice-on-tv">question</a> I have read some articles about Alexa and its wake-words. One of the <a href="http://www.howtogeek.com/249342/how-to-change-the-amazon-echos-wake-word/" rel="nofollow noreferrer">articles</a> mentions the following:</p> <blockquote> <p>Finally, for people with multiple Echo units, there’s an argument to be made for multiple wake words. The microphone array on the Echo and Echo Dot units is very sensitive. If you have an Echo in your living room and a Dot upstairs in your bedroom, there’s a good chance that issuing a command to Alexa while standing in the foyer will trigger both units. In such instances, it’s really handy to have one wake word for the downstairs unit and one wake word for the upstairs unit.</p> </blockquote> <p>Now it says that:</p> <blockquote> <p>The microphone array on the Echo and Echo Dot units is very sensitive. If you have an Echo in your living room and a Dot upstairs in your bedroom, there’s a good chance that issuing a command to Alexa while standing in the foyer will trigger both units.</p> </blockquote> <p>So then why would I need more of them when one can cover an average home? What are the possible use-cases that reasons having multiple Alexas at home?</p> <p>Also to extend coverage it could be enough to use a simple wireless microphone unit connected to Alexa.</p>

2017-01-12T20:32:47.543

<p>Yes. IoT devices (e.g. wifi thermostat) with no open/listening ports, such as telnet or http, usually dial into a central server, and stay connected to that server 24/7. When you are abroad, the thermostat app on your smartphone contacts the same CENTRALIZED server when you want to change the temperature, and that server relays the command back to the thermostat at your house. If hackers compromise that server, they have control of the thermostats. It was in Mr. Robot season 1. You can use certain blockchains, such as Ethereum, to interact with an IoT device, instead of a using a centralized server. An example is the SlockIt ethereum door lock</p>

|security|networking|blockchains|

Could a blockchain really prevent malware in the Internet of Things?

764

<p><a href="https://www.rtinsights.com/blockchain-technology-and-iot-security/" rel="noreferrer">This article</a> claims that using a blockchain-based security system for an IoT network would prevent some types of attacks:</p> <blockquote> <p>Blockchain technology may help offer an answer. Gada observes that blockchain offers inherent security not present in current, traditional networks. “Blockchain technology is seen as a way to add security and privacy to sensors and devices,” he states. “In traditional IT architectures, tampering can occur if a hacker is able to get through firewalls and other defenses built up by an organization. Once inside, tampering is often not recorded or noticed, and can occur unimpeded. This is simply not possible when using blockchain.”</p> <p>Blockchain, Gada explains, is “a suitable solution in at least three aspects of IoT, including big data management, security and transparency, as well as facilitation of micro-transactions based on the exchange of services between interconnected smart devices.”</p> </blockquote> <p>This seems like a bold, yet rather vague claim. <strong>How, exactly, would a blockchain system provide such protection to a network of connected devices?</strong> Are the benefits mainly due to the improved transparency of the public blockchain, or are there other benefits too?</p>

2017-01-13T19:58:33.807

<p>Messages are persisted to disk not just held in memory.</p> <p>Look at the <code>autosave_interval</code> and <code>autosave_on_change</code> options for when the messages get written to disk.</p> <p>_{<a href="https://mosquitto.org/man/mosquitto-conf-5.html">Source</a>}</p>

|mqtt|mosquitto|

What happens if Mosquitto runs out of memory to store QoS 1/2 messages?

784

<p>In MQTT, messages with QoS 1 or 2 <a href="http://www.hivemq.com/blog/mqtt-essentials-part-6-mqtt-quality-of-service-levels"><em>must</em> be delivered at least once</a> (QoS 2 messages must be delivered <em>exactly</em> once). If the client is not connected, the broker must store the message until the client is ready to receive it.</p> <p>The <a href="http://www.hivemq.com/blog/mqtt-essentials-part-7-persistent-session-queuing-messages">HiveMQ blog</a> has an interesting point:</p> <blockquote> <p><strong>But what happens if a client does not come online for a long time?</strong> The constraint for storing messages is often the memory limit of the operating system. There is no standard way on what to do in this scenario. It totally depends on the use case. In HiveMQ we will provide a possibility to manipulate queued message and purge them.</p> </blockquote> <p>Since this seems to be dependent on the broker, <strong>how does Mosquitto handle this situation?</strong> Does it just crash after running out of memory or are old messages finally purged?</p>

2017-01-13T21:01:56.710

<blockquote> <p>So how does EMQ persist QoS 1/2 messages until delivery, i.e. a reboot of the broker or with respect to memory limits?</p> </blockquote> <p>The answer seems to be: <strong>it doesn't</strong>. <a href="https://github.com/emqtt/emqttd/issues/827" rel="noreferrer">This issue</a> on their bug tracker says:</p> <blockquote> <p><em>I am facing the issue to store persistent client sessions after broker restart. Does this feature currently not present in the broker or I missing some configuration?</em></p> <p>The broker will not persist sessions.</p> </blockquote> <p>Also, after digging through a couple more issues, I found <a href="https://github.com/emqtt/emqttd/issues/726" rel="noreferrer">this report</a>:</p> <blockquote> <p>Initially I have set the max clients to 1000K in emqttd.config. Our machine has 8 GB memory with 4 core, I am able to connect 120K concurrent connection easily but when it exceeds 8 GB memory emqttd terminates itself. What I thought is set a max client per machine would be far better.</p> </blockquote> <p>Essentially, as of v2.0.5:</p> <ul> <li>Messages do not seem to be persisted to a file.</li> <li>Once the broker runs out of memory, it will simply crash.</li> </ul> <p>Not exactly ideal, but that seems to be the current behaviour, so if persisting messages is critical to your use-case, use a different broker.</p>

|mqtt|emq|

How does EMQ persist QoS 1/2 messages?

786

<p>The <a href="http://emqtt.io/docs/v2/index.html" rel="noreferrer">EMQ (Erlang MQTT Broker)</a> is a "distributed, massively scalable, highly extensible MQTT message broker" with a reported "1.3 million concurrent MQTT connections" - so it potentially allows a large number of clients to publish and subscribe to it. It seems likely that some clients may be disconnected at any given time.</p> <p>As this question <a href="https://iot.stackexchange.com/q/784/54">What happens if Mosquitto runs out of memory to store QoS 1/2 messages?</a> asks about Mosquitto:</p> <blockquote> <p>In MQTT, messages with QoS 1 or 2 <a href="http://www.hivemq.com/blog/mqtt-essentials-part-6-mqtt-quality-of-service-levels" rel="noreferrer"><em>must</em> be delivered at least once</a> (QoS 2 messages must be delivered <em>exactly</em> once). If the client is not connected, the broker must store the message until the client is ready to receive it.</p> </blockquote> <p>So how does <strong>EMQ</strong> persist QoS 1/2 messages until delivery, i.e. a reboot of the broker or with respect to memory limits?</p>

2017-01-14T10:06:26.940

<p>There are two ways that you can achieve this unless the devices you have in-home are configured to access an external server specifically to provide this function (most are).</p> <p><strong>A VPN</strong> can be used to logically move your android device to inside your home network. It is possible (but unlikely) that your router provides this functionality. In practice, you need a device within your home network to act as a host for the VPN. I use a NAS device (which comes with the DNS features as well), but you could implement this yourself using a single board computer (such as a Raspberry Pi).</p> <p><strong>Router Port Forwarding</strong> This is technically possible, but less likely to work in your case. It would work if the device in your house has a web interface, but doesn't work so easily if you have an app which you need to redirect from an external network. You can configure your router to pass an HTTP access on a special port (public_ip:12380) to port 80 on your entertainment device (192.168.1.xx:80). This would be OK (and easy) if you have a device running Kodi for example, this had a web remote-control.</p> <p>However, based on your asking the question, I'd say this is probably going to be very hard to set up, even using a NAS which supports a VPN isn't simple. It might be worth investigating if a device like Google-home can implement the link you need.</p>

|smart-home|wifi|

Connect to device at home network remotely

787

<p>I am trying to figure out if it is possible in any way for me to remotely connect to a device on my home network, but remotely.</p> <p>Scenario:</p> <p>My entertainment system is connected to the home network, and every now and then when I'm at work (50 km away) I would like to activate it (usually because family doesn't know how to operate it) using the Android App the device maker has which I have installed on my phone.</p> <p>Normally I would connect to Wi-Fi, and done app instantly connects to entertainment unit and starts operating.</p> <p>But in this scenario would like to know how to achieve the same but from 50 km away not on same home WiFi connection.</p> <p>I looked into DDNS but that didn't add up, as well as VPN but nothing adds up.</p> <p>Keen to learn how to make the whole smart home work (all my electronic devices at home are connected to wireless network).</p> <p>Router: Netgear D6400 Devices: AVR-x1100w, (i got couple controllers as well I'm going to be installing for light fixtures and air con). They all have web interface too.</p>

2017-01-14T16:56:11.190

<p>There are two obvious points of entry for an attacker. One is the local network connection, the other is the WAN. Even if you defend against these, you need to ensure that there is nothing valuable which is known to the device since it provides an easy attack point for other devices.</p> <p>A wired connection for the local network is most secure, but only if it is isolated from the rest of your network. If you have to provide a WiFi connection, use a SSID dedicated to this camera, with unique secrets.</p> <p>In order to open access to the isolated, insecure network segment, you need to set up a VPN. Ideally, the VPN will be the only way to connect to this isolated segment. In practice, it will still be vulnerable to local attack.</p> <p>Be sure not to connect the DVR to any other shared resources on your LAN such as networked storage.</p>

|smart-home|security|

What can I do if a smart DVR camera only supports default passwords?

796

<p>An awful lot of devices on the market for home automation have severe security flaws, such as hard-coded passwords (or no passwords at all!). To make it worse, it's hard to find information on the Internet about a device's security before purchasing, so it's easy to buy something only to find out that it's blatantly insecure.</p> <p><a href="http://www.securityperspectives.com/three-reasons-may-need-throw-away-smart-devices/" rel="noreferrer">This article</a> suggests that the only option in this case is to return the device or throw it away:</p> <blockquote> <p>So, if the device has no password, or you can’t change the password it uses, it’s always going to be vulnerable to attack. You’ll need to throw it out and buy a new one that was built with at least the ability to change its password.</p> </blockquote> <p>I suspect it might be possible to reduce the risk by restricting access to my devices to certain remote IPs, although I'm unsure as to whether that would completely solve any future problems.</p> <p>The product I'm interested in particularly is the Raysharp DVR, which <a href="http://www.pcworld.com/article/3034265/hard-coded-password-exposes-up-to-46000-video-surveillance-dvrs-to-hacking.html" rel="noreferrer">allegedly uses hard-coded passwords</a> and offers no way of changing the authentication credentials. <strong>What actions can I take to prevent unauthorised access while still being able to use the camera from outside my home network?</strong></p>

2017-01-15T14:02:48.947

<p><a href="http://public.dhe.ibm.com/software/dw/webservices/ws-mqtt/mqtt-v3r1.html" rel="noreferrer">Version 3.1 of the spec</a> suggested some unreasonably low username/password lengths:</p> <blockquote> <p>It is recommended that user names are kept to 12 characters or fewer, but it is not required.</p> <p>It is recommended that passwords are kept to 12 characters or fewer, but it is not required.</p> </blockquote> <p>I imagine that any sensible broker didn't implement this recommendation.</p>

|security|mqtt|

Why does this whitepaper say MQTT usernames/passwords "do not provide enough entropy"?

804

<p><a href="https://lists.oasis-open.org/archives/amqp/201202/msg00086/StormMQ_WhitePaper_-_A_Comparison_of_AMQP_and_MQTT.pdf" rel="nofollow noreferrer">This whitepaper</a> comparing MQTT and AMQP says that MQTT's username/password restrictions make it far less secure than AMQP:</p> <blockquote> <p>MQTT requires short user names and short passwords that do not provide enough entropy in the modern world.</p> </blockquote> <p><a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718031" rel="nofollow noreferrer">Section 3.1.3.5 of the MQTT specification</a> says that passwords can be up to 65535 bytes of binary data. A <a href="http://www.wolframalpha.com/input/?i=(Sum+from+1+to+65535+of+256%5En)" rel="nofollow noreferrer">quick calculation</a> shows that this produces a ludicrously large number:</p> <p><a href="https://i.stack.imgur.com/EdSca.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/EdSca.gif" alt="Wolfram Alpha Calculation = 1 x 10^157824"></a></p> <p>To put that into scale, if you could try <strong>one hundred trillion</strong> passwords a second, it would take approximately 1 x 10¹⁴ <strong>million years</strong> to exhaust the search space of any password between 1 and 65535 bytes.</p> <p>Therefore, I can only assume that the author is either incorrect, or that they were talking about a restriction that occurred previously but has now been lifted.</p> <p>Why would the author of that whitepaper say MQTT's passwords have insufficient entropy, and is it still the case, or are my calculations correct?</p>

2017-01-16T16:12:12.623

<p>For near-real time tracking of vehicles while out of cellular service range, Spot makes the <a href="https://www.findmespot.com/en/index.php?cid=128" rel="noreferrer">Spot Trace</a>, a vehicle tracker that uses satellite communication. It transmits only when the vehicle has moved or is in motion, and only as often as you configure it for, minimizing data traffic over the satellite link. It operates on alkaline batteries (for concealed placement) or vehicle power.</p> <p>If you just need a product and don't feel the need to build one, this is a pretty inexpensive way to meet your stated needs.</p> <p>If you still want to customize it further and/or build something yourself, <a href="http://www.globalstar.com/en/index.php?cid=1310" rel="noreferrer">Globalstar offers a variety of satellite and satellite+GPS communications modules</a>.</p>

|raspberry-pi|gps|

Robust GPS + Internet - Best option?

812

<p><strong><em>Please consider the following:</em></strong></p> <p>I am looking to build a device that will be placed in a vehicle as it drives through heavy wooded areas, potentially far away from any mobile reception towers.</p> <p>The hope is for this device to be able to get its GPS location in near real time, and upload said information to either, another device, or best case: the internet, but the key point would for this to be as uninterrupted as possible.</p> <p>The device must not require any modification to the vehicle (attaching antenna to the roof etc) other than being powered/charged from a 12V cigarette lighter.</p> <p>Is my best option here to build an app and use a high quality mobile phone, or would it be to build a custom device with some kind of satellite internet, and high quality GPS module.</p> <p>If the custom device I would consider using a Raspberry Pi as the controller for it, can anyone suggest equipment that could be used in this?</p> <p>Many thanks,</p> <p><strong>Edit</strong></p> <p>I would also <em>love</em> to see any examples of similar projects for some brainfood.</p>

2017-01-16T17:38:27.927

<p>One of the answers above says that CoAP uses UDP and hence does not guarantee data delivery. This is not completely true. CoAP has a non-confirmed mode and a confirmed mode of sending messages. In confirmed mode, CoAP will do retries to try to ensure delivery. You can tune the timeout and retry attempt count. The non-confirmed mode does not retry and is the 'fire-and-forget' mode you mention above.</p> <p>In terms of memory footprint, the code itself can take 5-200k depending on what library you use and what options you use. The runtime data use depends on what features you use such as confirmed mode, block transfer, security, named resources, etc. For a tightly constrained trial, see <a href="https://www.mdpi.com/1424-8220/16/3/358" rel="nofollow noreferrer">https://www.mdpi.com/1424-8220/16/3/358</a> where the CoAP part of the code is about 5k !</p>

|mqtt|communication|protocols|coap|

Does CoAP have a lower footprint than MQTT?

813

<p>I recently read a <a href="https://www.quora.com/Which-is-more-lightweight-as-IoT-protocol-MQTT-or-CoAP">Quora question</a> about whether CoAP or MQTT is more lightweight, but the answers don't seem particularly satisfying and all contradict each other: the top answer says MQTT takes fewer resources, and another below that says CoAP is less demanding.</p> <p>From what I've found, it would make sense that <a href="https://en.wikipedia.org/wiki/Constrained_Application_Protocol">CoAP</a> would be less demanding than <a href="https://en.wikipedia.org/wiki/MQTT">MQTT</a>, since CoAP only requires UDP, and its messages are mainly fire-and-forget, unlike MQTT which functions over TCP (and hence would be much more involved).</p> <p><strong>Which protocol requires the least resources to function?</strong></p> <hr> <p>^{By resources, I'm primarily thinking of required processor power, RAM and data to be transmitted. For example, in the Quora question I linked, the top answer points out that a simple <a href="https://en.wikipedia.org/wiki/ESP8266">ESP8266</a> chip could run MQTT, which only has a 80MHz processor and less than 1MB of RAM. I'm curious as to whether CoAP could run on something like this, or an even more constrained environment.}</p> <p>^{The sort of use case I'm envisaging is where the device would mostly be receiving data from another device (e.g. commands to switch on/off), but may need to infrequently (perhaps a few times an hour) send updates with the device's status. I'd like to use as little processing power as possible to reduce device costs, and transmit relatively infrequency to reduce power usage as much as possible.}</p>

2017-01-17T16:23:38.377

<p>Alternatively it might be worth to consider <a href="https://en.wikipedia.org/wiki/WirelessHART" rel="nofollow noreferrer">wireless Hart (Highway Addressable Remote Transducer)</a>. This is a 2.4GHz ( license free frequency band) Smart mesh networking technology that uses 802.15.4 standard. WHart use direct-sequence spread spectrum technology and needs at minimum three main components. Namely wireless devices, gateway and network manager. </p> <p><a href="https://i.stack.imgur.com/gke9e.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/U0aIV.jpg" alt="Wireless hart network"></a></p> <p>_{<em>Click on image for a larger version of the image.</em>} </p> <p>Additionally depending on the network, security manager, adapters, and handheld terminals can be added. </p> <p>Dust network offers a SOC option and some of them have I2C interface. Attach below is a links to some of the datasheet. Unfortunately my knowledge on this technology is pretty limited thus warrant further research. </p> <p><strong>References</strong></p> <ol> <li><a href="http://cds.linear.com/docs/en/datasheet/59012ipmfa.pdf" rel="nofollow noreferrer">LTP5901-IPM/LTP5902-IPM</a></li> <li><a href="http://en.hartcomm.org/hcp/tech/wihart/wireless_how_it_works.html" rel="nofollow noreferrer">WirelessHART - How it works</a></li> </ol>

|networking|communication|bluetooth|

Is Bluetooth 3.0 suitable for a single-master multiple-slave network?

819

<p>I have a data logger board with a <a href="http://simcom.ee/modules/gsm-gprs-gnss/sim808/" rel="noreferrer">SIM808</a> on it. It has Bluetooth 3.0 capability by the SIM808. The board itself implements a battery management system, capable of performing weight, humidity and temperature measurements and also can detect device displacements. All collected data is transferred by GPRS connection to a remote server.</p> <p>The device itself can be installed into beehives, but it would not be cost effective to have a SIM card for hundreds of hives. So this will only act as a <strong>master</strong>, that have data logging capabilities as well beside the GPRS capability.</p> <p>Thus, I am planning to implement <strong>slave</strong> boards without the SIM808 modules. So instead of the SIM808, a simple wireless communication unit is needed to enable local, wireless communication between the hives.</p> <p>The master would query all the slaves for their data, and then it would transfer everything via GPRS.</p> <p>It should look like this, only with a hundred hives:</p> <p><a href="https://i.stack.imgur.com/Q4gFU.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Q4gFU.png" alt="enter image description here"></a></p> <p>Now <strong>the possibilities</strong> for local wireless communication:</p> <ol> <li>Bluetooth, as I said the master device already have Bluetooth 3.0. But I am not entirely sure that Bluetooth is the right way to query a hundred slave for 1 kBs of data.</li> <li>The master device has an I2C bus, so I can connect I2C compatible ZigBee or other RF module which could be added to the slave boards as well.</li> </ol> <p>Collectable data from slaves won't exceed 1 kB/query.</p> <p>So all in all can I stay at Bluetooth or should I add ZigBee for example to my devices or are there any other options?</p> <p>Some more details:</p> <ul> <li>range is max 30 meters</li> <li>also as the devices are battery powered, a solution with low power consumption would be good</li> <li>the master would run a query in every 15 mins</li> </ul> <p><strong>The main goal is to make the master able</strong> to query the slaves efficiently, and this should be done <strong>without modifying the PCB of the master</strong>. The two possibilities are Bluetooth 3.0, which is already available for the master, or other technologies that I can connect to the master board via the I2C bus of the on-board MCU. (I do not insist on using Bluetooth, it was the starting point because I already had a BT 3.0 by the SIM808.)</p> <p><a href="https://i.stack.imgur.com/HPteD.png" rel="noreferrer"><img src="https://i.stack.imgur.com/HPteD.png" alt="enter image description here"></a></p>

2017-01-17T20:29:45.223

<p>I don't have SmartThings, but do have Google, so here is half an answer.</p> <p>Comments above <a href="https://community.smartthings.com/t/backup-settings-and-restore-in-smartapps/16182" rel="nofollow noreferrer">from me</a> and <a href="https://community.smartthings.com/t/backup-settings-devices/48296" rel="nofollow noreferrer">Prashanth</a> to SmartThings forum(*) discussions (here, and here) indicate that backup / restore is not available to the casual user.</p> <p>However, the SmartThings <a href="http://docs.smartthings.com/en/latest/index.html" rel="nofollow noreferrer">developer documentation</a> (which seems quite extensive), give information about overall preferences and settings <a href="https://community.smartthings.com/t/backup-settings-devices/48296" rel="nofollow noreferrer">here</a> and <a href="http://docs.smartthings.com/en/latest/smartapp-developers-guide/preferences-and-settings.html" rel="nofollow noreferrer">here</a>.</p> <p>And <a href="https://community.smartthings.com/t/can-i-set-defaults-for-input-values-in-the-preferences-section-of-a-custom-device-type/18664" rel="nofollow noreferrer">this discussion</a> on the forum appear to show how to programmatically set preferences, which is half of your question answered (and, of course, of little use if you can’t read the preferences to back them up).</p> <p>I would suggest reading the copious documentation and, if necessary, asking on the SmartThiungs forum, to discover how to backup preferences and settings.</p> <hr> <p>(*) which might be the best place to ask, rather than here. Great as we are, here on SO, I would always recommend asking in a dedicated forum first, for any subject, before asking here.</p>

|samsung-smartthings|data-portability|

Can I backup/export settings from SmartThings?

822

<p>I was wondering if SmartThings supports backing up the settings (or perhaps exporting it in a machine-readable format such as JSON or XML), so that if worst comes to worst, I won't lose my settings and configuration.</p> <p>I read <a href="https://community.smartthings.com/t/backup-settings-devices/48296">this thread</a> which suggests that there is no official tool as of May 2016. <strong>Is this still the case? If so, is there any other way to backup or extract the settings from the hub?</strong></p>

2017-01-18T15:35:33.407

<p>When mixing the advert's audio, they simply remove some frequencies. This means that Alexa won't be triggered as it will not register it as a voice command, but viewers can still make out what they are saying in the advert.</p> <p>You'll also probably notice that when the command is spoken in the adverts, it sounds a little thin or garbled. This is why :)</p>

|amazon-echo|

Why doesn't the Amazon Echo respond to advertisements or reports about Alexa?

828

<p>I previously asked about <a href="https://iot.stackexchange.com/questions/695/how-can-i-stop-alexa-from-ordering-things-if-it-hears-a-voice-on-tv">what you can do if Alexa <strong>is</strong> triggered by a television programme</a>, but recently I realised something strange: The Echo <strong>does not</strong> respond to the voices in adverts for the Echo, even if voices say <em>"Alexa, play ..."</em> or <em>"Alexa, set a timer for ..."</em>.</p> <p>I searched on a few other Echo communities, and found a <a href="https://www.reddit.com/r/amazonecho/comments/56gmyf/so_on_the_new_commercial_with_the_uber_pause_and/" rel="noreferrer">Reddit post</a> that suggests that this is common/intended behaviour. There isn't a definitive answer in the thread, though, so I thought I would ask here to see if someone knows a little bit more.</p> <p><strong>How does my Echo know <em>not</em> to answer to a TV advert?</strong> Is it just a co-incidence or is there something that tells Alexa not to react?</p>

2017-01-19T06:19:17.623

<p>Basically what you need to do is merge together the MQTT subscriber code with a ZeroMQ sender in Java, such that when you receive a message from the MQTT queue, it gets transferred to the 0MQ for 0MQ listeners to receive.</p> <p>I haven't used MQTT from Java, but a popular library seems to be <a href="https://stackoverflow.com/questions/22715682/subscribe-and-read-mqtt-message-using-paho">Paho</a>.</p> <p>The 0MQ documentation and example code is excellent, and a Java example can be found <a href="http://zguide.zeromq.org/java:hwclient" rel="nofollow noreferrer">here</a>.</p>

|mqtt|zeromq|

How can we get messages from an MQTT broker and put them into the ZeroMQ queue?

832

<p>I am trying to get messages from an MQTT broker and insert that messages into ZeroMQ. What do I need to do to connect an MQTT broker to <a href="http://zeromq.org/" rel="noreferrer">ZeroMQ</a> in java?</p>

2017-01-19T09:16:19.267

<p>You are correct the, DSP is a separate processor within the CSR8675. It has its on program and data memory.</p> <p>All image are taken from the linked datasheet.</p> <p><a href="https://i.stack.imgur.com/2FmlK.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2FmlK.png" alt="block picture around the mcu&#39;s DSP"></a></p> <p>The DSP (<a href="https://en.wikipedia.org/wiki/Digital_signal_processor" rel="nofollow noreferrer">Digital Signal Processor</a>) is a dedicated processor. It has additional hardware units, parallel instruction execution support that gives you a better platform with better performance to process audio, video and such signals where huge amounts of data has to be processed in short time. Check the link for more details. The audio handling part of your software should be implemented on this processor.</p> <p>The MCU is a more general unit, the datasheet calls it "application processor". It is used for the higher logic of your application. While the DSP handles the audio signals, general thing such as LED driving, capacitive sensing and USB connection can be handled by this MCU. </p> <blockquote> <p>The BlueCore® CSR8670™ BGA consumer audio platform for wired and wireless applications integrates an ultra-low-power DSP and <strong>application processor</strong> with embedded flash memory</p> </blockquote> <hr> <p>As for the firmware and VM. Page 104 gives you a comprehensive figure of the software.</p> <p><a href="https://i.stack.imgur.com/zLfa9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zLfa9.png" alt="model of the mcu&#39;s firmware architecture"></a></p> <p>The firmware means the whole software of the device and consists of different parts.</p> <ul> <li>On-chip software on the MCU by the manufacturer. This can be for example the BT stack, just as you suspected. <blockquote> <p>The internal MCU runs the Bluetooth stack up to the HCI.</p> </blockquote></li> <li>Applications on the MCU (in the VM) by you. The VM is the environment where your application software can be placed within the MCU's program memory. <blockquote> <p>The software layers for the application software run on the internal MCU in a protected user-software execution environment known as a VM</p> </blockquote></li> <li>DSP Application, again by you just on a separate unit. <blockquote> <p>DSP application code runs from the DSP program memory RAM</p> </blockquote></li> </ul>

|microcontrollers|audio-dsp|csr-adk|

What is the difference between MCU, VM, firmware and Kalimba DSP in the CSR8675 chip?

834

<p>This question is about understanding the internal workings of the CSR8675 Bluetooth audio chip </p> <p>These four terms keep popping up while working with the CSR8670/8675 chip </p> <ol> <li>VM (Virtual machine) </li> <li>Firmware </li> <li>MCU (Microcontroller Unit)</li> <li>Kalimba DSP </li> </ol> <p>Could someone please explain in detail what exactly is the difference between them? I have some understanding of the differences between VM and firmware, and I believe that the kalimba DSP can be considered a completely separate processor just packaged inside the same 8675 chip, but where does the MCU fit into all of this? Is the bluetooth stack a part of the MCU as well? </p> <p><a href="https://i.stack.imgur.com/Fi1p7.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/Fi1p7.jpg" alt="block model of the mcu and the interfaces"></a> </p> <p>8670 datasheet can be downloaded <a href="http://www.datasheet-pdf.com/PDF/CSR8670-Datasheet-CSR-785475" rel="noreferrer">here</a></p>

2017-01-19T18:30:40.620

<p>I use Alexa, it does recognizes voices. Also, my Alexas are not placed that close to the door. I also have double glazing. So, you would have to shout really really loud, it will probably need a loud speaker.</p> <p>On the other hand, in modern houses, ingress is hardly an issue, just break any of the glass panes on windows or doors.</p> <p>I have what is called an electric door strike for my front and back doors. They are controlled by a secure keypad, for us to use to come in keylessly. But it is controllable by Alex as well.</p>

|samsung-smartthings|google-home|

How can I securely support unlocking my door through Google Home?

838

<p>There are several brands of <a href="https://www.smartthings.com/works-with-smartthings/locks">door locks supported by SmartThings</a>, all of which could be used to secure someone's front door. After some research, I found it was possible to <a href="https://community.smartthings.com/t/google-home-door-locks/62423">create a virtual switch to control the lock, so that Google Home can control it</a>.</p> <p>However, in that thread, there's an interesting point about controlling locks through a voice assistant:</p> <blockquote> <p>One concern people have raised. If you enable voice control of locks, someone could stand outside your house and tell your voice system to unlock the lock.</p> </blockquote> <p>Surprisingly (or perhaps not!), this has already happened with an <a href="http://www.forbes.com/sites/aarontilley/2016/09/21/apple-homekit-siri-security/#1baaa1ca6e8a">August Smart Lock controlled by Siri</a>:</p> <blockquote> <p>Last Friday morning, as Marcus was pulling out of the driveway, Mike [Marcus' neighbour] walked up with a grin asking if he could borrow some flour. Marcus responded sure and started to get out of the car to let him in. But before Marcus could do anything, his neighbour said, "I'll let myself in," and ran over to the front door. He then shouted, "Hey Siri, unlock the front door." The door unlocked.</p> </blockquote> <p><strong>For the setup of a Google Home controlling a SmartThings lock that I proposed at the start of the question, how can I avoid intruders or unwanted visitors from opening my front door?</strong> Is the only viable option simply <em>disable it altogether</em>, or might it be possible to modify the setup so that it is more secure?</p>

2017-01-19T21:18:26.360

<p>It's been nearly 7 years since I asked this question, and a web search in 2024 still shows no relevant results. I'm going to answer this as &quot;no, there have been no real-world deployments of HomeWSN.&quot;</p>

|smart-home|mqtt|

Any real-world HomeWSN deployments?

840

<p>I searched for "MQTT Rules Engine", and came across the <a href="http://homewsn.com/" rel="noreferrer">HomeWSN</a> project. It looks like it's almost trying to be a home automation system based on MQTT messaging, which could be very useful. Has anyone deployed a real system based on this tool?</p>

2017-01-20T16:48:58.753

<p>I found a slight variation of the above steps to work:</p> <ol> <li>Unplug for 10 seconds</li> <li>Plug back in and immediately tap mute once (the microphone will turn red)</li> </ol> <p>Your unit will then immediately update. Takes about half an hour to complete. </p>

|amazon-echo|

How do I force my Amazon Echo to update to the latest version?

845

<p>Version 4812 of the Echo software <a href="https://www.reddit.com/r/amazonecho/comments/5nrxk7/german_amazon_website_confirms_wakeword_computer/" rel="noreferrer">apparently includes the new 'Computer' wake word</a>, which seems really exciting. However, my device is still running version 4540 and hence doesn't have the wake word yet.</p> <p>The <a href="https://www.amazon.co.uk/gp/help/customer/display.html?nodeId=201602210" rel="noreferrer">Amazon documentation</a> says:</p> <blockquote> <p>Your Alexa device receives software updates automatically over Wi-Fi.</p> <p>To download the latest software update for your Alexa device:</p> <ul> <li>Make sure your device is on and has an active Wi-Fi connection.</li> <li>Avoid saying anything to your device while performing the update.</li> <li>When the update is ready to install, the light ring on your device turns blue and the device installs the latest update. Depending on your Wi-Fi connection, it can take up to 15 minutes to install the software update.</li> </ul> </blockquote> <p>However, it doesn't explain how to actually <strong>initiate</strong> the updating process. <strong>Can I force my Echo to update in any way, or do I just have to wait for it to perform the self-check?</strong></p>

2017-01-20T18:08:38.477

<p>The bulk of your power will likely be expended on RF transmission, not CPU cycles spent in encryption routines. Every additional bit transmitted will cost you more power than the encryption you're proposing. That means if you take a naive approach, like using AES in CBC mode, you risk increasing the message size to carry the extra bits in each block.</p> <p>If you determine your business needs the data to be encrypted, consider using AES in <a href="https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Counter_.28CTR.29">CTR</a> mode to generate stream cypher bits. Counter mode is practical for dealing with cases where reception can be unreliable and packets may be lost. You'll have to keep the counters synchronized, so be aware that periodically transmitting the counter's value will add to the overhead. And you'll have to reserve a few bytes of state to hold the counter, because reuse of an encrypted bit stream can lead directly to data recovery.</p>

|sensors|microcontrollers|power-consumption|product-design|

What is the power implication of encrypting my sensor traffic?

847

<p>Considering a typical type of application, a battery powered sensor taking readings (32 bit value) every 10 minutes, what is the likely impact on battery life if I choose a simple un-encrypted on-air protocol, compared with an encrypted transmission?</p> <p>Assume that my data isn't particularly secret, but according to <a href="https://iot.stackexchange.com/questions/554/is-there-any-advantage-in-encrypting-sensor-data-that-is-not-private">this question</a> I probably need to consider encrypting it, so long as there isn't actually a significant design cost.</p> <p>For simplicity, let's assume I'm using a <a href="https://www.nordicsemi.com/eng/Products/Bluetooth-low-energy/nRF51822" rel="nofollow noreferrer">nRF51822</a> SoC which supports a BLE stack and a simpler 2.4&nbsp;GHz protocol as well.</p> <p>Since I'm thinking of a commercial product application rather than a one-off installation, the encryption needs to be compute intensive to break (say at least $500 of 2016 cloud compute), rather than a simple obfuscation. Something that remains secure even with access to the device firmware.</p>

2017-01-21T11:15:22.370

<p><a href="https://github.com/alexa-pi/AlexaPi" rel="noreferrer">This open source Raspberry PI Alexa client</a> has support for free wake words made as easily from PI's terminal as:</p> <pre><code>sudo systemctl stop AlexaPi.service sudo nano /etc/opt/AlexaPi/config.yaml change line: phrase: "alexa" </code></pre> <p>See <a href="https://github.com/alexa-pi/AlexaPi/issues/222" rel="noreferrer">discussion</a>.</p>

|alexa|amazon-echo|hardware|

How can I detect Alexa's current state or change its current state with an external device?

853

<p>I want to have custom wake-word for Alexa so I want to interface this <a href="http://rads.stackoverflow.com/amzn/click/B00X4WHP5E" rel="noreferrer">Amazon Echo</a> with an external device. I am wondering if it is possible to create a proxy device that would wake up Alexa if I give voice command to the proxy device. More precisely it should be able to switch Alexa between its following <a href="https://developer.amazon.com/public/solutions/alexa/alexa-voice-service/content/alexa-voice-service-ux-design-guidelines" rel="noreferrer">states</a>.</p> <blockquote> <ul> <li><strong>Idle</strong>: When Alexa is idle, customers can use the Alexa wake word or a physical control to wake Alexa, which starts her listening state.</li> <li><strong>Listening</strong>: When Alexa’s microphone(s) have been activated, she is in a listening state and is waiting for voice input. </li> <li><strong>Microphone Off</strong>: On a voice-initiated implementation, the customer can block Alexa from activating by turning on microphone off mode, which physically powers down the microphones and (if available) camera.</li> </ul> </blockquote> <p>The idea is simple. The device would be capable of recognising words, just some words nothing too difficult.</p> <p>By default, it would keep Alexa in <strong>Microphone Off</strong> state, so it won't pick up voices from its environment.</p> <p>Now, when I want to use Alexa, instead of waking it up directly I would use my proxy, that would somehow enable Alexa's microphone and switch Alexa into <strong>Listening</strong> state.</p> <p>When Alexa goes back to <strong>Idle</strong> the proxy should automatically switch it to <strong>Microphone Off</strong> state.</p> <hr> <p>What I need in general are:</p> <ol> <li><p><strong>The proxy should know Alexa's current state.</strong> Won't be the best solution but I may can decide Alexa's current state using its attention system (its sound and LED signals are summarised <a href="https://developer.amazon.com/public/solutions/alexa/alexa-voice-service/content/alexa-voice-service-ux-design-guidelines" rel="noreferrer">here</a>). Is there any other way I can know Alexa's current state?</p></li> <li><p><strong>The proxy should be able to switch Alexa into a specific state.</strong> So how can I make Alexa to switch between its states using another device?</p></li> </ol> <p>It all comes down to what are the possibilities to interface an Amazon Echo / Dot (and Alexa) with another device?</p> <p>(I am interested in solutions using mechanical interaction as well.)</p>

2017-01-21T16:41:13.983

<p>I just recently discovered this issue while upgrading my SmartThings Hub to a newer model.</p> <p>It appears that newly added Hubs to your account <strong>do not</strong> have Insecure Rejoin enabled, but my older model did have this feature enabled. So, perhaps Samsung has updated their systems to protect the users.</p> <p>Below are screenshots showing how to review/change your configuration for this security feature. Starting from your location 'context menu':</p> <p><a href="https://i.stack.imgur.com/SEdoHm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SEdoHm.png" alt="Click the gear icon"></a><a href="https://i.stack.imgur.com/pB7Ipm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/pB7Ipm.png" alt="Scroll to your hub"></a><a href="https://i.stack.imgur.com/I5x2cs.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/I5x2cs.png" alt="Click on Zigbee Utilities"></a><a href="https://i.stack.imgur.com/yvYJSs.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yvYJSs.png" alt="Change setting"></a></p>

|security|samsung-smartthings|

Is "Insecure Rejoin" still enabled by default for Samsung SmartThings hubs?

854

<p><a href="https://www.blackhat.com/docs/us-15/materials/us-15-Zillner-ZigBee-Exploited-The-Good-The-Bad-And-The-Ugly-wp.pdf" rel="noreferrer">According to Cognosec</a>, there is a critical vulnerability with ZigBee (one of the protocols supported by the SmartThings hub) which allows attackers to gain access to a ZigBee network by abusing a feature called "Insecure Rejoin". <a href="https://community.smartthings.com/t/security-of-smartthings-ecosystem/30827/5" rel="noreferrer">This forum post</a> has an accessible yet detailed explanation of the issue for futher context.</p> <p>I found a section in the <a href="https://support.smartthings.com/hc/en-gb/articles/208201243-ZigBee-Insecure-Rejoin-FAQ" rel="noreferrer">SmartThings FAQ</a> about the issue, which seems concerning:</p> <blockquote> <p>The current ZigBee Home Automation 1.2 standard uses encryption to allow only authorised devices to join a home network. In order to allow some devices (like motion sensors) to drop off of, and then easily re-join the network (to preserve battery power), there is a feature known as “insecure rejoin” built into the standard. It has been shown, however, that in very specific cases this feature could potentially be used to gain unauthorised access to a ZigBee network.</p> </blockquote> <p>According to that FAQ, <strong>Insecure Rejoin is enabled by default</strong>. Is this true, and does it mean that virtually all SmartThings hubs are vulnerable to attack?</p>

2017-01-22T11:47:41.517

<p>Hue Restore App might help you.</p> <p><a href="https://play.google.com/store/apps/details?id=com.rrapps.huerestore&amp;utm_source=stackoverflow_iot" rel="nofollow noreferrer">Hue Restore</a>- Hue Restore let you save and restore all Philips Hue lights in your home with single tap. You can do this right from home screen of your phone with convenient home screen widget. You no more have to worry about those pesky power cycle resets because you can get back your favourite settings in a single tap.</p> <p>Disclaimer: I am developer of this app.</p>

|philips-hue|ac-power|

How can I stop my Philips Hue bulbs resetting to full brightness after a power cut?

857

<p>According to <a href="https://www.reddit.com/r/Hue/comments/42btfz/any_way_to_default_to_off_after_power_outage/czaz2y2/">this comment on Reddit</a>, Philips Hue bulbs reset to 100% brightness after any power interruption (e.g. a power cut, switching the physical light switch off then on, etc).</p> <p>This does seem like a useful safety feature, but it's not practical for lights in my bedroom; if there's a power outage and then the power comes back on, the lights switch back on at 100% brightness, waking me up again. For areas where the power supply occasionally has problems, this could be a really big problem - imagine being woken up multiple times per night if the power cuts out, even for a couple of seconds!</p> <p><strong>Is there any way I can prevent Philips Hue bulbs from returning to 100% brightness after a power reset?</strong> Official solutions or workarounds would both be helpful.</p>

2017-01-23T16:20:37.817

<p>The direct answer is no.</p> <p>Workaround 1: hardware interrupt that can be activated via app across a battery of devices; difficulty level: hard.</p> <p>Workaround 2: Since you can change the wake word of any echo device via the app and android phones have a variety of batch (tap macro) apps available, hypothetically speaking, you could create a macro that will go through each device in the Alexa app's list and change it's wake word to something other than your regular one. You can then create a second macro that would undo this. Difficulty level: medium.</p>

|amazon-echo|alexa|

Can I ask Alexa to turn off its microphone by voice command?

861

<p>Is it possible to <a href="https://developer.amazon.com/public/solutions/alexa/alexa-skills-kit/overviews/steps-to-build-a-custom-skill" rel="noreferrer">build a custom skill</a> that would be equivalent to pressing the microphone on/off button on the top of the Amazon Echo?</p> <p>I know from <a href="http://www.howtogeek.com/237397/how-to-stop-your-amazon-echo-from-listening-in/" rel="noreferrer">this article on How-To Geek</a> that such voice command is not available by default:</p> <blockquote> <p>One feature we found missing, and surprisingly so given that the whole appeal of the Echo is voice control, is the inability to turn off the microphone via voice command. If you issue a command to Alexa like “Alexa, turn off the microphone” she’ll cheerily announce that there are no connected home devices that fit that description and give you instructions on how to set up the connected home features of the Alexa/Echo system.</p> </blockquote> <p>Does this mean this feature is also unavailable via API calls as well?</p> <p>And if it's not possible, why does Amazon not support this feature? </p>

2017-01-24T14:36:42.547

<p>In 2024, many heatpumps are C-Bus compatible. In my main home. I am using a C-Bus adapter that has rest calls. I found a handler and paid for it, so I didn't have to write the interface code for it.</p> <p>For my parents-in-law's house, I installed an <a href="https://aeotec.com/products/aeoteo-heavy-duty-switch/" rel="nofollow noreferrer">Aeotec Heavy Duty Switch</a>, it uses Z-wave. A couple of specs.</p> <ul> <li>Can power devices that draw up to 40 amps of power.</li> <li>Communicates outdoors over 150 metres / 490 feet.</li> </ul> <p>I have also used the same device at home to control my hot water heaters and the Spa and Pool pumps. For these, I just turn off power off to the whole gadget and stage them in, one at a time, to take advantage of solar power.</p> <p>Note - I am not associated with Aeotec in any way.</p>

|smart-home|smart-plugs|tp-link|

Can I use a smart plug with an air conditioning unit?

865

<p>I am hoping to be able to use a smart plug with my window air conditioner. I currently use the TP Link <a href="http://uk.tp-link.com/products/details/cat-5258_HS100.html" rel="noreferrer">HS 100</a> plugs around my home, but I am unsure if they could handle the amount of power an air conditioner uses. Any suggestions?</p>

2017-01-24T16:25:26.613

<p>You can use skills such as the <a href="https://rads.stackoverflow.com/amzn/click/com/B0716PNRXY" rel="nofollow noreferrer" rel="nofollow noreferrer">My Reader</a> skill, which can read any text you send to it through its servers.</p> <p>Once you have set it up, the steps are as follows.</p> <blockquote> <p><strong><em>How to use - Quick Start</em></strong></p> <ol> <li><p>Send the URL to 619-473-2337 (6194READER) from your phone by following steps for different browsers on your phone: <a href="https://s3.amazonaws.com/reader.help/How_to_Register_Phone_Number.pdf" rel="nofollow noreferrer">https://s3.amazonaws.com/reader.help/How_to_Register_Phone_Number.pdf</a></p></li> <li><p>In a few seconds, you will receive message with an article index number, total chapter count and the article title.</p></li> <li><p>Launch the skill: “Alexa, ask My Reader to read.”</p></li> </ol> </blockquote> <p>There are a number of other skills which do a similar function, such as <a href="https://rads.stackoverflow.com/amzn/click/com/B07GSYW3S7" rel="nofollow noreferrer" rel="nofollow noreferrer">Text to Voice</a>, depending on what exactly you'd like to do.</p>

|smart-home|amazon-echo|alexa|

How to read custom documents by Alexa?

866

<p>According to <a href="https://www.amazon.com/gp/help/customer/display.html?nodeId=201975870" rel="nofollow noreferrer">Amazon</a>, Alexa can read certain Kindle books.</p> <blockquote> <p>Alexa reads Kindle books eligible for Text-to-Speech (an experimental reading technology that allows supported Amazon devices to read Kindle books aloud). </p> </blockquote> <h2>Concept</h2> <p>If it is possible I want to use this feature but instead of reading Kindle books, Alexa should read custom texts or reports made by some smart-home devices. So during the day different devices would report different events like:</p> <ul> <li>Temperature sensor: <code>New "highest temperate ever measured": 30 °C.</code></li> <li>Connected dog-feeder: <code>The dog food container is empty.</code></li> <li>Some kind of sensor: <code>This happened while you was away and you should know about.</code></li> </ul> <p>Basically a service would collect all the data from the sensors and would create a report file that could be used with Alexa like:</p> <ul> <li>Alexa, read 'Afternoon home report'.</li> <li>Alexa, read 'Morning home report'.</li> </ul> <p>(So I could ask Alexa at the end of the day "What happened today?" and it could tell me by reading the reports.)</p> <h2>Problems</h2> <p>The reports should be in a correct format to make them eligible for Alexa to read them. I found something about it on Amazon forum, <a href="https://www.amazon.com/forum/kindle?_encoding=UTF8&amp;cdForum=Fx1D7SY3BVSESG&amp;cdThread=Tx21T5B0Y0UWZSY" rel="nofollow noreferrer">Can I enable Text to Speech on any personal document?</a></p> <blockquote> <p>Only if that document will open in the Reading App. Word documents, for instance, that have to be opened in a Word Process app or PDFs that have to opened in a PDF Reader can't use the Text to Speech feature.</p> <p>All documents in a Kindle compatible format should have Text to Speech available but I send all mine via the Amazon Cloud and Amazon converts them to the Kindle format. A tap in the center of the screen reveals the "Play" icon in the bottom left hand corner.</p> </blockquote> <p>Also I found an app on Amazon which called "<a href="https://rads.stackoverflow.com/amzn/click/B0073TZ1AA" rel="nofollow noreferrer">Pdf to Speech</a>" and Amazon's <a href="https://kdp.amazon.com/help?topicId=A3IWA2TQYMZ5J6#kindlegen" rel="nofollow noreferrer">Kindle Direct Publishing</a> tool "KindleGen v2.9", but still unclear how it should be done.</p> <h2>Possible solution</h2> <p>One way I have found on <a href="https://www.reddit.com/r/amazonecho/comments/553vm4/how_do_we_get_our_echo_to_read_pdfs/" rel="nofollow noreferrer">Reddit</a> describes the following:</p> <blockquote> <p>You don't need a kindle device, but you will need to download the kindle app. This gives you a special kindle address, to which you'd mail the PDF, which puts it in your kindle library.</p> <p>I have several devices, each loaded with the kindle app. So I have several kindle addresses, one per device (me-ipad@kindle, me-nexus@kindle, etc).</p> <p>The good news: once you email it, the PDF lives in the Kindle Cloud, so it's accessible to all...... <a href="https://www.amazon.com/gp/sendtokindle/email" rel="nofollow noreferrer">Amazon related Kindle page</a></p> <p>To have Alexa read it: 1) open Alexa app, go to books, tap desired book; or 2) Alexa, read (title) ..... <a href="https://www.amazon.com/gp/help/customer/display.html?nodeId=201975870" rel="nofollow noreferrer">Amz related Alexa page</a></p> </blockquote> <hr> <p>All in all, is this Kindle compatible format is actually <code>.mobi</code>? What steps should I perform to make the reports available by Alexa? (I would like to avoid the e-mailing stuff first if possible.)</p>

2017-01-24T18:20:42.910

<p>Rather a lot of personal information is collected, according to the <a href="http://shealth.samsung.com/policy" rel="noreferrer">Privacy Policy</a>. Here are some of the more sensitive pieces of information collected:</p> <h3>When not logged in</h3> <ul> <li>Birth year</li> <li>Gender</li> <li>Height, weight and activity levels</li> <li>Device identifiers</li> </ul> <h3>When using 'Enhanced Features'</h3> <ul> <li>Phone number</li> <li>Nickname, profile image, birthday and country</li> <li>Steps, burned calories, distance, activity logs</li> </ul> <h3>When logged in</h3> <ul> <li>Device identifiers for any accessories</li> <li>Information about exercise routines</li> <li>Heart rate, ECG, body fat, skeletal muscle, muscle mass, basal metabolic rate, blood glucose level, blood pressure level, blood oxygen (SpO2) level, hemoglobin (HbA1c) level, stress level and sleep-related information.</li> </ul> <p>As you can see, with all those data points, someone could get a clear picture about your health, activity and location. Samsung even admit in the Privacy Policy:</p> <blockquote> <p>Please note that such wellness-related information can reveal your state of health and can therefore consist of sensitive personal data.</p> </blockquote> <p>However, I'm not surprised or even upset that Samsung collects that information; without collecting it, the fitness tracking wouldn't work very well at all.</p> <p>Samsung are a little vague about <em>where</em> the information is stored:</p> <blockquote> <p>We use a variety of standard security measures, including encryption and authentication tools. When you access information, we offer the use of a secure server.</p> </blockquote> <p>Your guess is as good as mine!</p> <p>If you're not comfortable with this, European data protection regulations help a lot:</p> <blockquote> <p>You may also have statutory rights to access and edit such information and you have the right to request information about your personal data. Furthermore, you may refuse the disclosure of your information to a third party at the moment the information is collected. If you have any questions about the information we hold, please contact our customer service department at <a href="http://help.content.samsung.com" rel="noreferrer">http://help.content.samsung.com</a> or the European Data Protection Officer, Samsung Electronics (UK) Limited, Samsung House, 1000 Hillswood Drive, Chertsey, Surrey KT16 0PS.</p> </blockquote> <p>Not convenient, but <strong>in theory</strong>, you can ask Samsung to stop collecting data at any point, or request all of the information they have on you.</p>

|privacy|wearables|

Are Samsung's "S Health" devices storing health data in the cloud?

868

<p>Samsung wearables like the Gear watches can run the Android app <a href="https://play.google.com/store/apps/details?id=com.sec.android.app.shealth" rel="noreferrer">S Health</a> are advertised to be quite secure and can be run by using the Samsung Knox security feature which is in itself advertised as certified by government agencies and so forth.</p> <p>However there seems to be no easily available information if my health data is just securely stored on the device or if it's automatically stored on a cloud storage as well.</p> <p>This section from the App description seems to point to a rather free usage of at least the step count.</p> <blockquote> <p>Compete with your friends and check your ranking. You can compete with your friends in the address box once your Samsung account is registered. On "together" section, you can select your own competitor and compare your steps with people of different age group across the globe. </p> </blockquote> <p><strong><em>Which data of S Health devices is stored where and how can I control it?</em></strong></p>

2017-01-24T18:21:10.427

<blockquote> <p>If I ever wanted to sell the Echo, it'd be useful to know what information is on the device, so that I can try to remove it.</p> </blockquote> <p>I think one good option is to deregister the echo device from you Amazon account as <a href="https://www.youtube.com/watch?v=CbwvsU8HnrY" rel="nofollow noreferrer">this</a> video guide shows.</p> <p>Here are the steps:</p> <ol> <li>Go to the Alexa app.</li> <li>Click 'Settings'.</li> <li>Select the device that you want to deregister.</li> <li>Scroll to <em>'Device is registered to ...'</em>, and click 'Deregister'.</li> <li>Confirm that you want to deregister when the modal pops up.</li> </ol>

|amazon-echo|privacy|

What personal information is stored on my Amazon Echo?

869

<p>As far as I can tell, <em>most</em> data from the Amazon Echo (e.g. recordings of my commands) are stored in the cloud, according to the <a href="https://www.amazon.com/gp/help/customer/display.html?nodeId=201602230" rel="nofollow noreferrer">Alexa FAQ</a>. However, I couldn't find any authoritative information about what information <strong>is</strong> stored on the device itself.</p> <p><a href="https://iot.stackexchange.com/questions/357/is-the-amazon-echo-always-listening-and-sending-data-to-the-cloud">A previous question I asked</a> suggests that short snippets of sound are stored on the Echo itself so that the wake word can be detected, but apart from that, I'm not sure.</p> <p>If I ever wanted to sell the Echo, it'd be useful to know what information <strong>is</strong> on the device, so that I can try to remove it. </p> <p><strong>What <em>personal</em> information is stored on the device itself (not in the cloud)?</strong> Amazon login credentials? Cached data from skills?</p>

2017-01-25T14:55:01.570

<p>Have to start out by saying, this will have to take place on the router. I looked into the camera, but it simply seems to be too manufacturer set to be able to run a crack that complex on. Perhaps if you did some firmware replacement you could manage, but not simply.</p> <p>With your particular router, it appears that you can. I don't actually have your router, so I could be reading the documentation wrong, but it appears that you should be able to. IF I'm reading right, follow these steps: (adapted from <a href="https://www.cosmote.gr/fixed/documents/10280/87751345/Speedport_Entry_2i_Maintenance_Management_EN_v_2_1.pdf/e5aa9ed9-8e66-4d3b-8283-b79d67e0ded9">cosmote documentation</a>)</p> <ol> <li>Go under <code>Internet &gt; Security &gt; Filter Criteria.</code></li> <li>Select the radio button <code>on</code> beside <code>URL filter.</code></li> <li>Select <code>New Item.</code></li> <li>Type in any name and the IP of your camera and Apply.</li> <li>Click <code>IP filter - IPV4</code> to open the IPV4 filters page.</li> <li>Edit the settings under Destination IP and Source IP range to match your requirements.</li> </ol> <p>I could be wrong, but that appears to be the method. :) You might have to apply multiple rules to rule out all but the IP's you want: I'm not sure.</p> <p>If you are unable to block all traffic except the IP you want on your router, the answer is, <strong>no, it is not possible, short of buying a new router.</strong></p> <p>Hope it works!</p>

|smart-home|security|privacy|digital-cameras|whitelisting|

How can I set up IP whitelisting on an IP camera without support for whitelists?

873

<p>The camera in question is a <a href="http://rads.stackoverflow.com/amzn/click/B01C6DXMX0" rel="nofollow noreferrer">Ring Stick Up Cam</a>. I want to add an additional layer of security and prevent anyone from peeking (listening) into my home.</p> <p>I thought that it might be good if I could set up some kind of IP whitelist, so only requests from authorized sources would get through towards the camera.</p> <p>I have a ZTE Speedport Entry 2i router + modem by my Internet provider (<a href="http://www.telekom.hu/static-la/sw/file/speedport_entry_2i_hasznalati_utmutato.pdf" rel="nofollow noreferrer">Hungarian manual</a> just for the picture) (<a href="https://www.cosmote.gr/fixed/documents/10280/87751345/Speedport_Entry_2i_Maintenance_Management_EN_v_2_1.pdf/e5aa9ed9-8e66-4d3b-8283-b79d67e0ded9" rel="nofollow noreferrer">English manual</a> it seems to be the same device).</p> <p>Is this a reasonable idea and if so how could someone set up such service for an IP camera?</p>

2017-01-25T18:31:33.000

<p>According to the FitBit community, the GPS is only enabled when you have turned on a tracking activity, example, walking, hiking, biking, etc. From the <a href="https://community.fitbit.com/t5/Surge/How-do-I-turn-off-the-GPS-on-my-Surge/td-p/940377" rel="nofollow noreferrer">Fitbit Community</a>:</p> <blockquote> <p>GPS is only when you are tracking an activity that uses GPS, such as hiking. As soon as you stop tracking that activity GPS is turned off.</p> </blockquote> <p>and</p> <blockquote> <p>By design, it should only turn on when you have started an (outdoor) exercise using the controls on the Surge - that means, Run, Free Run, Walk, Hike, Bike, or Golf. If you haven't started one of those exercises, there wouldn't even be a way of telling if the GPS is on or not.</p> </blockquote> <p>In other words, to keep the GPS off, just don't run any of those controls. If you want to have a hike registerd, just put it in "work out" mode and rename it as a hike later. (From the <a href="https://community.fitbit.com/t5/Surge/Turning-Off-GPS-in-Surge/td-p/631317" rel="nofollow noreferrer">FitBit community</a>)</p>

|privacy|gps|fitbit|

How do I stop the Fitbit Surge from storing GPS data?

875

<p>I was reading about the privacy of Fitbit devices, and <a href="http://www.huffingtonpost.com/mark-weinstein/what-your-fitbit-doesnt-w_b_8851664.html" rel="noreferrer">this Huffington Post article</a> has a rather concerning point with regard to GPS-enabled fitness trackers:</p> <blockquote> <p>In certain cases, the government or legal institution could request your fitness tracker information and then use it against you in a court of law. That’s what happened to Chris Bucchere, a San Francisco cyclist who struck and killed an elderly pedestrian. Bucchere was charged with felony vehicular manslaughter, carrying a potential penalty of six years in prison. Prosecutors obtained his data from his GPS-enabled fitness tracker to show he’d been speeding before the accident. Bucchere’s self-monitoring became a piece of evidence against himself due to a lack of privacy. This is not to condone Bucchere — clearly he committed a crime — rather this just illustrates one example of surprising use cases for what you might think is harmless personal data.</p> </blockquote> <p>Clearly, I would rather not have my GPS location recorded at all times, in case the data gets hacked or given to anyone without my permission. The <a href="https://www.fitbit.com/uk/surge" rel="noreferrer">Fitbit Surge</a> is one of these GPS-enabled fitness watches - <strong>how can I disable GPS tracking and clear any information they have on me?</strong> Is the GPS data also synchronised to the cloud?</p>

2017-01-26T13:46:04.517

<p>Looking at ease of programming and low cost, I would probably start with some kind of Arduino module (or low-cost clone). Code for your ultrasonic sensor already exists, as does example code for ZigBee, for example using the Digi XBee modules. On the latter, you connect the XBee to a serial port, and after making the connection with the venerable old "AT" command interface, you then have a point-to-point channel that you can send any text down (to your Raspberry Pi). ZigBee is not the cheapest type of short-range communication, but the XBee modules have fallen in price in real terms over the last 5 years.</p> <p>I know that some people have a problem with the C/C++ based language used on Arduino, but in this case you'd largely be merging together already existing scripts from other users. </p> <p>If you Google around for "Arduino sleep mode", you'll find examples of how you can put the Arduino into low power mode, and wake up sporadically to take a reading, communicate it, then re-enter sleep mode.</p>

|microcontrollers|hardware|zigbee|

Selecting a microcontroller for a battery operated data collection project

880

<p>I am planning to measure water level in a well, which is about 10 m deep with maximum water level up to 5 m. My plan is to use ultrasonic sensor <a href="http://www.micropik.com/PDF/HCSR04.pdf" rel="noreferrer">HC SR04</a> to measure depth, transmit it via ZigBee to a Raspberry Pi inside my home.</p> <p>As discussed in my <a href="https://iot.stackexchange.com/questions/686/connecting-a-sensor-to-zigbee" title="previous question">previous question</a> I need to select a micro controller to connect the ultrasound sensor and the ZigBee module together. </p> <p>The parameters for selection is:</p> <ol> <li><p>Low power: I am planning to run this on battery, so low power usage is a priority. As of now I do not have any target for power usage or days between battery changes or even which battery to use. Since this is more of a learning project and it's in my home, I am flexible, but lower power usage is better.</p></li> <li><p>Low cost: This is a learning project for me, and I do not want to spend an outrageous amount of money on this, so lower cost is better.</p></li> <li><p>Working inside a well: The whole project will be working from inside a well and will be exposed to harsh sunlight and rain. I will be providing a good case and protection though.</p></li> <li><p>Easy to program.</p></li> </ol> <p>I chose ZigBee as it is simple, meets my use case and low power. But my requirement is to transport the sensor data and I am open to other transports. The distance from my well to Raspberry Pi is about 6 meters with a wall in between. I am planning to measure the water depth every 10 minutes and twice a minute when the water pump is running (approx 20 minutes daily) .</p>

2017-01-26T17:27:47.000

<p>As time has passed on, I think the answer to this question now needs to be:</p> <p><strong>Yes, Alexa can speak without being prompted. Specifically, she can utter anything you want her to!</strong></p> <p>The convenient tool you can use is a shell script named <a href="https://github.com/thorsten-gehrig/alexa-remote-control" rel="nofollow noreferrer">alexa-remote-control</a>. A detailed documentation of the script is available in this <a href="https://blog.loetzimmer.de/2017/10/amazon-alexa-hort-auf-die-shell-echo.html" rel="nofollow noreferrer">blogpost</a>, although only in German.</p> <p>It relies on http POST requests to achieve things like playing music, radio, activating the daily briefing and letting your Echo devices speak any text you want them to.</p> <p>The text-to-speech feature can be used in Linux, e.g., by executing this command in a terminal: </p> <pre><code>alexa_remote_control.sh -d "Your Echo's name" -e speak:'Welcome back buddy!' </code></pre> <p>I use it frequently within Node-Red running on a Raspberry Pi, e.g. to issue warnings once some sensor reading moves outside its normal range. </p>

|alexa|

Can Alexa ever speak without being prompted?

882

<p>I was recently asked if Alexa can ever speak without prompting, so I thought it'd be helpful to ask here to make sure I'm right; as far as I know, Alexa will <em>never, ever</em> speak without the wake word, and the only unprompted sound it will make is the alarm sound.</p> <p><a href="https://techcrunch.com/2016/09/08/amazon-echo-could-soon-start-talking-to-you-unprompted/">This TechCrunch article</a> seems to agree that there isn't any way to make Alexa speak unprompted, but it doesn't mention Alexa skills at all; is there perhaps some API available to them which isn't yet used?</p> <p>Many people seem to be interested in this so that they can get Alexa to say certain phrases, such as perhaps an alert if the doorbell is ringing, or some way of indicating an event has happened.</p> <p><strong>Can Alexa speak without first being prompted by either the wake word, tap-to-talk or push-to-talk (depending on the device)?</strong> I'm excluding alarms for the purpose of this question, but solutions using custom skills are fine.</p>

2017-01-26T21:11:48.920

<p>Many vendors have bad security practices and ship <em>all</em> their devices with an <strong><em>identical</strong> default password</em> (which is easier than programming and labeling each device with a unique password or mandating a password change before it can be used).<br> When such devices are accessible online it becomes trivial to find them and use such default credentials to abuse them at scale. </p> <p>The fact that you make effort to <strong>change the default password</strong> is already sufficient to thwart a large part of that potential abuse, <em>almost</em> regardless of the actual strength of the password you select. </p> <blockquote> <p>Is it okay to come up with one very secure password to use on all my devices?</p> </blockquote> <p>Re-using the same password in many places is universally a bad idea. </p> <p>The main problem is that good security is hard and you can't really tell from the outside if your really good password will be properly secured or not, at least not until the moment that it becomes clear that the security failed, or there was never any security in the first place. </p> <p>For instance even the best password in the world is useless if the device/application/website will effectively hand over that password, in clear text, when asked correctly. It would be especially bad if that password can then subsequently be used to unlock many more devices/applications/sites/secrets. </p> <p>If you don't have a password manager already and don't want one either simply labeling devices with a unique password is quite effective and secure against digital attacks, as is an old fashioned notebook.</p>

|security|

Should I use a different password on each IoT device?

885

<p>According to <a href="http://www.cmswire.com/cms/internet-of-things/top-5-internet-of-things-security-concerns-026043.php" rel="noreferrer">cmswire.com</a>, one of the major security risks with the Internet of Things is Insufficient Authentication/Authorization. When it comes to the Internet of Things, should I use a different password for each of my devices, or is it okay to come up with one very secure password to use on all my devices?</p> <p>More specifically, if I have bought multiple iterations of the same device, should I come up with a different password for each one?</p>

2017-01-27T10:47:01.973

<p>Creating a startup is not about what you can do with the technology and not even about the product. For a successful startup that can captivate VC's you should first think about the market that you are going to serve. But thinking about the market you will serve is not enough. You need to have real data about the market. It is not just about something that makes sense to you. Creating a product and then tying to sell it is not a successful approach and that is the way most unsuccessful startups end. A market is a REAL NEED. When you crate a product create it to address a specific Market. This is what makes a successful product, a product that sell itself because people are already looking for it. VC's invest only on startups that have such products especially if they are already selling. </p> <p>To chose a technology to develop your product first you need to know what your product needs to do, this is how is it going to solve the problem in the selected Market. Then look at what the potential customers are willing to pay for it. Then chose the technology which allows the fastest time-to-market while keeping the cost within the budget. Then outsource the development or get a partner that can do it and is willing to work with you. Share the profits 50/50 with your partner. Then when you have a prototype, start laying-out your business plan and remember that you can only captivate VC's if you show them how they can make money.</p> <p>If you need to lower the cost of your product for mass production you can use lower level languages and less resourceful micro-controllers like Microchip PIC or Silicon Labs EFM with ASM/C/C++. If the product is not going for mass production (100k+) use a higher level language and more resourceful micro-controllers, like Micro Python or Lua with ARM32 MIPS, or even Linux with ARM32/64. This saves on the development costs but increases the price of the hardware. Remember, the price of the product is not just a PCB with components; development, housing, packing and everything else necessary to sell the product should go into it's cost. Put that in the business plan. And don't go to a VC with an Arduino or a Raspberry pi or an Onion or any thing that looks like a hobbyist gadget, make a proper PCB with your logo on it and use a nice housing to make it look like a final product, VC's rarely trust hobbyist gadgets.</p> <p>Start up, not down, and best of lucks.</p>

|microcontrollers|hardware|

Which microcontroller and programming language should I use for an Internet-enabled weather display?

891

<p>I am a newbie in IoT and want to start my career in IoT. As I search on Google for startups in IoT, I found many blogs. And I found the languages used in IoT like C#, Java, Node.js, and the microcontrollers like Arduino, Raspberry Pi, Intel, Netduino, etc.</p> <p>As I am new to IoT I don't know which language is best and which microcontroller I use for a startup? </p> <p>For the basic startup I say, I want to create a device that have the display that show the weather for the location given from my mobile. So it may be a good example for startup that covers the hardware, Internet and the software.</p> <p>Device will be a battery-powered, a small digital display and yes cost restriction. </p> <p>Which microcontroller and language should I use that fulfils my requirements for showing the weather?</p>

2017-01-27T13:45:02.467

<p>There are two reasons. </p> <p>(1) <strong>First is simpler, end-to-end connectivity</strong>. If both source and destination have public IPv4 (or IPv6, of course) address, they can connect to each other in any direction anytime.</p> <p>Your IoT with private IP <code>192.168.0.52</code> however can use <a href="https://en.wikipedia.org/wiki/Network_address_translation" rel="noreferrer">NAT</a> ONLY to connect to any public IP on the Internet whenever it wants, but the rest of the Internet cannot connect to it. There were kludges like <a href="https://en.wikipedia.org/wiki/DNAT" rel="noreferrer">DNAT</a> and <a href="https://en.wikipedia.org/wiki/Upnp" rel="noreferrer">uPNP</a> that used to allow you to specify that some incoming connections are enabled, but they are breaking more and more nowadays due to implementation of <a href="https://en.wikipedia.org/wiki/Carrier-grade_NAT" rel="noreferrer">CGNAT</a> because of IPv4 shortages.</p> <p>A common (so-called) "solution" to this problem is that all your (NATed) devices connect to some central location with public IP (usually hosted by the manufacturer of device). This makes it work technically, but involves a <strong>privacy</strong> issue (you're giving all the data from your IoTs), <strong>security</strong> issue (as you're wide open to them, breach or disgruntled employee can do anything your IoT device can do and access), and <strong>reliability</strong> issue (when the manufacturer goes out of business or decides to stop supporting old devices or is suffering outages) all your (and everybody elses) perfectly functional devices will stop working.</p> <p>(2) <strong>second problem is that it will stop working anyway</strong> (even for outgoing connections) some time in the future (not in a year or two, but still. The more IoT and services catch on, the sooner it will start breaking).</p> <p>That is because NAT allows private addresses like <code>192.168.0.52</code> to reach the Internet at large. It does that by changing source address <code>192.168.0.52</code> to public IP of your router, but replaces source port with free one from the pool. </p> <p>For example, your first connection might be <code>192.168.0.52:1000</code> might be <a href="https://en.wikipedia.org/wiki/Carrier-grade_NAT" rel="noreferrer">(CG)-NATed</a> to (public IP) <code>198.51.100.1:1000</code>, and your neighbour <code>192.168.0.77:1000</code> might get NATed to <code>198.51.100.1:1001</code>. Your second connection from <code>192.168.0.52:1001</code> would then be NATed to <code>198.51.100.1:1002</code> etc.</p> <p>Problem is, even simple stuff like opening a web page will likely open dozens of connections and use a dozen of ports (for DNS queries, HTTP(S) connection for different elements, JS analytics on different sites etc). </p> <p>More expensive programs, like torrent clients, will easily use up a <strong>thousands of ports</strong>. And there is only <strong>65535</strong> ports available for any IP.</p> <p>Which means several of your neighbours sharing the same CGNAT IP use a bigger share of connections (and more IoTs will mean more connections), and suddenly all of 65535 ports on that public IP 198.51.100.1 are used. Which means no new connections can be established for you and your neighbours. Which on bigger scale means lots people are cut from their IoTs, and civilisation as we know it collapses :-)</p> <p>Since we would like to delay this civilisation collapse as long as possible, we're transitioning to <a href="https://en.wikipedia.org/wiki/IPv6" rel="noreferrer">IPv6</a> instead. Please support continued existence of this civilisation by <a href="http://ipv6actnow.org/" rel="noreferrer">using IPv6 if possible</a>. Thanks!</p>

|ip-address|

Why would IPv6 be necessary for the IoT?

894

<p>I recently ran across this quote from <a href="https://securityintelligence.com/the-importance-of-ipv6-and-the-internet-of-things/" rel="noreferrer">Security Intelligence</a> about the Internet of things and IPv6:</p> <blockquote> <p>Analysts predict that there will be 30 billion connected “things” by 2020, yet the IPv4 address space only accommodates 4 billion and change. Even with network address translation (NAT) and private address space, the IoT’s appetite for addresses will overcome IPv4’s ability to sate it.</p> <p>Enter IPv6, which expands the address space to 340 undecillion, or 3.4×10³⁸. Well, it’s technically a bit less than that, since some combinations are reserved; nonetheless, that’s still enough usable addresses to allocate about 4,000 to every person on the planet.</p> </blockquote> <p>What puzzles me is why the Internet of Things would make any difference to the need to switch to IPv6. It seems to me that the vast majority of Things are connected to a router, hence a need only for one <em>world-wide</em> IP.</p> <p>For instance, your smart oven's (or whatever) IP is 192.168.0.52, that doesn't prevent your neighbour's Echo from having the same IP, because in order to access that IP from outside your home, you have to go through your <em>home's</em> IP address, ex: 148.238.24.9.</p> <p><strong>Why would the advent of IoT necessitate the switch to IPv6?</strong></p>

2017-01-27T21:22:28.993

<p>No, the connection will still be encrypted, but the services that depend on it like WPS (Wireless Protected Setup) won't work. WPS is a simple way to setup the WIFI connection by pressing a button in the router after setting the connecting device into WPS mode, but when the SSID is not being broadcasted the device can't find it and WPS won't Work. The encryption mode is WPA or WPA2 not WPS.</p> <p>To connect without the SSID you will have to type the SSID manually everytime you want to set up a new connection. </p>

|security|networking|routers|

Will disabling my network's SSID broadcast cause my WPA encryption to be disabled?

902

<p>I encountered this message when I tried to disable the SSID broadcast of my home network. Does this mean that my router's Wi-Fi connection will no longer be encrypted? </p> <p><a href="https://i.stack.imgur.com/18Nar.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/18Nar.png" alt="Screenshot"></a></p> <p>Sorry I'm pretty new to networking but any help/guidance or further reading is much appreciated!</p>

2017-01-28T17:11:01.023

<p>Great question! As has been remarked in the comments, this sounds mostly like a news report rant that hasn't really researched completely. All the articles out there say essentially the same thing: no new research has been done to confirm suspicions, and all articles find their source (eventually) in a <a href="https://www.abiresearch.com/press/nest-cam-works-around-clock/" rel="nofollow noreferrer">single article by abiresearch.com</a>. That article in and of itself is lacking; as @jterrace suggested, it would be very simple to just test data transmission. However, none of these tests have been done.</p> <p>In other words, just from a surface glance, it looks not like an absolute scam, but like an insufficiently tested hypothesis which can't truly be proven from the information given. Furthermore, I ran into a few articles like <a href="https://www.slashgear.com/no-nest-cam-isnt-secretly-spying-on-you-25416086/" rel="nofollow noreferrer">this one from SlashGear.com</a>, which examines ABI's claims.</p> <p>These articles point out that ABI has yet to explain why they feel that the current <em>ought</em> to drop when the camera is off. We tend to think of it something like a DVD machine or TV screen that turns on in response to Infra Red, but in reality, the Nest Cam functions nothing like the same.</p> <p>A TV only needs to have a small portion of its system booted up. However, the Cam <em>must</em> have the <strong>whole system</strong> booted up, so as to be able to receive information over the network (drawing electricity) and start the camera as quickly as possible (which is estimated to take <a href="https://www.slashgear.com/no-nest-cam-isnt-secretly-spying-on-you-25416086/" rel="nofollow noreferrer">45-60 seconds</a> from cold boot).</p> <p>The current staying at 340mA is not unusual: the camera must keep itself booted up and listening to the router. And according to their spokesman:</p> <blockquote> <p>When Nest Cam is turned off from the user interface (UI), it does not fully power down, as we expect the camera to be turned on again at any point in time. With that said, when Nest Cam is turned off, it completely stops transmitting video to the cloud, meaning it no longer observes its surroundings.</p> </blockquote> <p>So the answer is, <strong>no, as far as we can tell, the Nest Cam is <em>not</em> recording you when it's off.</strong></p>

|privacy|nest-cam|

Is the Nest Cam recording even when "switched off"?

906

<p><a href="http://www.theregister.co.uk/2015/11/25/nest_cam_doesnt_spy/" rel="noreferrer">The Register</a> have published an article suggesting that the Nest Cam could be recording even when told to switch off:</p> <blockquote> <p>Alphabet-owned Nest says there is no truth to the allegation that its internet-connected home CCTV cameras continue to record video even when switched off.</p> <p>This assertion comes after a report from ABI Research found that the Nest Cam keeps drawing a healthy amount of current even when told to turn off, suggesting it's still observing.</p> <p>According to the ABI Teardown report, the Nest Cam draws 343mA while off, and up to 370mA or 418mA while on, depending on the resolution of the video being streamed to the cloud.</p> <p>ABI vice president of teardowns Jim Mielke said that while most surveillance cameras would be expected to drop power consumption when moved to their off state, the Nest camera continues to suck juice.</p> </blockquote> <p><strong>Is there any evidence that the camera is continuing to record even when told not to, or does power usage simply remain high because it's connected to the network waiting for the 'turn on' command?</strong></p>

2017-01-30T13:16:41.260

<p>Mirai's source code <a href="https://krebsonsecurity.com/2016/10/source-code-for-iot-botnet-mirai-released/" rel="noreferrer">has been released in public</a>, and <a href="https://github.com/jgamblin" rel="noreferrer">Jerry Gamblin</a> has kindly <a href="https://github.com/jgamblin/Mirai-Source-Code" rel="noreferrer">created a GitHub repository</a> so that you can easily look through the code for research/academic purposes such as this.</p> <p>I think you'll get the most authoritative answer by dissecting the code to find out how Mirai finds its targets, so I had a little look around and here's what I found:</p> <ol> <li><p>There are <a href="https://github.com/jgamblin/Mirai-Source-Code/blob/master/mirai/bot/scanner.c#L124-L185" rel="noreferrer">61 unique username/password combinations that Mirai is programmed with (these are hard-coded)</a>.</p></li> <li><p>The scanner searches only on a <a href="https://github.com/rosgos/Mirai-Source-Code/blob/master/mirai/bot/scanner.c#L674-L704" rel="noreferrer">limited set of subnets to find targets</a>. These are: 127.0.0.0/8, 0.0.0.0/8, 3.0.0.0/8, 15.0.0.0/7, 56.0.0.0/8, 10.0.0.0/8, 192.168.0.0/16, 172.16.0.0/14 , 100.64.0.0/10, 169.254.0.0/16, 198.18.0.0/15, 224.<em>.</em>.*+, {6, 7, 11, 21, 22, 26, 28, 29, 30, 33, 55, 214, 215}.0.0.0/8. I've grouped the last set of blocks because these were all labelled as "Department of Defense" in the comments of the code.</p></li> <li><p>Mirai <a href="https://github.com/rosgos/Mirai-Source-Code/blob/master/mirai/bot/scanner.c#L200-L235" rel="noreferrer">performs</a> a rather primitive <a href="http://searchnetworking.techtarget.com/definition/SYN-scanning" rel="noreferrer">SYN scan</a> to try and find if any ports are open. If you're not familiar with how SYN scans work, they essentially involve sending a TCP <strong>SYN</strong> packet, which is the normal process of starting a TCP connection. The attacker then waits in hope of receiving a SYN-ACK packet, which would confirm that the target is listening on the specified port. You can read more about the process <a href="https://en.wikipedia.org/wiki/Transmission_Control_Protocol#Connection_establishment" rel="noreferrer">on Wikipedia</a>.</p></li> <li><p>Any targets that respond with a SYN-ACK are <a href="https://github.com/rosgos/Mirai-Source-Code/blob/master/mirai/bot/scanner.c#L237-L294" rel="noreferrer">added to a list of potential victims</a>.</p></li> <li><p>Mirai selects a password to try <a href="https://github.com/rosgos/Mirai-Source-Code/blob/master/mirai/bot/scanner.c#L885-L899" rel="noreferrer">semi-randomly</a>, using some sort of weighting system and attempts to <a href="https://github.com/rosgos/Mirai-Source-Code/blob/master/mirai/bot/scanner.c#L372" rel="noreferrer">connect using that</a>.</p></li> <li><p>Mirai then <a href="https://github.com/rosgos/Mirai-Source-Code/blob/master/mirai/bot/scanner.c#L449" rel="noreferrer">monitors to check if its connection was successful</a></p></li> <li><p>If the connection times out or something goes wrong, <a href="https://github.com/rosgos/Mirai-Source-Code/blob/master/mirai/bot/scanner.c#L317" rel="noreferrer">Mirai retries for a maximum of 10 attempts</a>.</p></li> <li><p>If all of this succeeds, tough luck. Your device is now <strong>infected</strong> until it restarts!</p></li> </ol> <p>So, in summary, to answer your question, <strong>yes, the version of Mirai known publicly will be defeated if you change the username and password</strong>. Anyone who modified their copy of Mirai could have added additional attack vectors though, although you might not class that as the same malware type any more.</p>

|security|privacy|mirai|

Will changing my user name and password block Mirai attacks?

911

<p>I've recently been reading about <a href="https://www.incapsula.com/blog/malware-analysis-mirai-ddos-botnet.html" rel="noreferrer">Mirai</a>, malware whose source has been revealed which is designed to infect IoT devices. It is appears to be a serious threat to security compromised Internet of Things devices. According to <a href="https://en.wikipedia.org/wiki/Mirai_(malware)" rel="noreferrer">Wikipedia</a>:</p> <blockquote> <p><strong>Mirai</strong> (Japanese for "the future") is malware that turns computer systems running Linux into remotely controlled "bots", that can be used as part of a botnet in large-scale network attacks. It primarily targets online consumer devices such as remote cameras and home routers. The Mirai botnet has been used in some of the largest and most disruptive distributed denial of service (DDoS) attacks, including an attack on 20 September 2016 on computer security journalist Brian Krebs's web site, an attack on French web host OVH and the October 2016 Dyn cyberattack.</p> </blockquote> <p>The article (and others I have read online) shows that Mirai makes the attack by grubbing the internet for devices that are using factory default usernames and passwords from a database. Is it enough, then, to simply change your username and password on an IoT device? Will that protect it from the Mirai attack, or does Mirai have other methods of making it in?</p> <p><strong>Note: I am not asking how to tell if my devices are infected: I am asking whether changing the password is adequate to prevent infection.</strong></p>

2017-01-30T20:22:25.757

<p>It seems like that is what Amazon intended. Since you are being credited for the purchase of the device, it is no loss to you and only to Amazon and the Earth itself (waste and whatnot)</p> <p>However, there is a new model coming out on Friday, February 3 which will last twice as long as the original.</p>

|batteries|amazon-iot-button|

What can I do when the AWS IoT Button runs out of charge?

918

<p>The <a href="https://aws.amazon.com/iotbutton/" rel="nofollow noreferrer">AWS IoT Button</a> (<a href="https://rads.stackoverflow.com/amzn/click/com/B01C7WE5WM" rel="nofollow noreferrer" rel="nofollow noreferrer">Amazon link</a>) is intriguing, but I saw something quite concerning in <a href="https://aws.amazon.com/iotbutton/faq/" rel="nofollow noreferrer">the FAQ</a>:</p> <blockquote> <p><strong>How long will the battery last?</strong></p> <p>The battery should last for approximately 1,000 presses. When the device battery runs out of charge, there is no way to recharge or replace the battery.</p> </blockquote> <p>The battery life is reasonable, but what am I supposed to do when the battery runs out? For a $20 button (which is already expensive!), it seems odd that there is no solution when the battery dies.</p> <p><strong>Does Amazon want you to throw away the old device and replace it when the batteries are out of charge?</strong> Is it replaceable in any way, or is the battery permanently connected to the device in a way that it's impossible to replace?</p>

2017-02-01T15:01:37.127

<p>If you are sure about using ARM then you could have a look at <a href="http://www.keil.com/support/man/docs/rlarm/rlarm_tn_poll_drv.htm" rel="nofollow noreferrer">Keil's Ethernet Drivers for ARM</a>. It is quite promising.</p> <blockquote> <p>RL-TCPnet includes several Ethernet Network drivers. These are located in the \Keil\ARM\RL\TCPnet\Drivers directory:</p> <ul> <li>LAN91C111.C - for the SMSC LAN91C111 Ethernet Controller used on the Phytec phyCore LPC229x evaluation board.</li> <li>EMAC_SAM7X.C - for the Atmel AT91SAM7X on-chip EMAC Ethernet Controller used on the Atmel AT91SAM7X-EK evaluation board.</li> <li>STR9_ENET.C - for the ST STR912 on-chip ENET Ethernet Controller used on the Keil MCBSTR9 evaluation board.</li> <li>LPC23_EMAC.c - for the NXP (founded by Philips) LPC2368 and LPC2378 on-chip EMAC Ethernet Controllers used on the Keil MCB2300 evaluation board.</li> <li>LPC24_EMAC.c - for the NXP (founded by Philips) LPC2468 and LPC2478 on-chip EMAC Ethernet Controllers used on the Keil MCB2400 evaluation board.</li> <li>LM3S_EMAC.c - for the Luminary Micro LM3S6962 and LM3S8962 on-chip EMAC Ethernet Controllers used on the Luminary Micro EK-LM3S6965 and EK-LM3S8962 evaluation boards.</li> </ul> </blockquote> <p>As you can see there are Ethernet Drivers examples for various evaluation boards that have different chips from different manufacturers. Like Atmel, NXP or ST Microelectonics.</p>

|networking|arm|drivers|ethernet|

What is a good reference for Ethernet Driver without an OS?

924

<p>Soon I will be working on an Ethernet implementation for a bare metal (no OS) capability on an ARM-based processor. I am somewhat familiar with the Ethernet driver model in the Linux Device Drivers book, but I'm wondering if there is a reference for implementing an Ethernet driver for a SoC run with a custom software stack.</p> <p>Are there any reference implementations for ARM architecture processors, or is there any guidance on how to implement an Ethernet driver on an ARM processor?</p>

2017-02-01T18:42:28.917

<p>If Internet connection is lost, BUT electricity is still on AND hub has battery working ok you may have chances to succeed. Since ZigBee connection is there you may have connection between hub and bulb.</p> <p>ZigBee is a technology for quite short distances, so if all works ok and then for example LAN can be used when in normal, then the distance between these two parts of your system becomes a signifigant factor. LAN works ok for long distance but same with ZigBee may be way too much.</p> <p>Answer to your question is that your setup will work, but be aware of the distance of hub and bulb.</p>

|networking|samsung-smartthings|philips-hue|

Can I control Philips Hue lights locally using Samsung SmartThings?

927

<p>SmartThings v2 Hubs <a href="https://support.smartthings.com/hc/en-gb/articles/209979766-Local-processing#Look" rel="nofollow noreferrer">can process some automations locally</a>:</p> <blockquote> <p>Some preconfigured automations can run locally.</p> <p>Manual, on-demand control of a device or SmartApp through the SmartThings mobile app always requires an internet connection to the cloud and cannot be performed locally.</p> </blockquote> <p>The documentation does not list which devices in particular are able to function without access to the Internet. Since the bulbs use ZigBee, it seems logical that they should be able to run locally, but I've heard people say that they had trouble with it.</p> <p><strong>Can Philips Hue bulbs be controlled locally if the hub's connection to the Internet is lost with automations?</strong></p>

2017-02-01T19:01:34.487

<p>From what I've found, it seems that some implementations (e.g. TI's <a href="http://www.ti.com/tool/z-stack" rel="nofollow noreferrer">Z-STACK</a>) recommend <a href="https://e2e.ti.com/support/wireless_connectivity/zigbee_6lowpan_802-15-4_mac/f/158/p/239001/836732" rel="nofollow noreferrer">refreshing the routing table every so often to avoid 'dead' nodes</a>:</p> <blockquote> <p>Yes, I waited 5 to 10 minutes. What is "some time"? I have seen cases where it takes a few minutes to recover. For example, if I cycle power on the gateway, it takes maybe a minute or two for the closest nodes to connect, then another minute or two for each successive level. But I waited much longer than this for the mesh to recover from this routing change.</p> <hr> <p>Yes, it might takes up to many minutes. So, if you want 5 or minutes, will your device come back? It is recommend to call NLME_RouteDiscoveryRequest() periodically to maintain the routing table.</p> </blockquote> <p>You can read more about what <code>NLME_RouteDiscoveryRequest()</code> does in the <a href="http://weber.itn.liu.se/~qinye29/tne090/Z-Stack%20Developer&#39;s%20Guide.pdf" rel="nofollow noreferrer">developer guide</a> (see page 11/12):</p> <blockquote> <p>The following figure shows an example of the many-to-one route discovery procedure. To initiate many-to-one route discovery, the concentrator broadcast a many-to-one route request to the entire network. Upon receipt of the route request, every device adds a route table entry for the concentrator and stores the one hop neighbor that relays the request as the next hop address. No route reply will be generated.</p> <p>Many-to-one route request command is similar to unicast route request command with same command ID and payload frame format. The option field in route request is many-to-one and the destination address is 0xFFFC. The following Z-Stack API can be used for the concentrator to send out many-to-one route request. Please refer to the ZStack API documentation for detailed usage about this API.</p> <p><code>ZStatus_t NLME_RouteDiscoveryRequest( uint16 DstAddress, byte options, uint8 radius )</code></p> </blockquote> <p><a href="https://ti.arc.nasa.gov/publications/2724/download/" rel="nofollow noreferrer"><em>Fault Tolerance in ZigBee Wireless Sensor Networks</em></a> is an interesting paper with some more information about how ZigBee networks tolerate node failure. It appears that the implementation used there reconstructed the network when one of the nodes was removed (the exact method of this is not clear, unfortunately), so that the malfunctioning node is no longer included in the mesh. In some cases, this led to sensors becoming 'orphaned' before requesting to rejoin the mesh network via a different route.</p> <p>In summary, from the resources I've found: <strong>it depends on your implementation, but most will re-evaluate the routing table reasonably frequently to avoid broken nodes from harming the network</strong>. I suspect you'll be able to get a more accurate response if you ask the vendor of your specific ZigBee implementation, since the exact operation will vary.</p>

|networking|power-consumption|zigbee|

Automatic link failure detection methods in ZigBee networks

928

<p>Given a ZigBee mesh network with several nodes in it. There are established links between each node via router nodes.</p> <p>If <strong>Node A</strong> wants to send a message to <strong>Node Z</strong> for the first time then <strong>Node A</strong> must perform a Route Discovery to determine which intermediate nodes will forward its message.</p> <p>The Route Discovery mechanism is described <a href="http://knowledge.digi.com/articles/Knowledge_Base_Article/XBee-ZigBee-Route-Discovery-and-Network-Address-Discovery" rel="nofollow noreferrer">here</a>. According to it the route with the lowest cost will be stored in a Routing Tables of the nodes.</p> <p>So far everything is fine, every node knows what to do, they can reach each other.</p> <hr> <p>Now, an intermediate node, between <strong>Node A</strong> and <strong>Node B</strong> breaks down, so the currently stored route becomes unusable.</p> <p><em>What happens in this case?</em> I imagine that when <strong>Node A</strong> wants to send a message, it will travel all the way to the broken link where it will get stuck. The last node in the route will send back a message about the failure which will trigger a new Route Discovery by <strong>Node A</strong>, then a new route will be found and everything will be alright again.</p> <p>It is generally fine (given I was correct); the network recovers. But I am wondering if there are any algorithms or methods that provide a network monitoring feature which continuously checks the state of the links presented in the Routing Tables. So <strong>Node A</strong> can be notified about the failure before it wants to send another message to <strong>Node Z</strong>, and instead of running into a dead end, it can start with a Route Discovery at once. So basically what I'm thinking of is a service which periodically checks the links.</p> <hr> <p>I understand that as ZigBee is usually used on battery powered, low-power devices such a mechanism would be not energy efficient.</p> <p>So in general what are now the most effective link failure detecting mechanisms that can be used in a low-power, wireless sensor network, especially in a ZigBee mesh network?</p>

2017-02-02T02:46:28.483

<h2>Option 1</h2> <p>One solution I have seen and I could recommend is to divide your warehouse in areas and create gateways for accessing to them with the forklift or trucks. Then you setup the antennas on those gateways and force the drives to pass through them in order to track the goods movement. Basically it is the same logic behind any shop store with those RFID antennas at the entrance scanning people going in and out, that triggers the alarm as soon as they read a tag that was not killed. The antennas should be powerful enough to scan a whole pallet or even a truck. Additionally you should also consider the type of RFID tag you will use.</p> <p>[Updated]</p> <h2>Option 2</h2> <p>Consider the case where the forklifts are the only that move the palets around the warehouse, why not setting the RFID antenna to them. Adding a geolocation sensor you can know exactly where the palet was stored and if you add a gyroscope you could even know the height of the rack. A step further could be to add a weight sensor to the forklift to detect when the palet is picked up and when is drop, plus the palet's weight to calculate the accumulated load of rack.</p>

|hardware|rfid|

IoT for industrial warehouse management

930

<p>Currently, I am using RFID technology for my warehouse management. My warehouse spans across 4 acres, I need to deploy so many RFID antennas and RFID readers to constantly scan the area for goods movement (active scanning). </p> <p>What technology is available to help me deploy multiple RFID antennas continuously?</p> <p>Currently, I am using an RFID antenna mounted on the wall and connected to the RFID reader. Every item is labelled with an RFID sticker. I've calculated that I will need 30 RFID antennas to cover the whole area. It also means each RFID antenna have to be assigned a unique identifier. Obviously this is not the practical way to do that. Are there any convenient way to achieve this?</p> <p><strong>Update 05-02-2017</strong></p> <p>Since I have some vehicle/manpower to move the item, another idea is to mount the RFID antenna and RFID reader to the forklift or provide RFID handheld to the manpower. But the downside is I have to stop the movement for maybe 1 day and quickly label each item and manually update the location. So future onwards when the vehicle mounted RFID equipments or RFID handheld will determine the location/movements of the goods. Is this the best way for current RFID technology? Seems like there are no better ways RFID can help in warehouse management.</p>

2017-02-02T10:14:15.523

<p>The ESP8266 was not designed with an Ethernet MAC, but this should not stop you. However, as Sean has said, it imposes a set of pretty severe restrictions on you. </p> <p>You say that you wish to stay with the ESP8266 platform, but if your project cannot deal with the measly data rates provided by using an ENC28J60-style chip, or bit-banging Ethernet, then there is an alternative. The <a href="https://espressif.com/en/products/hardware/esp32/resources" rel="noreferrer">ESP32</a> has a 10/100 Mb/s Ethernet MAC that only requires a PHY, magnetics, and an RJ45 connector, and the ESP32 modules are just as cheap (if not cheaper) than the ESP8266 ones. </p> <p>The unfortunate downside to this approach is that it does not appear that many ESP32 shields have made it to market yet.</p>

|ethernet|interfacing|power-sources|esp8266|

ESP8266 with ethernet connection

932

<p>I was wondering if someone knows a way to convert a ESP8266 to non-WiFi. I.e. have it connected through Ethernet, preferably with PoE possibility.</p> <p>Reason for asking: My plan is to have sensors in a locker which is not a wifi-friendly environment. I want to monitor humidity and temperature in particular. I have a lot of ESP8266 units and like the firmware ESPeasy, thus wanting to stick to that platform.</p>

2017-02-02T14:01:28.673

<p>According to OnStar - <a href="https://www.onstar.com/us/en/services/connections/4glte/setup_support.html" rel="noreferrer">Connecting to your vehicle's Wi-Fi Hotspot</a></p> <blockquote> <p>To get your hotspot name (SSID) and password, press the Voice Command button and say "Wi-Fi settings."</p> </blockquote>

|security|wifi|smart-cars|

Connect to Chevrolet Cruze Hot-Spot Wi-Fi

938

<p>The Chevrolet Cruze (2016) is supposed to have a Wi-Fi hot-spot. I do see it showing up in my available network connections, but how do I find the password? From my memory, the dealer didn't say what it was, and if they did, I don't remember what it was.</p> <p><strong>Is there a way to find my Chevrolet Cruze's Wi-Fi hotspot password on the car?</strong> (Obviously, I have physical access.)</p>

2017-02-02T20:29:47.640

<p>I use <a href="https://aeotec.com/products/aeotec-multi-sensor-6/" rel="nofollow noreferrer">Aeotec Multi Sensor 6</a>. It has sensors for</p> <ul> <li>humidity</li> <li>lux</li> <li>temperature</li> <li>movement</li> </ul> <p>It is not meant for outside, but I have two outside (front and back of house) under the eaves. They work fine. I make sure they both agree before declaring that its <strong>dark outside</strong>. I use this control outside lights and closing the blinds. As a bonus, when someone is outside at night, I turn teh lights on as well.</p> <p>I also use one in each room, to detect motion and lux to decide when to turn the lights on and off, in that room.</p> <p>Its a Z-wave compatible sensor and can run off a battery or a wired USB power. The latter is the main reason I use this device. Who wants to change batteries all the time.</p> <p>Finally, it does require a hub/server. But you can directly link the sensor to the light, which will bypass the hub.</p>

|smart-home|sensors|ifttt|connector-services|

Are there any IoT outdoor lighting sensors?

942

<p>I have been looking for an ambient light sensor to use with other IoT smart home devices. In my opinion this would be a commonly requested device for controlling internal lighting. For example if you had smart lighting, you may want to turn the lights off if the sun is shining brightly or turn the lights on if it's cloudy. Weather services could help, but ambient light at the location would be far more reliable.</p> <p>Bonus points for hubless design (i.e. Wi-Fi and not ZWave/ZigBee) and integration with IFTTT, etc is also key.</p>

2017-02-03T12:14:11.477

<p>As requested in comments, I am posting this as an answer. </p> <p>I recommend an <a href="http://www.orangepi.org/OrangePi2GIOT/" rel="nofollow noreferrer">Orange Pi 2G IoT</a>. They also have <a href="http://www.orangepi.org/Orange%20Pi%204G-IOT/" rel="nofollow noreferrer">a 4G model</a>.</p> <p>Here's the 2G version, which is considerably cheaper &amp; ought to be enough:</p> <p><a href="https://i.stack.imgur.com/q4pry.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/q4pry.jpg" alt="enter image description here"></a></p> <hr> <p>[Additional] I am very fond of the <a href="http://www.orangepi.org/" rel="nofollow noreferrer">Orange Pi</a> line, as it has long had things like a SATA controller, etc available and generally has a wider selection than the Raspberry Pi range.</p> <p>However, the <a href="https://onion.io/store/omega2p/" rel="nofollow noreferrer">Onion Omega 2</a>, is my favourite and, IMO, superior to any pi, but since it has no cellular capability is not the answer here; I just post this to help others). </p> <p>Two things that make it stand out are than it comes pre-load with Linux - in flash, and that, out of the box, it acts as a sever, so that it is straightforward to connect by WiFi. Check out the spec. There is also <a href="https://www.crowdsupply.com/onion/omega2-pro" rel="nofollow noreferrer">a new version</a> which is pricey at $49 but which has 8GB flash, as opposed to relying on micro SD card.</p> <p>The Omega 2 range is not much bigger than a large SIM card.</p> <p><a href="https://i.stack.imgur.com/R3YLH.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/R3YLH.png" alt="enter image description here"></a></p>

|mobile-data|

Embedded modem options

943

<p>I would like to embed a simple mobile modem in my laboratory device. The capability is not really important - I want to be able to send small amounts of data and have no hard requirements on transfer speed or latency. That means that slow data is OK, text message is OK and even manual modulation over a voice line is OK.</p> <p>Assume that I live in an area with generous availability to carriers. If you know of a modem that is applicable to only a part of the world, please give that as an answer with that information. If you know of a modem capable of operating anywhere, all the better. </p> <p>The capability of the modem is not really a concern as much as availability (to consumers), size and price, so GSM, 3G or LTE (even NMT!) matter a lot less than whether I can get my hands on one for a reasonable price and put it in a small shell. This means <em>I</em>, as an individual, want to buy typically <em>one</em> modem at a time.</p> <p>What brands, vendors and retailers can I choose from? Are there any caveats I should be aware of? </p>

2017-02-03T17:16:09.860

<p>Since no one is taking this one on, I'll take a shot at it. :) </p> <p><strong>Android Google Home App</strong>: <em>If</em> you have the Android Google Home app, <em>then</em> follow <a href="https://support.google.com/googlehome/answer/7071494" rel="nofollow noreferrer">these steps</a>:</p> <ol> <li><p>Make sure you're on the same wifi as your Google Home and open the Android app.</p></li> <li><p>Go to the hamburger menu, and go to <code>Help &amp; Feedback</code> > <code>Submit Feedback Report</code> (bottom of screen)</p></li> <li><p>Select the device you've had an issue with</p></li> <li><p>Select your correct e-mail address</p></li> <li><p>Write up your report! Include your e-mail address and relevant keywords.</p></li> <li><p>Check the "Include screenshot and logs" box.</p></li> <li><p>Submit!</p></li> </ol> <p><strong>Iphone &amp; Ipad</strong>: (I'll just quote from <a href="https://support.google.com/googlehome/answer/7071494" rel="nofollow noreferrer">the same Google Support page</a>):</p> <blockquote> <ul> <li>Make sure your mobile device or tablet is connected to the same Wi-Fi as your Google Home device.</li> <li>Open the Google Home app .</li> <li>In the top left corner of the Home screen, tap Menu and then Feedback.</li> <li>Tap the device you'd like to submit feedback for.</li> <li>In the feedback summary, write a brief description of your issue. Please include any important keywords.</li> <li>Be sure to check the boxes next to "Include system data" and "Include Google Account".</li> <li>Tap Preview in the bottom right corner to review your feedback. </li> <li>Tap Send in the bottom right corner to submit feedback.</li> </ul> </blockquote> <p><strong>But... there's more.</strong></p> <p>Of course, Google Home being what it is, you ought to be able to send feedback via voice, oughtn't you? The answer is yes. You should be able to... and you can! Simply say the following:</p> <pre><code>Ok, Google [or, Hey, Google] </code></pre> <p>then</p> <pre><code>Send Feedback. </code></pre> <p>And now you can fire away your bug or feedback report <em>by voice.</em></p>

|google-home|

How can I report an incorrect response from my Google Home?

945

<p>Sometimes, my Google Home gets a little confused and completely misinterprets what I've asked (and it seems other people get the same problem quite often).</p> <p>For example, the assistant <a href="https://www.reddit.com/r/googlehome/comments/5l3tyo/ok_google_play_everything_wrong_with_deadpool_in/" rel="noreferrer">thinks Home Alone is "everything wrong with Deadpool in 15 minutes or less"</a>, <a href="https://www.reddit.com/r/googlehome/comments/5ekt5o/sorry_something_went_wrong_when_youre_ready_give/" rel="noreferrer">just gives up sometimes when things go wrong</a> and <a href="https://www.reddit.com/r/googlehome/comments/5gvw22/calendar_is_wrong/" rel="noreferrer">can't read calendars correctly</a>.</p> <p>Obviously, when things go wrong, it'd be nice if the developers would fix the issue, so I'd like to know if it's possible to report a specific conversation as incorrect or broken, so that they can sort it out.</p> <p><strong>Is there any way I can alert the Google developers if I come across any bad behaviour, so that they can fix the issue?</strong> Is this even necessary at all?</p>

2017-02-04T14:47:13.990

<p>Remember, you are <strong>always</strong> processing data at the edge, even if it's not obvious. The choice to sample data at a particular frequency, whether that is 1Hz or 100Khz (particularly with analogue data), is a form of edge processing. Very few scenarios will transmit data at the maximum clock cycle of the processor.</p> <p>Some scenarios where explicit edge processing is useful</p> <ul> <li><strong>Bandwidth constraints</strong>. The often-quoted example is in the oil and gas industry where a lot of telemetry is gathered, and the bandwidth from the remote location is limited.</li> <li><strong>Low latency requirement</strong>. Especially in control systems where something needs to happen in response to data. When sub-second responses mean the difference between normal operation and failure, a second or two round-trip to the cloud is unacceptable.</li> <li><strong>Extremely low value of data</strong>. If nothing is likely to be gained from recording data, even in the future with sophisticated analytics, you might as well summarise and drop it at the edge. For example, mains power in the EU is expressed as 'nominally 230 V ±10% at 50Hz'. Given that you can handle that range, there is no point in transmitting the precise voltage every 100ms. If is better to transmit 'from this time to this time, the voltage was nominal'.</li> <li><strong>Ordering of events is important</strong>. Devices have a narrower scope and can perform some derivations easier than the cloud. One of these is where the derivation requires that the data is in order. For example, it is easy on a device when measuring, say voltage, when it enters the on or off state. Timestamping the voltage measurement and sending it to the cloud makes the derivation harder as data may come out of order, delayed or be completely lost.</li> <li><strong>As a failure mode</strong>. Connectivity to the cloud, or at least some of the processing, is likely to fail. All systems should be able to perform some edge-processing, even if it is dumbed-down, as a failure mode.</li> <li><strong>Non-IP mesh</strong> The cloud will only be accessible via a gateway for non-IP devices, such as those that communicate over a low-power network or CAN bus-type wired connection. It may be preferable for devices communicate directly with each other in a 'mesh', in which case IP connectivity isn't needed, never mind cloud connectivity. Mesh is the holy grail of edge computing, but difficult to do.</li> <li><strong>Privacy, trust, and regulatory issues</strong> Data can be collected that may be useful and valuable for analytics, but getting customer consent to collection and storage of the data may be difficult, and the cost and risk associated with managing access to the data may be too high. Facial recognition, and most image processing, is the obvious example. Another example is that all modern vehicles have GPS and connectivity built-in for emergency call response. Vehicle manufacturers and dealers could derive valuable insights from a stream of GPS data, but location data is personally identifiable in this scenario and shouldn't be collected, transmitted, processed and stored.</li> <li><strong>Security</strong> We are aware that IoT is currently suffering from security issues. While it is possible to create a secure environment with cloud-connected devices, security is a major issue that needs to be actively worked on. Highly secure gateways, edge-based threat detection and other as-yet unknown defense mechanisms are going to be necessary in most environments.</li> </ul> <p>When considering material about edge processing, remember to consider the source. Existing IT vendors that haven't cracked the cloud market (IBM, HP, Cisco) are worried that IoT, as the next big thing, bypasses them altogether. As a result they will aggressively market edge processing. Indeed, 'fog computing' is a term created by Cisco to have a 'cloud' closer to the ground (or something). Obviously cloud vendors are marketing the reverse, for their own bottom line.</p>

|edge-computing|cloud-computing|

Which problems with cloud computing make edge computing useful?

950

<p>I recently read an article in The Register, <a href="http://www.theregister.co.uk/2017/02/03/hpe_micro_data_centre_edge_computing_iot/" rel="noreferrer"><em>Don't let cloud slurp all your data. Chew it on the edge, says HPE</em></a>:</p> <blockquote> <p>The basic pitch is that HPE's gear can do compute on your shop floor without taking up large chunks of your floorspace, meaning you don't need to splash out on collecting and moving data back and forth, or spend megabucks on cloud services.</p> </blockquote> <p>However, edge computing (which essentially just seems like a buzzword for locally processing data!) seems to have a few problems with it to me. <a href="https://en.wikipedia.org/wiki/Cloud_computing#Limitations_and_disadvantages" rel="noreferrer">Wikipedia</a> quote a source which says, "Cloud computing is cheaper because of economics of scale", so surely edge computing misses out on the benefits you get from massive-scale computing in data centres?</p> <p><strong>Why would edge computing be useful in some cases?</strong> Is it only really useful in cases where <em>huge</em> amounts of data need to be sent, where it would be impractical to send it over the Internet?</p>

2017-02-04T20:49:22.473

<p>I managed to find my mistake. Mistakenly I assumed that the Client ID is a fix field but it is only part of the Payload of the message thus a <strong>length-prefix</strong> is needed. From the <a href="http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718028" rel="nofollow noreferrer">specifications</a>:</p> <blockquote> <p>The payload of the CONNECT Packet contains one or more length-prefixed fields, whose presence is determined by the flags in the variable header. These fields, if present, MUST appear in the order Client Identifier, Will Topic, Will Message, User Name, Password</p> </blockquote> <p>So one more byte should be decremented in the message. The correct steps:</p> <ol> <li>Deleting the last byte from the array, the 0x34.</li> <li>Decrementing the the Remaining Length field (2nd byte in the array) in the message. So from 32 to 31, 0x20 --> 0x1F.</li> <li><strong>Decrementing the length-prefix byte of the Client ID in the payload. In my case it is the 16th byte (counting from 1) <code>0x12</code> ---> <code>0x11</code>.</strong></li> <li>Decrementing the number of bytes parameter of the send function. From 34 to 33. (+2 because of the Header Flags and Remaining Length fields)</li> </ol> <p>After this additional step the broker sent back the CONNACK message.</p>

|mqtt|mosquitto|

How to modify only the Client ID in an MQTT CONNECT message?

955

<p>I am playing around with MQTT CONNECT messages. I have a simple C program which opens a TCP/IP socket towards an Mosquitto broker running on my laptop, sends an MQTT CONNECT message, (normally) receives the 4 byte long CONNACK reply then closes the socket and exits the program.</p> <p>Currently I do not build my own CONNECT message but use one from a Wireshark capture.</p> <p><a href="https://i.stack.imgur.com/ssrZa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ssrZa.png" alt="Wireshark Capture Screenshot"></a></p> <p>It can be exported as a C array, the MQTT part:</p> <pre class="lang-c prettyprint-override"><code>char packet_bytes[] = { 0x10, 0x20, 0x00, 0x06, 0x4d, 0x51, 0x49, 0x73, 0x64, 0x70, 0x03, 0x02, 0x00, 0x3c, 0x00, 0x12, 0x72, 0x6f, 0x6f, 0x74, 0x2e, 0x31, 0x34, 0x38, 0x35, 0x38, 0x39, 0x30, 0x38, 0x35, 0x37, 0x31, 0x39, 0x34 }; </code></pre> <p>Using this unmodified array everything works just fine, here is the broker's output:</p> <pre class="lang-bash prettyprint-override"><code>1486237905: New connection from 192.168.1.2 on port 1883. 1486237905: New client connected from 192.168.1.2 as root.1485890857194 (c1, k60). 1486237905: Sending CONNACK to root.1485890857194 (0, 0) 1486237905: Socket error on client root.1485890857194, disconnecting. </code></pre> <hr> <p>The problems start when I want to modify the Client ID in the message. My simplest attempt is chopping the last character <code>4</code> from the end of the ID.</p> <p>I think this requires three modifications in the actual code.</p> <ol> <li>Deleting the last byte from the array, the <code>0x34</code>.</li> <li>Decrementing the the <code>Remaining Length</code> field (2nd byte in the array) in the message. So from 32 to 31, <code>0x20</code> --> <code>0x1F</code>.</li> <li>Decrementing the number of bytes parameter of the <code>send</code> function. From 34 to 33. (+2 because of the <code>Header Flags</code> and <code>Remaining Length</code> fields)</li> </ol> <hr> <pre class="lang-c prettyprint-override"><code>char packet_bytes[] = { 0x10, 0x1F, 0x00, 0x06, 0x4d, 0x51, 0x49, 0x73, 0x64, 0x70, 0x03, 0x02, 0x00, 0x3c, 0x00, 0x12, 0x72, 0x6f, 0x6f, 0x74, 0x2e, 0x31, 0x34, 0x38, 0x35, 0x38, 0x39, 0x30, 0x38, 0x35, 0x37, 0x31, 0x39 }; if( send(s , packet_bytes , 33, 0) &lt; 0) { puts("Send failed"); return 1; } </code></pre> <p>It does not work, here is the broker's output:</p> <pre class="lang-bash prettyprint-override"><code>1486239491: New connection from 192.168.1.2 on port 1883. 1486239491: Socket error on client &lt;unknown&gt;, disconnecting. </code></pre> <hr> <p>I know that the <code>Remaining Length</code> field requires special enconding but not under 128.</p> <p><a href="https://i.stack.imgur.com/BMIus.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BMIus.png" alt="Remaining Length Table"></a></p> <p>What did I miss here, what should I modify beside the <code>Remaining Length</code> field?</p>

2017-02-05T11:36:21.817

<p>I found this a while back but I'm unable to attribute to the original author. Works great for existing logs, but can't 'tail -f' with this solution:</p> <p><code>sudo cat /var/log/mosquitto/mosquitto.log | grep -v datab|perl -pe 's/(\d+)/localtime($1)/e'</code></p> <p>Using this on linux, but should work on WSL/cygwin.</p>

|mqtt|mosquitto|microsoft-windows|

How to enable detailed logging of Mosquitto broker on Windows 7?

956

<p>I have a previous <a href="https://iot.stackexchange.com/q/955/14">question</a> and to get closer to a solution I want to enable Mosquitto broker logging on Windows 7.</p> <p>Originally I have started the broker manually as follows:</p> <pre class="lang-bash prettyprint-override"><code>mosquitto -p 1883 -v </code></pre> <p><code>-v</code> means verbose console logging. But this does not provide enough information, only the following line in case of my problem:</p> <pre class="lang-bash prettyprint-override"><code>1486293976: Socket error on client &lt;unknown&gt;, disconnecting. </code></pre> <hr /> <p>I have tried doing what is described in this <a href="https://stackoverflow.com/q/13986313/3820025">answer</a>. Here is the config file's logging part:</p> <pre class="lang-bash prettyprint-override"><code># Note that if the broker is running as a Windows service it will default to # &quot;log_dest none&quot; and neither stdout nor stderr logging is available. # Use &quot;log_dest none&quot; if you wish to disable logging. log_dest stdout # If using syslog logging (not on Windows), messages will be logged to the # &quot;daemon&quot; facility by default. Use the log_facility option to choose which of # local0 to local7 to log to instead. The option value should be an integer # value, e.g. &quot;log_facility 5&quot; to use local5. #log_facility # Types of messages to log. Use multiple log_type lines for logging # multiple types of messages. # Possible types are: debug, error, warning, notice, information, # none, subscribe, unsubscribe, websockets, all. # Note that debug type messages are for decoding the incoming/outgoing # network packets. They are not logged in &quot;topics&quot;. log_type error log_type warning log_type notice log_type information # Change the websockets logging level. This is a global option, it is not # possible to set per listener. This is an integer that is interpreted by # libwebsockets as a bit mask for its lws_log_levels enum. See the # libwebsockets documentation for more details. &quot;log_type websockets&quot; must also # be enabled. #websockets_log_level 0 # If set to true, client connection and disconnection messages will be included # in the log. connection_messages true # If set to true, add a timestamp value to each log message. log_timestamp true </code></pre> <p>In this case I have started the broker as follows:</p> <pre class="lang-bash prettyprint-override"><code>mosquitto -p 1883 </code></pre> <p><code>-v</code> option would override the config file with the default config so I have left that out. But I see no logging on the console.</p> <hr /> <p>Instead of <code>stdout</code> I have tried to log into a file, and changed the configuration as follows:</p> <pre class="lang-bash prettyprint-override"><code>log_dest file d:\mosquitto.txt </code></pre> <p>I have created the file manually and started the broker in the same way but no avail.</p> <hr /> <p>I do not get any log message if I do not use the <code>-v</code> option. How should it be done properly?</p>

2017-02-05T14:52:41.057

<p>Technically, different devices will communicate using protocols that are not internet-based, protocols that are proprietary, and tied together with different administration tools.</p> <p>The reality is, particularly in consumer IoT, that you are witnessing an important battle between vendors that have an interest in dominating the consumer IoT (or home automation) market. Vendors of chipsets will promote their chosen radio network, vendors of products will promote their management tools, and others will position themselves as the one hub to rule them all. People, and minnow tech companies, fed up with this try and promote standards, which often get co-opted by major players. You will see this where every 'standard' has an 'alliance' page, which is the source of their ability to produce a standard. </p> <p>There is no single 'hub', as there is no single vendor. People need to commit to an ecosystem (or two) and hope for the best. In much the same way that people will commit to the Apple or Android mobile ecosystem, they will commit to a 'smart home' ecosystem. Samsung wants to be the 'Apple of IoT', so does Philips, so do many others.</p> <p>While there are efforts to standardise, because of the frustrations that you are questioning, it is unlikely that any standard will emerge soon, and even more unlikely that it will be a truly open standard.</p> <p>This answer may seem cynical, and more opinion than fact, but IoT is a new market with huge rewards for vendors that dominate. Current users of IoT are early adopters that will be frustrated while the battle of technology giants is played out. Understanding the current state of the market is important to adjust your expectations while evaluating the technology. </p>

|smart-home|

Why do I need hubs for some devices when automating my home?

958

<p>When you get started with automating your home, you quickly find out that many devices need a hub or bridge to function correctly. For example, the Philips Hue bulbs need a <a href="http://www2.meethue.com/en-us/productdetail/philips-hue-bridge">bridge</a>, August Smart Locks need a <a href="http://august.com/products/august-connect/">different bridge</a>, and some people also buy hubs like the <a href="https://www.smartthings.com/uk/">SmartThings hub</a> or the <a href="http://getvera.com/">Vera hub</a>.</p> <p>There are <a href="https://www.reddit.com/r/homeautomation/comments/5cxmnl/do_i_need_a_smart_hub_to_go_with_my_echo/">lots</a> <a href="https://www.reddit.com/r/google_home/comments/5g03iu/do_i_need_a_smart_hub_of_some_sort_with_google/">of</a> <a href="https://www.reddit.com/r/amazonecho/comments/53ep6e/i_am_getting_a_dot_do_i_need_a_smartthings_hub_too/">people</a> who don't seem to be sure whether they need a hub when they start automating their home, but often the explanations aren't clear.</p> <p><strong>Why might I need a hub or bridge instead of just connecting all my devices straight to my home network?</strong></p> <p>For example, if I have some Philips Hue bulbs, an Amazon Echo and an <a href="https://www.ecobee.com/ecobee3/">ecobee3</a>, how can I figure out if I need a hub? Is there a methodology that will help me to determine which hub is best?</p>

2017-02-06T13:02:45.543

<blockquote> <p>Use only ASCII characters.</p> </blockquote> <p><a href="https://www.rfc-editor.org/rfc/rfc20" rel="nofollow noreferrer">ASCII format for Network Interchange</a> specifies that the ASCII range extends from hexadecimal 0 to 7F, i.e., 128 characters. I think % should be supported but not °.</p>

|mqtt|

Should I use special characters in MQTT topics?

966

<p>I have used MQTT to connect all my ESP8266 units but I have a general question regarding topics. According to <a href="http://www.hivemq.com/blog/mqtt-essentials-part-5-mqtt-topics-best-practices" rel="noreferrer">www.hivemq.com</a>:</p> <ul> <li>"Leading forward slash" <code>/</code> should be avoided.</li> <li>Spaces should be avoided.</li> <li>Use only ASCII characters.</li> <li>Embed a unique identifier or the ClientId into the topic.</li> <li>Etc.</li> </ul> <p>I have pretty much applied to this but I use some special characters (% and ° for example). For example I use:</p> <p><code>Garage_Sensor_001/Temperature/°C</code> <code>value</code></p> <p><code>Livingroom_HID_002/Switch_001/Action</code> <code>value</code></p> <p><code>Bedroom_Sensor_001/Motion_001/Detection</code> <code>value</code></p> <p>I.e.</p> <p><code>PLACEMENT_OF_NODE/TYPE_OF_SENSOR_UNIT_OR_ACTION/FUNDAMENTAL_UNIT_OF_VALUE_IF_ANY</code></p> <p>So my question is: <strong>Should I use special characters when naming MQTT topics?</strong></p>

2017-02-06T23:44:25.123

<p>The problem was bad contacting between SIM card contact block and the board. The problem was difficult to find because when I touched the terminal for measurement it makes pressure to the board, the contact happens and the problem couldn't be observed.</p> <p>I made a check list for resolution:</p> <ul> <li>Is SIM card working?</li> <li>Are voltages on card correct?</li> <li>Can bus signals be seen in a scope?</li> <li>Is SIM card contacts block footprint correct?</li> <li>Is card in the correct position?</li> <li>Are SIM card VDD and GND both connected?</li> </ul> <p>After eliminated most of all those questions the only possibility was the last one. Fact! I touched GND in the card holder very very delicately and the problem was there, a Heisenbug.</p> <p>I hope this answer and checklist help a lot, because information about this kind of problem is very difficult to find.</p>

|hardware|mobile-data|gsm|

Receiving "ERROR" message from SIM800C module

970

<p>Most of the commands I send to <a href="https://www.elecrow.com/download/SIM800C_Hardware_Design_V1.02.pdf" rel="noreferrer">SIM800C</a> module returns <code>ERROR</code> message to me.</p> <p><em>For example:</em></p> <p>If I sent <code>AT+CSQ</code>, it returns an expected response.</p> <p>One of the basics commands that doesn't worked for me is the <code>AT+CPIN?</code> PIN checking command.</p> <p>In the datasheet, I don't even can find the possible cause for this error.</p> <p><em>Another information I have:</em></p> <p>Among many explanations for the problem, I found one, and I don't remember which was, that said to send a command to expand <code>ERROR</code> in details. As result from <code>AT+CPIN?</code>, I received a error that corresponds to "no card inserted" and I don't know why. The SIM card works fine, I have tested on my phone.</p> <p>The SIM card is not detected by module. I measured the voltage in the card bus and I have 0 volts. I don't know it is the cause or the consequence for bad functioning, not even it is related to this main problem of this question.</p> <p><em>This is my circuit:</em></p> <p><a href="https://i.stack.imgur.com/OeOhC.png" rel="noreferrer"><img src="https://i.stack.imgur.com/OeOhC.png" alt="SIM800 circuit sheet"></a></p>

2017-02-07T17:18:34.337

<p>It looks like probably not. I have searched around quite a bit, and I have found a couple pieces of evidence:</p> <h3>1. The article you referenced.</h3> <p>If you read the article again, you will see that the Google Home did pick up the signal - and interpreted it as a wake up call. Probably the volume and other background noise prevented the signal from being understood, hence, the &quot;Sorry, something went wrong.&quot;</p> <h3>2. Google Assistant has retired Personalized Voice Recognition.</h3> <p>It appears that 2015, Personalized Voice Recognition <a href="https://www.quora.com/Why-was-Google-Nows-Personalized-voice-recognition-retired-Personalized-Voice-Recognition-setting-is-retired" rel="nofollow noreferrer">has been retired</a>. This means that Google is basing their recognition off of a larger database of various different accents and dialects, not off of a personalized recognition of your voice in particular. There is no reason why the voice of the guy on TV should be any different.</p> <hr /> <p>So as far as I can tell, the answer is,</p> <h3>No, for the moment, Google Home can be triggered by advertisements.</h3>

|google-home|

Does the Google Home have any protection against TV advertisements triggering it?

980

<p>Apparently, <a href="http://www.theverge.com/2017/2/5/14517314/google-home-super-bowl-ad-2017?utm_campaign=theverge&amp;utm_content=chorus&amp;utm_medium=social&amp;utm_source=twitter" rel="noreferrer">lots of Google Home speakers were activated by Google's Super Bowl ad</a>:</p> <blockquote> <p>Early during tonight’s game, Google’s ad for the Google Home aired on millions of TVs. We’ve actually seen the ad before: loving families at home meeting, hugging, and being welcomed by the Google Assistant. Someone says “OK Google,” and those familiar, colorful lights pop up.</p> <p>But then my Google Home perked up, confused. “Sorry,” it said. “Something went wrong.” I laughed, because that wasn’t supposed to happen. I wasn’t the only one.</p> </blockquote> <p>I recently asked about <a href="https://iot.stackexchange.com/questions/695/how-can-i-stop-alexa-from-ordering-things-if-it-hears-a-voice-on-tv">how you can stop Alexa from being activated by TV presenters</a> and <a href="https://iot.stackexchange.com/questions/828/why-doesnt-the-amazon-echo-respond-to-advertisements-or-reports-about-alexa">why Amazon Echos <strong>don't</strong> respond to TV ads</a>, but this article makes me wonder if Google thought to add the same sort of protections (I suspect the answer is no, but couldn't find any sources to prove it).</p> <p><strong>Does the Google Home use any sort of frequency detection or signalling to stop advertisements from triggering the device?</strong></p>

2017-02-08T03:50:01.500

<p>Although it's not ideal, you could use two IFTTT recipes to allow you to call your phone: one to set the ringtone volume to maximum, and one to actually call the phone. It's a little more involved than I'd like, but since IFTTT offers no chaining of actions, it's the best you'll get.</p> <p><strong>Recipe 1</strong>: <strong>If</strong> <a href="https://ifttt.com/amazon_alexa" rel="nofollow noreferrer">Amazon Alexa > Say a specific phrase</a> <strong>Then</strong> <a href="https://ifttt.com/android_device" rel="nofollow noreferrer">Android Device > Set ringtone volume</a>.</p> <p>You could set the specific phrase to "set my phone volume to maximum", so you simply have to announce "Alexa, set my phone volume to maximum" when you want to do that. Of course, for the Google Home, replace the Alexa trigger with the Google Home trigger.</p> <p><strong>Recipe 2</strong>: <strong>If</strong> <a href="https://ifttt.com/amazon_alexa" rel="nofollow noreferrer">Amazon Alexa > Say a specific phrase</a> <strong>Then</strong> <a href="https://ifttt.com/phone_call" rel="nofollow noreferrer">Phone Call > Call my phone</a>.</p> <p>As you'd expect, this will call your phone, hopefully making quite a loud noise now the volume is set to maximum. IFTTT only support US phone numbers at the minute though; if you're in another country, you may have to use a different method (maybe a notification or email).</p>

|alexa|amazon-echo|google-assistant|

Alexa or Google Assistant "Find My Phone" integration with Android Device Manager?

984

<p>Is there a solution for supporting "find my phone" from either Amazon Alexa or Google Assistant, using the native Android Device Manager? Or does Google even provide a web services API that could be used to develop this?</p> <p>My Google Home does not (yet) support this, which is a bit surprising, given the integrated Google ecosystem: "Sorry, locate device is not yet supported."</p> <p>Alexa depends upon a 3rd-party integration, with TrackR and IFTTT seeming to be the most popular ones. TrackR requires an additional app - and initial experience shows it to be a battery hog. The only IFTTT applets I've found rely on calling the phone, which won't help much if it is on silent.</p> <p>Using the native <a href="https://support.google.com/accounts/answer/6160491?hl=en">Android Device Manager support</a> would seem to be the most ideal here - as it wouldn't require any additional software, and can ring the device even if it's set to silent or vibrate.</p>

2017-02-08T17:29:35.180

<p>You do not want a WiFi antenna on your PCB. If you take this approach, you will need to do some RF layout and submit for type-approval/FCC testing. The beat approach to this sort of problem is to use a WiFi module. Here is a page discussing the <a href="http://hackaday.com/2016/07/28/new-chip-alert-rtl8710-a-cheaper-esp8266-competitor/" rel="nofollow noreferrer">esp8266 and RTL8710</a> modules to give you an idea of what is out there. </p> <p>These modules are (probably) designed so you can use them without having to repeat any regulatory testing. The on-board MCU has a small amount of excess processing power (above what is required to manage the wireless communication) and you can use this to interface to your sensors.</p> <p>If your sensor is analogue, you will need some sort of ADC. Otherwise, find a sensor with an SPI (or similar) digital interface. Your PCB <em>will</em> need to handle connector issues, power supply, indicators and display, that sort of thing.</p>

|hardware|wifi|

How can I design a simple Internet-connected controller for a sensor/heater?

988

<p>I am in the process of creating a simple and cheap Wi-Fi PCB design that can send and receive messages to an app (through a cloud of course). I intend to attach this PCB to a fish tank temperature gauge and a fish tank heating tube.</p> <p>Basically here are the only forms of communication between the PCB and my app: </p> <ol> <li><p>Send temperature readings when requested by app user</p></li> <li><p>Receives requests to change temperature high or lower</p></li> <li><p>Turn heating device on/off</p></li> <li><p>I need to configure the PCB so that it can communicate with a cloud service (installing SDKs, frameworks, and program logic to handle sending/received messages through cloud) </p></li> </ol> <p>What components do I need in my PCB that allows me to achieve these tasks? And what is the bare minimum flash and processing that can handle those tasks, or do I not even need processor chip or flash memory? I'm a beginner with PCBs.</p>

2017-02-08T18:43:24.330

<p>This page describes the <a href="http://developers.chirp.io/docs/chirp-technology-overview" rel="nofollow noreferrer">chirp protocol</a>:</p> <blockquote> <p>An entire chirp is a sequence of 20 pure tones of 87.2ms each. The first 2 tones are a common ‘front door’ pair – "hj" – to indicate to a device that the following tones are a chirp shortcode; the next 10 tones represent the 10-character payload. The final 8 tones are Reed-Solomon error correction characters.</p> </blockquote> <p>This doesn't describe the error rejection process, but it is likely to be similar to the way that <a href="https://en.m.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling" rel="nofollow noreferrer">DTMF</a> protocols rely on a consistent band-pass channel. Each tone needs to fit in a time window, with amplitude and frequency constraints. Making each tone relatively long allows some improvement in the signal/noise ratio, DSP is capable of matching a audio stream against all possible legal tone sequences to recognise a potential signal within the noise, and there is a good dose of error correction coding too.</p>

|protocols|

How can Chirp transmit data over sound without getting interference?

990

<p>I was recently reading about <a href="https://www.chirp.io/" rel="noreferrer">Chirp</a>, a data-over-audio protocol that sends information through (rather literally) chirping sounds either in audible or ultrasound frequencies.</p> <p>One of the use cases suggested on the website is for transmitting game data between devices, and The Register <a href="https://www.theregister.co.uk/2017/01/24/chirp_nuclear_power_station_iot_audio_sensors/" rel="noreferrer">have an article on Chirp being used in nuclear power stations</a> because RF transmissions (e.g. Wi-Fi) are not allowed due to the risk of interference:</p> <blockquote> <p>As for the nuclear power stations, Chirp's tech has found a useful niche in IoT sensor applications where traditional RF networking cannot be used. Nuclear power stations have an absolute ban on RF over fears of interference – thereby ruling out Wi-Fi, Bluetooth and all the usual go-to wireless networking technologies – and when EDF wanted to monitor equipment in its turbine halls the usual shielded cable was seen as too costly and bulky.</p> <p>&quot;They've got machine plant they want to monitor, diagnose and talk to,&quot; said Nesfield. &quot;Chirp is being used in those contexts because it's not RF and doesn't interfere.&quot;</p> </blockquote> <p>In a lot of the cases they've suggested, I imagine there must be quite a lot of noise which could interfere with the chirps - <strong>how does Chirp stop other sounds from interfering with the data that they want to send?</strong></p>

2017-02-09T10:27:14.883

<p>If you only want control inside the home sure it is possible.</p> <p>The problem is if you want to offer control from outside the home things get difficult. Neither the client or the server are likely to have a static IP, there are likely to be firewalls and/or NATs in the way.</p> <p>It is possible for the user to set up port forwarding/exceptions in their router/firewall and set up some kind of dynamic DNS to track their dynamic IP and point their client at the dynamic DNS entry but it takes a technical user to do it and it creates security issues.</p> <p>Having a server in a known location on the public Internet is the easiest way to make sure your things can communicate with each other regardless of dynamic IPs, NATS, egress only firewalls etc. There are still some security issues but they are reduced as you can enforce security policies on the server which you can more easily monitor and update.</p> <p>Ipv6 loses the NAT but dynamic IPs and egress only firewalls are still likely to be common.</p>

|wifi|system-architecture|

Is it possible to commercially sell a Wi-Fi IoT product that DOESN'T use cloud?

993

<p>If I wanted to use my phone to control a simple Wi-Fi connected device that just turns the light on or off, or a simple temperature gauge, why don't I just communicate directly with the device instead of going through a cloud? No data persistence or heavy processing or any other fancy stuff to deal with. </p> <p>Is there anything stopping me from designing such a simple IoT product and just start mass producing it and selling it? Seems cheaper to cut out the middle man and not have to deal with a cloud's cost/message fees.</p>

2017-02-10T14:24:22.947

<p>I list microcontrollers up to 30 EUR here. I'll keep looking and update this if I find something interesting. A really good solution would be something below 10 EUR, but I haven't found anything like that.</p> <ul> <li>The <a href="https://www.ebay.de/itm/LANTRONIX-XP1001000-05R-XPort/123815535100" rel="nofollow noreferrer">Lantronix XPort is 30 EUR</a> + shipping, in theory that would work too, but the prices are interesting, they are between 20 and 200 EUR, so hard to tell which one is the real price.</li> <li>The <a href="https://www.amazon.de/s?k=orange%20pi%20zero&amp;language=en_GB" rel="nofollow noreferrer">Orange PI Zero is 28 EUR</a> + shipping, I don't know from where the other answerer got that 7 USD price. In Europe that is very far from the truth. I don't think you can buy it in the US that cheap either.</li> <li>The <a href="https://www.olimex.com/Products/IoT/ESP32/ESP32-POE-ISO/open-source-hardware" rel="nofollow noreferrer">Olimex ESP32-POE-ISO is 25 EUR</a> + shipping. There is a <a href="https://www.olimex.com/Products/IoT/ESP32/ESP32-POE/open-source-hardware" rel="nofollow noreferrer">cheaper version for 18 EUR</a>, but it is not galvano isolated, so it is easy to fry.</li> <li>The <a href="https://www.komputer.de/zen/index.php?main_page=product_info&amp;cPath=38_21&amp;products_id=175" rel="nofollow noreferrer">Itead IBoard is for 20 EUR</a> + shipping currently, but it is relative rare.</li> <li>The <a href="https://www.berrybase.de/raspberry-pi-zero-w" rel="nofollow noreferrer">PI Zero W + POE splitter is 16 EUR</a> + shipping total at least. The active POE micro USB splitter is 6 EUR at least, which is relative expensive. The PI Zero W is currently 10 EUR.</li> <li>The <a href="https://www.banggood.com/Geekcreit-30-Pin-ESP32-Development-Board-WiFibluetooth-Ultra-Low-Power-Consumption-Dual-Cores-ESP-32-ESP-32S-Board-p-1461896.html?rmmds=search&amp;cur_warehouse=CN" rel="nofollow noreferrer">ESP32 is 5 EUR</a>, but it does not have POE or even RJ45 normally. It is possible to <a href="https://hackaday.com/2017/04/18/enabling-ethernet-on-the-esp32/" rel="nofollow noreferrer">add POE the DIY way</a>, so with a little luck you might end up with the ESP32-POE-ISO if you have the right skills. I don't.</li> </ul>

|hardware|microcontrollers|ethernet|

Cheap IoT microcontroller with PoE

1005

<p>Can anyone recommend a simple micro-controller with some I/O (&lt;8) that can be powered using PoE, something cheap like Raspberri Pi Zero. The requirements are:</p> <ul> <li>Support PoE integrated. No power battery maintenance.</li> <li>Support TCP/UDP communication</li> <li>few I/O.</li> </ul> <p>The thing is that if I need a power adapter per each micro controller distributed around the house I will require a lot of budget. Having a set if chips with PoE I avoid occupying the power outlets and I have safe communication at the same time.</p> <p>Basically what I want is to through some Ethernet cables and add some sensors and actuator without having to set up a full Arduino in each end-point. And not having to change the battery every year. And also I don't want to spend extra money buying adfruits and shields.</p> <p>Another alternative that fulfill somehow my requirements, although it is not what I was thinking of, it is to install a commercial Wi-Fi power outlet. I find it bit expensive for the amount of units I need.</p> <p>Here is one <a href="http://rads.stackoverflow.com/amzn/click/B00KT50HK4" rel="noreferrer">example</a> from Amazon.</p> <ul> <li>This solves my power requirements by taking the power directly from the power net.</li> <li>Provides communication over Wi-Fi.</li> <li>I can connect any microcontroller with a power adapter to it.</li> <li>Since it is commercial Hardware I believe that it will provide some safety level of operation, in comparison to a testing board I could do on my own, I won't like to set the kitchen on file because a silly short cut.</li> </ul> <p>Of course, the fun will be to develop the application by myself</p> <p><a href="https://i.stack.imgur.com/3xIQs.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/3xIQs.jpg" alt="Orvibo Socket"></a></p>

2017-02-10T16:01:06.320

<p>You mention “certificates”, but from context, I think you're referring to two different things.</p> <ul> <li><p>Your device has a <em>private</em> key, which is unique to this device and not known outside the device. This key identifies your device. Anybody who can access that key can impersonate the device. That means that they can, in particular:</p> <ul> <li>Publish valid, but incorrect data on the channels that your device is legitimately authorized to publish to.</li> <li>Publish invalid data that will get the legitimate device banned.</li> <li>Possibly, depending on the use case, expose some private information of the owner of the device.</li> </ul> <p>This private key had better remain confidential.</p></li> <li><p>Your device probably has at least one <em>public</em> key, which allow it to recognize which servers it's talking to. It's ok if anybody can read this key: it's public. But an attacker should not be able to modify the key. Otherwise, they could communicate with the device and impersonate the server. This could allow them to do things like:</p> <ul> <li>Push a firmware update to the device.</li> <li>Push a configuration update to the device.</li> <li>Make the device upload its data to a different location.</li> </ul></li> </ul> <p>The good news is that this threat analysis is actually not very relevant. <strong>You do not need to sacrifice any security</strong>! (At least not confidentiality and authenticity properties — if you store stuff externally, then availability takes a hit, because that's one piece of the system that could go missing.)</p> <p>As long as you have at least 128 bits of storage that you can write to at least once, which you have and more, you can implement a secure remote storage solution. Use the limited-space on-device storage to store a secret key. This secret key must be unique per device; the STM32 has a hardware RNG, so you can generate it on the device during first boot. If your device didn't have a hardware RNG, you could generate the key in a secure off-device location and inject it onto the device.</p> <p>With this key, use <strong><a href="https://en.wikipedia.org/wiki/Authenticated_encryption" rel="noreferrer">authenticated encryption</a></strong> for things that you store off the device. When you want to read some data from external storage, load it, decrypt-and-verify it. When you want to write some data to external storage, encrypt-and-sign it. This guarantees that the data is as confidential and authentic as the data in the internal storage.</p> <p>Authenticated encryption is enough to guarantee the confidentiality and <em>authenticity</em> of the data, but it doesn't quite guarantee its <em>integrity</em>.</p> <ul> <li>If there's more than one chunk of data, then when the device reads back a chunk of data, it can't be sure that this is the correct chunk. Solution: include a unique identifier in the content of each chunk (e.g. start each chunk with one of <code>"AWS-IoT private key."</code>, <code>"configuration CA certificate."</code>, <code>"publishing server CA certificate."</code>, <code>"user personal data."</code>, …).</li> <li>If you update the data at some point, then when you read it back, you can't be sure that you're getting the latest version of that data. If someone can modify the external storage, they can't put fake data because that would fail the authenticity check, but they can restore old data, because what used to be authentic is still authentic. Solution: in each data chunk that is stored externally, include a counter which you increment each time you write a new version of that chunk. When you read a chunk back, verify that it's the expected version.</li> </ul> <p>To avoid bricking a device in case the external storage is damaged or otherwise lost, in the limited space you have space on internal storage, you should give priority to whatever is needed to reset the device to a “good” state, e.g. a factory reset. The second priority will be performance considerations.</p>

|security|mqtt|aws-iot|

Is it a bad practice to keep certificates on external memory?

1006

<p>We're working on AWS-IoT using an STM32 microcontroller. </p> <p>Till today, we were writing the certificates to the flash and locking the flash from external reading. As the application code increases, we're getting lesser space on the flash so we were planning to move the certificate externally on an SD card / EEPROM and read whenever it was needed before connecting to AWS-IoT. </p> <p>Notes:</p> <ul> <li><p>The policy written for the thing will allow only devices with particular names to connect on that particular certificate.</p></li> <li><p>The thing is allowed to publish to only 2 channels (it's name and a data feed channel) which is connected to a data processor which will ignore any rogue packets coming to it.</p></li> <li>If the thing publishes/subscribes to any other topic, AWS will disconnect the thing immediately. </li> </ul> <p>If I detect a device is stolen/rogue we deactivate the key from the server.</p> <p>What can an exploiter do with the certificates (RootCA, server key, client key)?</p> <p>Is it a bad practice to keep certificates for such usecase on an external storage which can be accessed by an exploiter? </p>

2017-02-10T18:22:27.323

<p>Do you need to? You can implement a cryptographically secure random generator if you have two things: some rewritable secure storage, and an initial seed. That is, it's enough to seed the RNG once, and then save its state and work off the saved state. It isn't ideal, it would be better to mix in entropy periodically, but it's ok, especially for a development protoype.</p> <p>You do need to have rewritable secure storage. If the device only has ROM and non-secure storage, then this approach is not possible. There must be a location where you can store the RNG state in such a way that your adversaries can neither read it nor modify it.</p> <p>The way this works is, when the device boots, it loads the current RNG state, and uses it to generate some enough random bytes for twice the size of the RNG state. Write the first half as the new saved RNG state, and use the second half as the initial RNG state for the current session. With any cryptographically secure PRNG, this yields a cryptographically secure PRNG. Note that it's critical that you don't reuse a stored RNG state, that's why you must write a new independent RNG state before you start using the RNG.</p> <p>The initial entropy injection can happen during manufacturing, or when the device is set up. Usually those things happen with a connection to a PC which can generate the entropy on behalf of the device.</p>

|security|hardware|

Can I implement a (weak) entropy source in FPGA?

1010

<p>I'm working with an IoT platform in FPGA for evaluation and prototyping. I need to provide support for TLS, and for that I need an entropy source.</p> <p>I understand that true random noise sources are quite specialist (if even practical) in FPGA, since the device performance is often pretty good (and hard to find any corner-case parameters), but I can implement a pseudo-random sequence generator without any problems.</p> <p>I only have some standard I/O channels (uart, I2C, etc), nothing that looks like it can provide even much to seed a PRBS - except maybe an audio ADC input. Are there maybe any reliable tricks for generating entropy in an FPGA which I ought to consider?</p> <p>Assuming that I use a PRBS, I can potentially attach an external noise source which I could certainly use as a seed. I'm interested to know how much this would actually add to my TLS implementation. Would this be reliable and secure, or only slightly better than using a fixed pseudo-random sequence? Would I need to keep polling the external noise source for more entropy?</p> <p>It's OK if the entropy source I end up with isn't properly crypto-secure (since this is just for prototyping), but I'd like to understand the cost-quality trade-off.</p>

2017-02-11T20:06:19.907

<p>Alexa supports <a href="https://developer.amazon.com/public/solutions/alexa/alexa-skills-kit/docs/speech-synthesis-markup-language-ssml-reference" rel="nofollow noreferrer">SSML</a>, which is an XML-like markup language for speech. Instead of returning plain text from your service, you can use SSML responses. The <code>&lt;phoneme&gt;</code> tag is what you need in particular:</p> <blockquote> <h2>phoneme</h2> <p>Provides a phonemic/phonetic pronunciation for the contained text. For example, people may pronounce words like “pecan” differently.</p> </blockquote> <p>For English words (especially US English), Alexa should be able to pronounce any word if you give it the correct phonetic pronunciation:</p> <blockquote> <p>The following tables list the supported symbols for use with the phoneme tag. These symbols provide full coverage for the sounds of US English. Note that many non-English languages require the use of symbols not included in this list, which are not supported. Using symbols not included in this list is discouraged, as it may result in suboptimal speech synthesis.</p> </blockquote> <p>^{Quotes from <a href="https://developer.amazon.com/public/solutions/alexa/alexa-skills-kit/docs/speech-synthesis-markup-language-ssml-reference#phoneme" rel="nofollow noreferrer">Amazon documentation</a> on SSML.}</p> <p>Here's an example of giving Alexa a specific pronunciation:</p> <pre><code>&lt;speak&gt; &lt;phoneme alphabet=&quot;ipa&quot; ph=&quot;hɛˈləʊ̯&quot;&gt;Hello&lt;/phoneme&gt;. &lt;phoneme alphabet=&quot;ipa&quot; ph=&quot;bɔ̃.ˈʒuʁ&quot;&gt;Bonjour&lt;/phoneme&gt;. &lt;/speak&gt; </code></pre> <p>The <code>&lt;phoneme&gt;</code> tag supports the <a href="https://en.wikipedia.org/wiki/International_Phonetic_Alphabet" rel="nofollow noreferrer">IPA</a> and <a href="https://en.wikipedia.org/wiki/X-SAMPA" rel="nofollow noreferrer">X-SAMPA</a> phonetic alphabets. You can typically find IPA spellings for any word on <a href="https://en.wiktionary.org/wiki/hello#English" rel="nofollow noreferrer">Wiktionary</a> or through Google.</p> <p>For longer messages, it may be best to use the <code>&lt;audio&gt;</code> tag and record a custom voice:</p> <blockquote> <p>The audio tag lets you provide the URL for an MP3 file that the Alexa service can play while rendering a response. You can use this to embed short, pre-recorded audio within your service’s response. For example, you could include sound effects alongside your text-to-speech responses, or provide responses using a voice associated with your brand.</p> </blockquote> <p>^{Quoted from Amazon documentation on <a href="https://developer.amazon.com/public/solutions/alexa/alexa-skills-kit/docs/speech-synthesis-markup-language-ssml-reference#audio" rel="nofollow noreferrer"><code>&lt;audio&gt;</code></a>.}</p>

|alexa|

How can I change Alexa's pronunciation of a specific word in a skill?

1016

<p>Sometimes, when developing an Alexa skill and programming the responses from my service, Alexa mispronounces one of the words in my reply, confusing the user.</p> <p>For example, if I wanted Alexa to say a word in a different language (perhaps for a language learning skill), <strong>how can I tell Alexa how to pronounce the word correctly, rather than apply English pronunciation rules?</strong></p> <p>This also applies to English words with odd pronunciations; is there a way to dictate to Alexa the correct pronunciation, or replace it with a custom sound that is correct? Do I need to use additional markup or an API call?</p>

2017-02-13T13:42:30.517

<p>From the context, I believe it is referring to interconnectivity <strong>with other alarms in the house</strong>. From earlier in the article:</p> <blockquote> <p>Most important, an alarm should connect wirelessly with other alarms in the home, or come in a hardwired version that you can wire to other alarms, so that when one alarm senses danger all alarms in the house will sound. This is a crucial safety feature that can save you precious seconds in evacuating your home. Also, many states now require interconnected alarms for new construction, so if you do a significant remodel in your home, you don’t want to end up having to buy a different brand of alarm for the new area (most brands don’t play well with one another when it comes to interconnected alerts).</p> </blockquote> <p>The author of that article seems to use <em>interconnected</em> to refer to the alarms connecting together so that they all sound together in case of a fire. The Roost Smart Battery does not do this, because it just works by listening to detect your alarm going off with a piezoelectric sensor, <a href="http://www.techhive.com/article/3004024/home-tech/roost-smart-battery-review-this-is-the-best-smoke-alarm-battery-you-can-buy.html" rel="nofollow noreferrer">according to TechHive</a>:</p> <blockquote> <p>The detector relies on the high-pitched sound of the alarm to deform a piezo-electric sensor to trigger its own alarm. I intentionally installed the battery in the smoke detector in my master bedroom because its siren is defective—it makes more of a growl than a high-pitched squeal. But the Roost still went into an alarm state, perhaps after picking up the noise of the detector in the hallway.</p> </blockquote> <p>Your smoke alarm is still 'dumb' and can't share its state with other alarms, and the smart battery has no way of causing your alarm to trigger, either.</p> <p>The <a href="http://getroost.com/index" rel="nofollow noreferrer">Roost Smart Battery</a> is <strong>definitely</strong> connecting wirelessly with your phone, though. The title of their website is <em>"Roost Wi-Fi battery for smoke and CO alarms"</em>, so it's plainly obvious that the device does connect via Wi-Fi to your phone.</p>

|smart-home|roost|

How does the Roost Smart Battery connect?

1022

<p>I've been reading about the Roost Smart Battery. Essentially, it's a battery you can install in your smoke detector which is supposed to notify you on your phone if your smoke detector goes off. It also gives you the capability of silencing your smoke detector from your phone.</p> <p>According to <a href="http://thewirecutter.com/reviews/best-smart-smoke-alarm/" rel="noreferrer">The Wire Cutter</a>:</p> <blockquote> <p>...Roost will automatically notify someone else about the alarm in your home when it’s triggered, without giving that person control over all your other smart-home devices (as is the case with Nest’s version of this feature). But unlike the [Nest] Protect, the Smart Battery doesn’t give you voice alerts, wireless interconnectivity, integrations with smart-home devices, or self-testing sensors [...]</p> </blockquote> <p>According to my understand (maybe flawed) of the word interconnectivity, it means something along the lines of this definition from Wikipedia:</p> <blockquote> <p>Interconnectivity refers to the state or quality of being connected together, or to the potential to connect in an easy and effective way</p> </blockquote> <p>If the Smart Battery is not in the state of being connected together with your phone, how would they communicate? There is obviously a flawed premise. I assume the flawed premise is my definition of the term interconnectivity. What do they mean by saying that the Roost Smart Battery does not give wireless interconnectivity?</p>

2017-02-13T17:21:19.743

<p>I think you will find modules without too much trouble, there have been chips around for over a year that I found (and there is a module on Kickstarter which looks like a simple small production run sales testing exercise).</p> <p>A 6LoWPAN to 3G gateway is probably a bit of an esoteric use case - any you can find will be built-in to an end product, so it might be cheaper to assemble a unit from modules (or re-purpose an old phone maybe depending on the scenario).</p> <p>Just to elaborate on the 'how' part, it seems to be common now for these radio interfaces to be integrated with a reasonably powerful MCU which handles the communication stack. Not just the link-layer, but some of the security aspects of the protocol too. So this would easily be able to interface to a GSM module through a UART, without needing a further processing device. Building the radio stand-alone would actually be harder than having it tightly integrated with a control processor. You should also be wary of trying to use the asic directly on your own board - using a module removes the challenge of RF layout and type approval.</p>

|6lowpan|

Are there any 6LoWPAN to 3G gateways available on the market?

1024

<p>I'm looking for a gateway to pass from a 6LoWPAN over 802.15.4 network to 3G. Are there any on the market, or do I have to build one for myself based on Arduino or Raspberry Pi?</p>

2017-02-14T19:28:34.000

<p>A slightly obscure answer is 'from the sensor'. By making the hardware event driven you can potentially improve the standby power by such a large magnitude that a battery can be regarded as a non-replaceable part of your hardware.</p> <p>See <a href="http://www.bristol.ac.uk/engineering/research/em/research/zero-standby-power/" rel="nofollow noreferrer">this research</a> from the University of Bristol where they have optimised a switching element for pA leakage. Although I've seen this in passing before, I didn't appreciate the practical value till watching a video which described the scope for using the device.</p>

|smart-home|sensors|power-consumption|sustainability|

Where can I harvest energy in my home to power my wireless sensors?

1040

<p>I was reading this article, <a href="http://www.batterypoweronline.com/main/articles/five-building-blocks-of-self-powered-wireless-sensor-nodes/" rel="nofollow noreferrer">&quot;Five Building Blocks of Self-Powered Wireless Sensor Nodes&quot;</a> (shared on <a href="https://iot.meta.stackexchange.com/a/253/14">IoT Meta</a>) about energy harvesting in IoT.</p> <p>It lists a couple of harvestable energy sources for example:</p> <ul> <li>thermal energy</li> <li>vibration energy</li> </ul> <p>I am planning to implement some prototype, harvesting devices to explore the possibilities. To get some experimental data about how much energy can be harvested in my home. Currently I am trying to identify the possible spots in my home where these energy harvesters could be placed and efficiently used.</p> <p>What I though of:</p> <ul> <li>Maybe a <strong>vibration energy harvester could be attached to the washing machine</strong> in the bathroom. Risky environment as the humidity can be quite high so appropriate protection is needed.</li> <li><strong>Thermal energy harvester</strong> could be placed near the <strong>oven</strong> in the kitchen.</li> <li><strong>Thermal energy harvesters</strong> could be placed near the <strong>heating elements</strong> in the bedrooms.</li> </ul> <p>What other parts of the apartment should I place further harvesters for experimenting?</p> <p>So for example can a microwave oven be a possible source or other frequently used kitchen appliances?</p> <p>I have an electric boiler above my bathroom (inside the apartment), so maybe the hot water pipes running down to the bathroom are good sources as well.</p> <p>What else could be there? Are there any more possibilities to harvest vibration energy in a home?</p>

2017-02-15T07:47:53.037

<p>Key here is the datasheet as linked in <a href="https://iot.stackexchange.com/a/1068/54">Jimmy Westberg's answer</a>. The sensor will output: </p> <blockquote> <p>The 4-20 mA vibration transmitters are piezo-electric accelerometers of compression type and provide a 4-20 mA output signal proportional to the true RMS value of vibration velocity. </p> </blockquote> <p>So the output of this sensor is a <strong>current</strong> signal between 4 mA and 20 mA (<strong>not</strong> a voltage) that is proportional to the RMS value of vibration velocity. To read this sensors output the current will have to be converted to a voltage using a <a href="https://en.wikipedia.org/wiki/Transimpedance_amplifier" rel="nofollow noreferrer">transimpedance amplifier</a> (current-to-voltage converter) or measuring the voltage drop acros a well defined series resistor.</p> <p>However as the sensor output is the <a href="https://en.wikipedia.org/wiki/Root_mean_square" rel="nofollow noreferrer">true RMS</a> value of vibrations in the specified frequency range (2..10,000 Hz) it is not possible to obtain the frequency (or to be more precise the wide frequency band) of the vibration with this sensor. To detect the frequency spectrum a measurement of the time waveform of the vibration amplitudes would be necessary.</p> <p>This <a href="https://www.bksv.com/media/doc/br0094.pdf" rel="nofollow noreferrer">booklet about vibration measurement</a> gives some more insight.</p> <p>The RMS value is typically used in quantifying the vibration level:</p> <blockquote> <p>The RMS value is the most relevant measure of amplitude because it both takes the time history of the wave into account and gives an amplitude value which is directly related to the energy content, and therefore the destructive abilities of the vibration. </p> </blockquote> <p>The purpose of this sensor seems to be for monitoring of machinery where the actual time waveform of the vibration is of little interest. A single value (the RMS value) is sufficient to monitor the operation of the machine against a threshold value. It significantly simplifies measurement.</p> <blockquote> <p>Experience has shown that the overall RMS value of vibration velocity measured over the range 10 to 1000 Hz gives the best indication of a vibration's severity. A probable explanation is that a given velocity level corresponds to a given energy level so that vibration at low and high frequencies are equally weighted from a vibration energy point of view. In practice many machines have a reasonably flat velocity spectrum. </p> </blockquote>

|sensors|

How to calculate frequency with the voltage received from a vibration sensor?

1048

<p>I have been working on a project recently and I am using Sensor <strong>SPM SLD 723</strong> to read variations in vibrations.</p> <p>The output I received from the sensor is only in volts, how can I convert this voltage into Frequency (Hz)?</p> <p>Edit : Actual data received from Device</p> <p><a href="https://i.stack.imgur.com/Vu4H2.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Vu4H2.png" alt="list of deterioating volts from the device (from 0.16V to 0.14V)"></a></p>

2017-02-15T08:13:44.340

<p>For longer distances, I would recommend you look for a device that uses radio waves instead of Bluetooth but a word of warning, they are a bit bulkier and I'm not 100% if they make them specifically for keys but I do know a lot of the newer pet tracker are utilizing radio wave technology such was "Findster" pet tracker.</p> <p>If you insist on using something that's Bluetooth based then I would use a bluetooth tracker that has a crowdsourcing feature such as Raven Key Finder which is also a <a href="https://ravengadgets.com/products/3-in-1-bluetooth-gps-key-finder-key-tracker-phone-finder" rel="nofollow noreferrer">low energy</a> Bluetooth tracker but I think it uses Bluetooth 5.0 which might explain the extended range.</p>

|wifi|protocols|bluetooth-low-energy|lora|beacons|

Is Bluetooth a good enough protocol for "lost my keys" beacons?

1049

<p>Bluetooth beacons for localizing lost objects <a href="http://www.tomsguide.com/us/best-key-finders,review-2657.html" rel="noreferrer">are beginning to spread</a>. You can locate them using an app on your smartphone (yes, and create an account, share on facebook your objects, ...) with a closer/further logic.</p> <p>I tried one but one day my keys were in fact in my car which was out my house so detecting the beacon from my desk wouldn't work.</p> <p><strong>I was wondering if Bluetooth is such a good protocol for object location at home</strong>, especially for multiple obstacles and outdoor. Other possible networks might be:</p> <ul> <li>Wi-Fi: <a href="https://www.technologyreview.com/s/427687/if-you-have-a-smart-phone-anyone-can-now-track-your-every-move/" rel="noreferrer">You can locate people with Wi-Fi</a>, but I know <a href="https://iot.stackexchange.com/questions/66/when-to-use-wi-fi-over-bluetooth-or-vice-versa-in-an-iot-system">it is very energy greedy</a></li> <li>Z-Wave and others: there might be a signal strength capacity but is it reliable?</li> <li><a href="https://www.lora-alliance.org/The-Alliance/About-the-Alliance" rel="noreferrer">LoRa</a>: <a href="https://iotbusinessnews.com/2016/02/25/91214-wistiki-joins-the-lora-alliance-to-revolutionize-the-iot/" rel="noreferrer">a beacon manufacturer started working on it</a>, but as I heard it is not spread enough and still proprietary</li> <li>RFID and passive tags: reader are quite affordable, good candidate</li> </ul> <p>So should we stay on BT beacons or can other protocols be more reliable especially for home usage?</p>

2017-02-15T10:31:13.390

<p>The architecture which you propose seems OK. You can build more functionality on top of this, such as authentication and request sanitisation (for example time of day controls, rate limiting, etc) so it's a great example to investigate.</p> <p>There are probably some important details in the implementation which you've not looked into yet. For example, the transistor switch - this might need to be a mosfet, maybe a relay (or solid-state relay) and might have voltage and isolation issues.</p> <p>More things to consider, temperature sensing, water level (careful about contamination) and other features. RGB pod tracking (does this make it a single-use machine, or need a pod-not-replaced alarm?)</p>

|raspberry-pi|microcontrollers|wifi|esp8266|system-architecture|

Is this architecture feasible and flexible?

1051

<p>I'm having a but of trouble making sure my project really is feasible.</p> <p>What I want to archive: Control my Senseo coffee machine via internet. It boils down to simply controlling 2 buttons.</p> <p>First easy solution:</p> <ol> <li>Setup a NodeJS server on my Raspberry Pi.</li> <li>I plug my Raspberry GPIOs to 2 transistors, to control the coffee machine buttons</li> <li>I can control the Raspberry GPIO directly in Javascript. For example calling <a href="http://myraspberrypi.com/makemeacoffee" rel="noreferrer">http://myraspberrypi.com/makemeacoffee</a> activates the GPIO, activates the buttons, and the coffee flows</li> </ol> <p>But: <strong>I don't want to plug my raspberry to my coffee machine</strong> (I need the Pi for other purposes), and I think that decoupling the web server and the controller itself is a good idea. If tomorrow I want to monitor the temperature of my bathroom, or control a second coffee machine (using another ESP8266) I want be able to do it without rethinking the whole thing.</p> <p>What I need to archive that is an ESP8266 with NodeMCU to use it as a Wi-Fi headless controller (see <a href="http://www.instructables.com/id/ESP8266-Web-Server-Without-Arduino/" rel="noreferrer" title="this link">this link</a>). Raspberry GPIO are no longer used (that's the point). There is only a NodeJS web server on the Pi.</p> <p>Here is a quick sketch of the architecture: <a href="https://i.stack.imgur.com/qHkhc.png" rel="noreferrer"><img src="https://i.stack.imgur.com/qHkhc.png" alt="is this architecture feasible ?"></a></p> <p>Let me clarify the role of the main components: </p> <ul> <li>Raspberry Pi: Hosts the NodeJS web server</li> <li>NodeJS web server: Serves the web pages to the end user. Basically a page with a button "Make me a coffee". Behind the scene, we need to "push" the heat up the water button, wait 30 sec, then "push" the coffee button. The web server does so by sending HTTP requests to the ESP8266 (over Wi-Fi). The NodeJS server also does logging and data analysis (how many coffee did you drink this year ?)</li> <li>ESP8266: Uses NodeMCU. Its GPIOs are plugged to a transistor controlling the coffee machine buttons. I don't care about how to power the ESP8266. It runs a web server to listen to the Raspberry Pi requests and do actions on GPIOs accordingly.</li> </ul> <p><strong>Is this architecture feasible? Is this architecture flexible?</strong></p> <hr> <p>EDIT, to answer Sean Houlihane (spoiler to keep the post relatively short):</p> <p>I'm not 100% sure about this, but a transistor is seems to be enough. The coffee machine switch is working on low voltage (3,3V) and the ESP8266 won't share the ground with the coffee machine.</p> <p>About the temperature sensing, and the water level control, the Senseo coffee machine has this built-in. Typical use : Press the center button to launch the heat up process, choose your coffee size by pressing the "single" or "double" button. Once the heat up process ends, the coffee starts flowing. If there is not enough water, it ends and a LED blinks.</p> <p>The progress I expect : </p> <ul> <li>Version 1.0 will be "Just run the coffee machine, I am sure it's ready". I control the single cup button and the heat up button.</li> <li><p>Version 2.0 will be "Run the machine and give me feedback" I had another ESP8266, plugged to the feedback LED (So that I can know when it's heating up and when it's out of water) and another one to a scale to make sure the cup is there before running the coffee machine. I might also add an alert when the coffee machine is ran to tell the user to change the pod.</p></li> <li><p>Version 3.0 will be to find a way to tell if the pod has been changed, by tracking the opening of the mechanism with some kind of switch. But this is out of the scope of my project at the moment.</p></li> </ul>

2017-02-15T14:58:53.660

<p>Yes, there already are such devices.</p> <p>If you are not bound to the rotary dial there are dimmers out there (e.g. <a href="http://www.smarthome.com/switchlinc-dimmer-insteon-2477d-remote-control-dimmer-dual-band-white.html" rel="nofollow noreferrer">Insteon 2477d</a>). Probably there some rotary versions too. The Insteon variant can be controlled via their powerline messages (<a href="http://cache.insteon.com/pdf/insteondetails.pdf" rel="nofollow noreferrer">Spec</a>) or via a hub. According to the Insteon website you could build your own powerline client, hook it up to a Pi, a computer or whatever else you want and communicate with your dimmer switch. It's also dual band. Although the second band is RF and not Wi-Fi and thus not terribly helpful.</p> <p>However as far as hubs go the <a href="http://www.smarthome.com/insteon-2245-222-hub.html" rel="nofollow noreferrer">hub</a> is not terribly expensive and bridges over to Wi-Fi and has a HomeKit and Alexa integration.</p> <p>If you want to connect an existing rotary dimmer to the IoT a bit of electrical engineering will be required.</p>

|smart-home|communication|system-architecture|lighting|

Can a dimmer switch be connected to the IoT?

1054

<p>I'd like to connect a button "dimmer switch" like this one:</p> <p><a href="https://i.stack.imgur.com/gyl1U.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gyl1U.png" alt="picture_of_a_rotary_dimmer_ligts_and_a_living_room"></a></p> <p>to the IoT. Maybe there's already such a device, I just could not find any.</p> <p>The underlying idea is to set a "%" information for each of these devices, transforming it in a sort of manual sensor, and collecting it over the network.</p> <p>As I am just beginning to get the concepts of IoT, my naive expectation is that this kind of sensor would exist, connected and <strong>integrated</strong> to an IoT enabled Linux based operating system, point from which I would know what to do onward. I just am completely lost about the connection between the electronics and O/S. I am willing to store in a database the % value (or "dim level"?) of several of these sensors, connected to a given network through a yet-to-determine technology and protocol. Some dashboards would then connect the database and show the information along with some analytics.</p> <p>Either way, any advice on how to proceed would be great!</p>

2017-02-16T16:04:19.480

<p>I'd go for OwnTracks (iOS + Android) which lets your phone send GPS-data over (preferably MQTT) the internet. You may set up this to poll your phone and let a server see if the signal is approaching the house which indicates that the phone is traveling in a car or the best would be to have an (old) phone inside the car at all time which only is used as a locator for the car.</p> <p><a href="http://owntracks.org/" rel="noreferrer">Here's the link to the app that I use.</a></p> <p>You may also want to use the <a href="http://owntracks.org/booklet/guide/beacons/" rel="noreferrer">Beacon function within OwnTracks</a> which lets your phone know that it is in the car if it is close to the car Beacon. <a href="https://www.aliexpress.com/item/IBeacon-bluetooth-4-0-BLE-module-near-field-orientation-commercial-WeChat-shake-around-wireless-base-station/32651610552.html?spm=2114.01010208.3.46.4unLBG&amp;ws_ab_test=searchweb0_0,searchweb201602_5_10065_10000073_10068_10000077_10000074_10000032_119_10000030_10000026_10000023_431_10000069_10000068_10060_10062_10056_10055_10000062_10054_10000063_10059_10099_10000020_10000013_10103_10102_10000016_10096_10000056_10000059_10052_10053_10107_10050_10106_10051_10000097_10000094_10000091_10000007_10000050_10084_10000101_10083_10000100_10080_10000047_10000104_10082_10081_10110_10111_10112_10113_10114_10000089_10000086_10037_10000083_10033_10000041_10000044_10000080_10078_10079_10077_10000038_10073_10000035_10070_10122_10123_10121_10126_10124,searchweb201603_10,afswitch_3,ppcSwitch_5,single_sort_1_default&amp;btsid=15893d06-2387-4918-9ff6-c07bdf9a5cf7&amp;algo_expid=c823f32a-ff9d-4580-97c4-f3e9b0d09dfd-5&amp;algo_pvid=c823f32a-ff9d-4580-97c4-f3e9b0d09dfd" rel="noreferrer">You find them online here</a> <a href="https://www.aliexpress.com/item/CC2541-Beacon-bluetooth-module-build-in-iBeacon-firmware-and-Coin-type-cell-transposon/32700900717.html?spm=2114.01010208.3.46.j0Byk6&amp;ws_ab_test=searchweb0_0,searchweb201602_5_10065_10000073_10068_10000077_10000074_10000032_119_10000030_10000026_10000023_431_10000069_10000068_10060_10062_10056_10055_10000062_10054_10000063_10059_10099_10000020_10000013_10103_10102_10000016_10096_10000056_10000059_10052_10053_10107_10050_10106_10051_10000097_10000094_10000091_10000007_10000050_10084_10000101_10083_10000100_10080_10000047_10000104_10082_10081_10110_10111_10112_10113_10114_10000089_10000086_10037_10000083_10033_10000041_10000044_10000080_10078_10079_10077_10000038_10073_10000035_10070_10122_10123_10121_10126_10124,searchweb201603_10,afswitch_3,ppcSwitch_5,single_sort_1_total_tranpro_desc&amp;btsid=b7604933-70fd-4c9e-a66e-1c64550cee35&amp;algo_expid=5ed32357-7229-4c30-a173-7809406b1af1-5&amp;algo_pvid=5ed32357-7229-4c30-a173-7809406b1af1" rel="noreferrer">and here</a>.</p>

|sensors|smart-home|

Automatically open a garage door when approaching by car?

1060

<p>There is this thing I noticed in my neighborhood: when Sam is waiting for his not-so-automatic door to open, he stops the traffic for 20 or 30 seconds, due to the street configuration.</p> <p>I want to buy a house in this neighborhood (I now own a flat there), and the seller already installed an automatic door with an infrared remote control, making the sell easier and faster. Please understand here that I am not able (and I do not want to) choose or change the automatic door model, otherwise I would have picked up some pre-equipped IoT-ready model.</p> <p>I do not want to be like Sam and be a pain in the ass to every other driver in this street, and I am looking for any idea to be able to remotely/automatically open the door when getting close (like 150-200m) to my house.</p> <p>You can assume that, once the house "knows" I am approaching, it can open the door. What I am looking for is a way to let my house know that I am approaching. Plus, if a car is already parked in my garage (like my wife's car), the door won't open. There is obviously safety-issue there (like a door giving access to my house when no one in front of it), but I do not want to deal with this right now.</p> <p>Thanks for your help of for any idea you can give!</p>

2017-02-18T18:15:51.517

<p>One of the key issues with My Friend Cayla is that the audio files it sends are not saved securely. <a href="https://twitter.com/TheKenMunroShow" rel="noreferrer">Ken Munro </a> has carried out extensive analysis on this (and many other IoT devices) and points out that the audio files are available on the Internet, with poor access controls!</p> <p>So not only is everything your child says going to a server somewhere, others can listen to it...</p> <p>(piece of advice - for IoT security, follow Ken Munro. You'll be surprised at the access he gains to not just IoT devices, but through them to home computers, passwords and more!)</p>

|privacy|smart-toys|

Why was the Internet-connected My Friend Cayla doll banned as a "hidden espionage device"?

1074

<p><a href="https://www.cnet.com/news/parents-told-to-destroy-connected-dolls-over-hacking-fears/" rel="noreferrer">According to CNET</a>, the My Friend Cayla doll was banned in Germany because it has been classed as an illegal &quot;hidden espionage device&quot;:</p> <blockquote> <p>If you're considering purchasing a connected toy for your offspring, you might want to think twice.</p> <p>In Germany, regulators have determined that the My Friend Cayla doll could be up to no good, given its potential to steal information about children who play with it. And they say that German parents whose children are in possession of a Cayla doll should destroy the toy.</p> <p>The Federal Network Agency said in a press release Friday that it has removed Cayla dolls from the market in Germany and will not look to prosecute parents who have purchased one. It does expect, however, that parents who have bought a doll will assume responsibility for destroying it.</p> <p>Cayla dolls, which incorporate microphones and ask kids questions about themselves and their parents, are classified as &quot;hidden espionage devices,&quot; the possession and selling of which are banned by German law.</p> </blockquote> <p><a href="https://iot.stackexchange.com/questions/273/how-to-stop-these-toys-from-sending-what-my-kids-say-to-the-cloud">I did a bit of research about the toy previously</a> when someone asked about the toy, and although it does seem slightly inappropriate to be sending your children's speech to a cloud server, it's not exactly <em>hidden</em>; the device is advertised as 'smart' and connected to the Internet.</p> <p><strong>Are there other flaws with the doll that made it illegal (hacking, maybe?), or was it banned simply due to the privacy concerns of sending data to the manufacturer?</strong></p>

2017-02-20T08:23:28.207

<p>Building upon several years of deploying outdoor wireless sensor networks, I would like to add the following hint:</p> <p><strong>Think ahead and do not underestimate the problems arising from humidity!</strong></p> <p>I will answer your question by providing some pitfalls with humidity in outdoor devices. However, please consider these <a href="https://iot.stackexchange.com/questions/1115/what-should-be-considered-when-building-a-wireless-sensor-network/1116#1116">general guidelines when planning a wireless sensor network</a>.</p> <p>It is very simple to build a housing that keeps the rain from falling onto your sensor, but as @Ghanima pointed out it very much depends on what you really want to measure.</p> <p>However, the main problem is not rain but humidity. This is roughly what happens with not properly constructed devices in outdoor environments, starting with a dry housing:</p> <ol> <li>The outdoor temperature rises. The temperature of the air in your device rises even more (especially when placed in the sun).</li> <li>Therefore, the air pressure in your device rises, it expands and some part diffuses out of the device.</li> <li>The temperature falls. Thus humid (!) air diffuses back into the device. </li> <li>The humid air condensates inside the device.</li> <li>The cycle repeats, but the temperature inside the device is not high enough to evaporate the water again. Therefore, water accumulates inside the device. Every day a very tiny amount of water is added.</li> </ol> <p>Several possible approaches to counteract this problem:</p> <ul> <li><p><strong>Sealing the device</strong> Trust me, that does not work with household items. Even if your freezer box has a seal and silicone works good in the bathroom, both do not prevent the flow of humid air! Dipping the device into water without any water coming in, does not mean that humid air will stay out, too! If you want to go that way, buy industrial grade (IP rated) housings and do not drill additional holes into it!</p></li> <li><p><strong>Drilling a hole into the bottom</strong> What, you just said the opposite? The reason is simple: If you can not avoid that humid air comes into your device, you should at least avoid that water accumulates inside. For many electronic components <em>some</em> humidity is not such a big problem, but accumulating water is!</p></li> <li><p><strong>Air-conditioning</strong> Heating up the device prevents condensation. This is the common approach for large and sensitive outdoor devices, especially if the condensation itself induces problems (for example for optics).</p></li> <li><p><strong>A pressure-compensating diaphragm</strong> Not that cheap but works quite good in practice by equalizing the air pressures. There are also cable feed-throughs with an integrated diaphragm.</p></li> </ul>

|sensors|wireless|

Temperature sensors affected by rain

1085

<p>I am not sure if this is the best place to ask a question like this. </p> <p>I am working with a wireless sensor network that measure temperature, humidity and illuminance. I have read that outside sensors, should be located in a place where rain does not hit them. </p> <p>I do not know why should I do this. How are these sensors affected by rain? Has anyone faced this problem before?</p>

2017-02-21T17:40:05.290

<p>There are many factors in choosing whether to process data on-device or in the cloud.</p> <h1>Benefits of processing in the cloud</h1> <ol> <li><p>If the algorithm uses floating-point or runs on a GPU, it might not be possible to run on the embedded processor in the sensor.</p></li> <li><p>Even if it doesn't, if the algorithm was developed in a high-level language, it might be too expensive (in developer time) to port it to run on the sensor.</p></li> <li><p>Offloading computation from the sensor may increase its battery life (depending on how this affects network/radio use).</p></li> <li><p>Running the algorithm in the cloud allows it to combine the data from many sensors and make a system-level decision. In this example, that might mean filtering across different cars' sensors, so that washing one car doesn't cause a rain warning in every car.</p></li> <li><p>Processing in the cloud allows to distribute the information to many places without having to have a mesh network, which is a complicated architecture.</p></li> <li><p>You can log more data, which enables better analytics, audit, and development of better algorithms.</p></li> </ol> <h1>Benefits of processing on-board</h1> <ol> <li><p>If the raw sensor data is high-bandwidth, it might use less battery to summarise the data and send the summary (depending on what processing is needed to <em>summarise</em> it). This might mean that instead of sending an 8-bit moisture reading 100 times a second, you filter it and send a 1-bit wet/dry flag every 10 seconds.</p></li> <li><p>You might go further, and only wake up the network at all when the sensor has something interesting-looking to report (e.g. the wet/dry state changes)</p></li> <li><p>Reducing the network bandwidth at the sensor end also reduces it at the server end, so you can scale the service to more users (more sensors) very cheaply.</p></li> <li><p>It might be possible to run the service with the same or reduced functionality even when the network is unavailable. In this example, your car might be able to warn you about slippery roads it sees itself, but not give you advance warning from other cars.</p></li> </ol> <h1>Overall</h1> <p>Usually, some combination of the two is optimal. You might do as much processing as you can afford to do on the device, to reduce the need for the network as much as you can, and then run more sophisticated algorithms in the cloud that can combine more inputs or use more compute power.</p> <p>You might start out running all of your processing in the cloud (because it was prototyped in Matlab or Python) and port parts gradually to Rust to enable offline functionality, when you have developer time to spend on it.</p> <p>You might process the data heavily on the device in normal use but also sample and log the raw data sometimes, so that you can upload it to the cloud later (when network is more available) for your analytics.</p>

|sensors|aws-iot|cloud-computing|

Why might data be sent to a cloud service when it could be processed on the edge?

1090

<p>I was recently reading Amazon's information about the <a href="https://aws.amazon.com/iot-platform/" rel="noreferrer">AWS IoT Platform</a>, and came across an interesting example use case:</p> <p><img src="https://d0.awsstatic.com/Test%20Images/MasonTests/IceX_3Connected.png" alt="Example of using AWS IoT to detect moisture for car safety"></p> <p>Although they don't describe how exactly the road condition data is sensed, if the sensor <em>can</em> detect a wet road, why would Amazon suggest sending the data to the cloud? Wouldn't it be simpler just to directly process the sensor data on the vehicle and alert the driver, rather than sensing, sending data to the cloud, waiting for it to be processed, receiving data and <em>then</em> alerting the driver? I can't really see much of an advantage other than the possible analytics data you would gain.</p> <p><strong>Is Amazon's example use case only beneficial when you want to gain analytics data, or are there other reasons that they would suggest to use the cloud?</strong></p> <hr> <p>^{I suspect one of the reasons is simply to make people use the service they're trying to sell, but I'm interested in <em>technical</em> reasons, if there are any.}</p>

2017-02-21T19:29:28.017

<p>After doing some further research, I'm pretty sure <a href="http://docs.aws.amazon.com/iot/latest/developerguide/thing-types.html" rel="nofollow noreferrer">Thing Types</a> <strong>are</strong> what you want.</p> <blockquote> <p>Thing types allow you to store description and configuration information that is common to all things associated with the same thing type. This simplifies the management of things in the thing registry. For example, you can define a LightBulb thing type. All things associated with the LightBulb thing type share a set of attributes: serial number, manufacturer, and wattage. When you create a thing of type LightBulb (or change the type of an existing thing to LightBulb) you can specify values for each of the attributes defined in the LightBulb thing type.</p> </blockquote> <p>Thing Types do not mean all the devices are treated as <strong>one device</strong>; each Thing receives its own <a href="http://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html" rel="nofollow noreferrer">ARN</a> regardless of whether it has a Thing Type or not.</p> <p>Each Thing should be able to subscribe to a custom <a href="http://docs.aws.amazon.com/iot/latest/developerguide/topics.html" rel="nofollow noreferrer">topic</a> (if you're using the MQTT broker), even though it has a Thing Type. The only difference is that Things with a Thing Type are given certain (immutable and fixed) attributes which can define properties for that particular type of Things.</p> <p>If you want to send messages from all your Things as if they are one, just publish to a common MQTT topic not specific to one device.</p>

|aws-iot|aws|

When setting up 'Things' in AWS IoT, can I have one thing, and then have many instances of that Thing?

1092

<p>I might be putting this into software terms, but I just want to have all my things be the same type, but have multiple instances (multiple things). Each thing must be able to be referenced individually as well, and individually subscribe to messages. Then, I could have multiple Raspberry Pi's send data back to AWS-IoT while also each could subscribe to a unique message. Thank you.</p>

2017-02-21T19:44:19.047

<p>Could you make custom rule by typing the ports (1883 and 8883) and allowing separately with different rules both UDP and TCP on these ports.</p> <p>See: <a href="https://technet.microsoft.com/en-us/library/cc947814(v=ws.10).aspx" rel="noreferrer">https://technet.microsoft.com/en-us/library/cc947814(v=ws.10).aspx</a></p> <p><a href="https://www.sevenforums.com/system-security/214964-firewall-rule-unable-change-scope-tcp-udp-rules.html" rel="noreferrer">This</a> post says you need the described hack that did not work in your case to change the defaults by program name.</p>

|security|mqtt|mosquitto|microsoft-windows|whitelisting|

How to modify Mosquitto's Windows Firewall Inbound Rule to only allow connections from specific IP addresses?

1093

<p>I am trying to set up IP whitelisting for my Mosquitto broker on Windows 7. To do so I have performed the following steps, based on this article: <a href="http://support.hostgator.com/articles/how-to-whitelist-your-ip-windows-dedicated" rel="nofollow noreferrer">How to Whitelist Your IP - Windows Dedicated</a>.</p> <ol> <li>Open <strong>Windows Firewall With Advanced Security</strong> from <strong>Start</strong>.</li> <li>Select <strong>Inbound Rules</strong> from the list on the left.</li> <li>Search for the rules called "mosquitto" there are 2-2 for TCP and UDP. (I do not know why there are two for each.)</li> <li>Open <strong>Properties</strong> of the mosquitto TCP rule.</li> <li>On the <strong>Scope</strong> tab, on <strong>Local IP address</strong> section select the <strong>These IP addresses</strong> and add the specific IP address. 192.168.1.5 in my case.</li> </ol> <p>First I have received the following error.</p> <p><a href="https://i.stack.imgur.com/5shZn.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5shZn.png" alt="Picture of windows firewall error message reporting wrong parameter"></a></p> <ol start="6"> <li>To solve it, the <strong>Edge traversal</strong> settings has to be modified on the <strong>Advanced</strong> tab. I have changed it from "Defer to user" to "Block edge traversal."</li> </ol> <hr> <p>Conclusion. It does not work, I cannot connect to the broker from the 192.168.1.5 address. It is all the same if I select the "Allow edge traversal" option.</p> <p>Once I switch back to the "Any IP address" my client connects without any problem.</p> <p>What's wrong?</p>

2017-02-22T09:41:21.273

<p>Arduino is an open source platform for IoT test projects, and you'd buy either a Arduino device or a cheap derivation, that may have cheaper price or better characteristics.</p> <p>Same Arduino IDE can be used for all variations, you'll use IDE to install the software and test your programs. Program has one time and loop parts where you can build your stuff by C++ like language.</p> <p>C++ basics on memory usage may be useful for programming language side.</p> <p>With more electronics skills you may also develop your own circuits for device, it is possible by the licence.</p> <p>[1] <a href="https://www.arduino.cc/en/Guide/Introduction" rel="nofollow noreferrer">https://www.arduino.cc/en/Guide/Introduction</a></p> <p>[2] <a href="https://www.arduino.cc/en/Guide/windows" rel="nofollow noreferrer">https://www.arduino.cc/en/Guide/windows</a></p> <p>[3] <a href="https://en.wikipedia.org/wiki/List_of_Arduino_boards_and_compatible_systems" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/List_of_Arduino_boards_and_compatible_systems</a></p>

|networking|hardware|communication|

How to start IoT development to send commands from IoT Hub to Device

1099

<p>I'm a .Net developer recently started working on WindowsAzure IoT, but my role is just creating web API's to provide data to client (Mobile App) sent by IoT devices.</p> <p>I want to send commands to devices, instead of just receiving data sent by devices. You can say that I just want to work on a simple demo project as startup, so I will get to know how IoT works real time and what is the exact flow of communication between IoT Hub and Devices.</p> <p>My questions are :</p> <ol> <li><p>Which is the best Open Source/Free Trial <strong>IoT Hub/Platform</strong> to use (Already used WindowsAzure trial and it's expired, so it's not in option).</p></li> <li><p>Which is the best <strong>Programming Language</strong> to use for this demo, I think language will depend on which IoT Hub we choose, if I'm not wrong (Already have knowledge of C#, JavaScript and SQL Server in database, but I'm ready to learn new language if required)</p></li> <li><p>Which <strong>Device</strong> is cheap and best for this demo</p></li> <li><p>The most important, where to check <strong>Step by Step Tutorial</strong> for development.</p></li> </ol> <p>Any help is appreciated ...</p> <p>Feel free to ask if you have any doubt related to my query.</p>

2017-02-22T17:22:04.787

<p>You've questioned both previous answers about the need for a controller/hub. Consider that to make things happen, you need rules to exist. If you want to push a big red button to open a garage door, some rule has to tie the sensor (button) to the desired action (opening the door). There are two ways to make that happen: you can put the rule directly in the button, or you can put the rule in a separate computer.</p> <p>Let's think more about the direct solution. If you teach the button about the garage door, then your button holds the rules internally. The button needs the ID of the garage door, so if you replace the garage door, the button doesn't work. If the button is on your desk, and your house uses a proprietary network, the button has to know both the address of your home's gateway and the address of the door. The button needs to know the specific protocol to signal your door to open - do all manufacturers make compatible buttons that know about all door signals? The button can't do anything else unless you reprogram it - do you have a flash programmer for the button's chip laying around, and is that programmer compatible with any other devices? If you want the garage door to open, and 5 minutes later close, your button needs all the complexities of maintaining a real-time clock. Your button won't know the state of the door, making it hard to know if you're closing the door or opening it. And how do you back up the rules so that if your button breaks, your replacement button can do the job? On the plus side, it sounds cheap: you don't need a separate computer. </p> <p>With a controller, things are different. All messages from all sensors are delivered to the controller. Each sensor is simple: send the signal to the controller. The controller can then apply whatever inputs are needed to very complex rules: it can check the sunshine sensor and not turn on the outdoor lights unless it's dark, or not run the sprinklers if the average rainfall for the month is above average and the current temperature is five degrees below average. The controller can keep track of state. This could be important if you want a "close garage door" button but not an "open garage door" button (when I'm away from home, I rarely want to open the door, but I definitely want to close it if it is accidentally left open.) </p> <p>The controller can provide the place for device drivers that know how to listen to buttons and other drivers that know how to speak to doors. The controller may be more upgradeable to new devices and device types than a tiny chip tucked inside a button. </p> <p>The controller can also have more complex logic for infrastructure tasks such as delivering messages by offering certain levels of service. For example, the MQTT protocol allows for three different levels: try to deliver the message once, deliver it repeatedly until it's been seen at least once, or deliver it once and only once.</p> <p>The controller offers an architecturally logical place to consolidate all messaging to and from a communication gateway, allowing the use of an external interface. This means your button and your phone can both send signals, and the rules can figure out that either one is allowed to open the garage door. The gateway can also provide the security. You don't have to put your button and your garage door on the internet; you can put them both on private isolated networks and use the gateway to carry the signals. The controller also provides a single point to back up all the rules for your system. </p> <p>The downsides to the controller are added latency and extra complexity. Surprisingly, a controller doesn't make the cost go up appreciably. You can implement a controller on a Raspberry Pi for less than the cost of one average remotely controllable light switch. Don't discount the idea on the basis of cost alone.</p>

|networking|microcontrollers|

What do I need to create my own personal cloud for IoT devices?

1104

<p>This is a subject I have been thinking of for a while, especially because the "IoT" concept has been floating around a lot lately.</p> <p>I will start with what I mean when I say <strong>"IoT"</strong>. I know that the term IoT could mean different things and that sometimes it's misused. It could be a term that is not clearly defined and can lead to big discussions around what does it exactly mean, I myself don't know the proper and widely accepted definition of the term. <strong>So for me IoT is a concept, a concept that defines the ability to connect to an embedded device remotely through the internet either from another embedded device or from a cell phone</strong>. As simple as that.</p> <p><strong><em>On this context, the purpose of the connection doesn't matter, if you can connect one device in your office with another one at home, or if you can connect to one device at home from your cell phone, all this through the internet, then we are talking about IoT devices</em></strong> (the embedded devices, not the phone).</p> <p>So, having agreed on what I mean by IoT I will now describe what I'm trying to achieve.</p> <p>What I'm trying to achieve is precisely that what I describe on my definition of IoT.</p> <blockquote> <p><strong>I want to have one or several embedded devices at home connected to my internet router, either by ethernet or wifi and be able to connect to them remotely with another embedded devices in a remote location (and by remote I mean not on the same network) and maybe also to be able to connect to them with a monitoring app on my phone</strong></p> </blockquote> <p>For example, I may have a simple embedded device acting as an on/off switch hooked op to my garage door opener and another embedded device acting as a big red button on my desk at work so that I can push the red button in my desk and the garage door opens.</p> <p>Another example would be to have an embedded device with ADC capabilities that can monitor the temperature of my house and send me an alert when it reaches a threshold. The notification could be received either by a simple android app or by another embedded device with a little screen sitting on my desk at work.</p> <p>These examples may be silly but are just to illustrate the possible scenarios and use cases for what I'm trying to achieve. At the end, the idea is the same, connect one embedded device with another through the internet.</p> <p><em>Another thing to clarify is that the data exchange between these devices will be very lightweight, just a couple of bytes every time, it is not that hundreds of kilobytes are needed to be interchanged between devices.</em></p> <p><strong>Additionally, the kind of "embedded devices" I'm referring to are simple but capable devices based on 100MHz or 200MHz cortex-m4 microcontrollers. And that is important to clarify because there won't be any Linux or complex libraries running on those devices. In the end, is such a waste of resources and completely unnecessary to have a powerful processor running Linux just to turn on and off a light bulb</strong>. In any case, I'm planning to use a BeagleBoard, Raspberry Pi, or any other board like that as my embedded devices. Just Microcontrollers because no more complexity than that is needed.</p> <p>I don't know much about IoT platforms and those kinds of complex solutions out there. When I started this journey of finding out a way of connecting one embedded device with another through the internet I stumbled upon a couple of sites with IoT services.</p> <p>I know that there are some IoT cloud services like:</p> <ul> <li><a href="https://www.kickstarter.com/projects/167134865/blynk-build-an-app-for-your-arduino-project-in-5-m" rel="noreferrer">Blynk</a></li> <li><a href="https://cloud.google.com/solutions/iot/" rel="noreferrer">Google Cloud Platform</a></li> <li><a href="https://exosite.com/platform/" rel="noreferrer">Exosite IoT Platform</a></li> <li><a href="https://www.aylanetworks.com/products" rel="noreferrer">Ayla IoT Platform</a></li> </ul> <p>Just to name a few. The main issues with those are cost and complexity. You have to pay to get those services and also you have to learn how to implement all the services they have, in case you need them all, and their APIs and maybe a bunch of other stuff that doesn't seem necessary to me to be able just to interchange some bytes between devices. I just want something simpler than that, something I can do myself.</p> <p>You may say that implementing my own "cloud", if that is something I have to do, is not simple and sometimes is better to use those kinds of services for the sake of simplicity but there are two main reasons I want to know how to implement my own IoT services.</p> <p>The main reason is that I want to do it myself. I don't want to rely on a 3rd party to connect my devices to each other and since I'll be developing the code and the hardware for my devices then it feels better to also create my own means to connect them as IoT devices.</p> <p>The second reason is to learn how to do it. By knowing all the necessary things I need to achieve this, I will have a better understanding about the IoT world.</p> <p>Also, I want to mention that I'm proficient in C and I use Linux as my everyday OS at work as well as in my home, so please avoid windows stuff because that is useless to me. I'm not afraid of anything I have to implement in C for my embedded devices or on Linux to implement whatever is needed to achieve my goal.</p> <p>So my question is, <strong>what is it necessary to implement, and where, to be able to connect two or more embedded devices to each other with the purpose of data interchange between them?</strong></p> <p>This question <a href="https://iot.stackexchange.com/questions/756/what-can-i-use-to-create-an-iot-on-our-own-server">What can I use to create an IoT on our own server?</a> have something similar but is closed and doesn't have any answers, also assumes an already existing cloud infrastructure to be used. So it doesn't help me.</p> <p>This other post <a href="https://iot.stackexchange.com/questions/600/what-iot-services-are-available-for-storing-sending-publishing-generic-data-in-t?noredirect=1&amp;lq=1">What IoT services are available for storing/sending/publishing generic data in the cloud?</a> has a similar question but the OP is asking explicitly for IoT services and I'm trying to avoid those.</p>

2017-02-23T08:48:25.077

<p>Another approach is to buy the components and make them run,and then you decide what do to with the them. Surely you will come up with ideas while developing</p> <p>You can start with one of the adfruits kits.</p> <p><a href="https://www.adafruit.com/" rel="nofollow noreferrer">https://www.adafruit.com/</a></p> <p><a href="https://i.stack.imgur.com/hHjIu.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hHjIu.jpg" alt="Adfruits for raspberry pi"></a></p> <p>Once you can control the I/O then the path to the remote control from the server is quite straightforward. You start turning On/Off LEDs then you can add relays and power something bigger, a Fan, Lights, motors, water pump... etc</p>

|software|

Seeking an idea for an IoT project to keep me occupied

1108

<p>I have been coding embedded systems for (*cough*) decades now. Mainly telecomms &amp; satcomm, with some telemetry &amp; SCADA. I can also produce Windows, Linux &amp; browser based apps and have good database knowledge.</p> <p>Sound like prime IoT developer material? I also have some free time, so, to keep me out of the pub, I would like to start a project. </p> <p>I would prefer something which grows in phases. Maybe develop the server, then the clients, then some browser-based reporting, maybe some test tools. Perhaps a phase one with minimal functionality, then phase two adding more features, etc</p> <p>I would like something to occupy my evenings and weekends for months, maybe years. I am undecided as whether to develop something open source, or something where I stand a slim chance of turning a shilling.</p> <p>The one Teensy flaw in my grandiose scheme is that I haven’t go the faintest glimmer of an inkling of the beginning of the kernel of a close as what to develop.</p> <p>Does anyone have a suggestion for me (preferably not involving <a href="https://iot.stackexchange.com/questions/675/extreme-modification-suggestions-for-a-wi-fi-enabled-hairbrush">hairbrushes</a>)?</p>

2017-02-23T09:59:34.987

<p>John is on to a solution that should work. Another alternative is to run all your IoT devices on a WiFi guest account, and everything else on the main account/password. This is a simple way to separate your smart devices from your computer network. It's a less sophisticated method of security but a lot easier to implement.</p>

|networking|security|wifi|

Connect IoT devices directly to Wi-Fi , through VLAN or through a Raspberry Pi?

1112

<p>I have a bunch of IoT switches connected to my Wi-Fi.</p> <p>I am aware of three possibilities to connect and control them.</p> <ol> <li>Through the Wi-Fi directly (like Samsung SmartThings does)</li> <li>Connect them to a personal VLAN and use them (seems more secure).</li> <li>Connect all the devices to a Raspberry Pi (or something similar) like a master and connect the devices to it.</li> </ol> <p>Which one would be the safest (most secure for IOT) comparatively?</p> <p>Are there any better solutions and how difficult would each one be?</p>

2017-02-23T16:05:28.480

<p>Please do not waste your time and make the same mistake as hundreds of research groups (including ours) made before for decades and just throw some unspecific sensors into the wild without knowing what you really want to get in the end!</p> <p>There is <a href="https://www.st.ewi.tudelft.nl/%7Ekoen/papers/WPDRTS06.pdf" rel="nofollow noreferrer">a nice paper from 2006</a> (!) that shares experiences from a real-world deployment.</p> <blockquote> <p>Langendoen, Koen, Aline Baggio, and Otto Visser. &quot;<strong>Murphy loves</strong> <strong>potatoes: Experiences from a pilot sensor network deployment in</strong> <strong>precision agriculture.</strong>&quot; 20th International Parallel and Distributed Processing Symposium (IPDPS) 2006.</p> </blockquote> <p>Be prepared for those and many other problems that could arise and <strong>plan ahead and focus on your target!</strong></p> <p>You should ask yourself the following question: Why do I want to build the deployment? Is it really the data itself that I want to collect, do I want to evaluate and develop network protocols or do I want to develop and test new hardware? The answer results in very distinct paths:</p> <h3>I want to get the data!</h3> <p>In that case, try to rely on proven practices as much as you can. Buy standard hardware, use industrial grade housings, provide much more batteries than you think your hardware requires and monitor them! Use already existing and well-tested software and do not build everything from scratch! Even think about the following: Do I <em><strong>really</strong></em> need wireless connections?</p> <p>Of course, there are many applications where you really need hundreds of energy harvesting, wireless, self-organizing and tiny devices. But just using these techniques because they are <em>cool</em> is a waste of money and time.</p> <p>If you really want to get the data, nothing is more frustrating than to notice that just for the most interesting day, no data is available because water has accumulated in your devices (been there...).</p> <h3>I want to improve protocols for wireless sensor networks!</h3> <p>In that case, really focus on the core. I talk about network protocols here, but it equally holds for all other procedures and algorithms in the IoT context.</p> <p>For most protocols, it does not care if they transport real-world data or just some pseudo-random noise. So why not take the easy road, throw away your sensors and just generate some random data? I recommend the following procedure:</p> <ol> <li>Think about which problem you want to solve. What is your research question?</li> <li>Read! Many things have been done already. Many concepts have been shown to be good, many others not. Starting with network protocols from scratch is just a waste of time.</li> <li>Do some theoretical evaluations. Is it really possible to improve a given protocol or is it already at a principle boundary? Shannon can not be fooled!</li> <li>Do simulations. I suggest the OMNeT++/INET framework, but there are many frameworks out there. But please do not start from scratch. Most components are already there for your convenience. Test if your ideas work in the controlled environment of a simulator.</li> <li>Work on the hardware implementation. Does your implementation work at least on your desk?</li> <li>Test it in an already existing testbed. One example is the <a href="https://www.iot-lab.info/" rel="nofollow noreferrer">FIT IoT-LAB</a>. This allows you to test your implementation with real-world hardware without the burden of all the problems arising from self-made testbeds.</li> <li>Now you can finally plan your real-world deployment and tailor it to the specific problem that you want to address. Until now you should have a good idea how dense your network has to be, how many devices are meaningful, how they should be distributed, which kind of data has to be provided and so on. Then go to &quot;I want to get the data!&quot;, but this time your data is the performance measure that you want to test.</li> </ol> <p>Yes, this is a long way to go, but there are students doing this during a six-month master's thesis, so it is feasible and definitely worth the effort! There is already so much existing research in this area that skipping a step does not pay off in the end.</p> <h3>I want to build cool hardware!</h3> <p>If you are mostly interested in building cool hardware, start with playing around with existing hardware. Then think about what this hardware lacks and what could be improved. Maybe you just want to create a nice and <a href="https://iot.stackexchange.com/questions/1085/temperature-sensors-affected-by-rain/1114#1114">waterproof housing</a> and see how it works in practice.</p> <p>You will need several iterations anyway, so start with something oversized (e.g. in terms of RAM or persistent memory) and then strip away unnecessary parts in future iterations. This is much more satisfactory than recognizing that the software you want to use is just 1 KB too large after production. Also, provide good possibilities to debug and evaluate your hardware.</p> <p>Even if you do not need a serial or USB interface for the final application, it speeds up the development a lot. If you are actually building a housing, attach a humidity sensor and monitor it constantly instead of just waiting and checking manually. If you integrate an energy harvester, monitor the energy flows, even if a precise power measurement IC might be oversized for a final application.</p> <p>For the software part, rely on existing components! If you are building a testbed because you like to build hardware and you do not really know what to do with it, publish it! There are many people (see above) that dream to have access to a real-world deployment, so they will happily provide software.</p>

|sensors|wireless|

What should be considered when building a wireless sensor network?

1115

<p>This question originates from <a href="https://iot.stackexchange.com/questions/1085/temperature-sensors-affected-by-rain">a question asking about a specific detail about building wireless sensor networks</a>. While answering the question, I wanted to share some general guidelines for the planning process of a wireless sensor network.</p> <p>So let's consider we want to build a new wireless sensor network deployment. What is the best approach to avoid common pitfalls and mistakes others made before?</p>

2017-02-23T19:57:16.927

<p>Take a look at this <a href="https://github.com/atsign-foundation/sshnoports" rel="nofollow noreferrer">ssh! noports</a> I wrote it for to be able to get to my home office/IoT widgets without having to open up ports to the Interwebs..</p>

|smart-home|networking|

How do I avoid port forwarding when exposing IoT devices to the external Internet?

1117

<p>I received some good answers in the question <a href="https://iot.stackexchange.com/questions/1104/what-do-i-need-to-create-my-own-personal-cloud-for-iot-devices">What do I need to create my own personal cloud for IoT devices?</a> and one of the things that I understood from there is that I need to "expose" my HUB or GATEWAY to the external internet. The proposed solution for that is <strong>port forwarding</strong>.</p> <p><em>I created this as a separate question because it would be difficult to properly to follow-up just with comments on all the answers, someone could get kind of lost. Also, this information may be useful for somebody with a similar question.</em></p> <p>I don't like the idea of having to go to my router configuration and configure the port forwarding because that means that I have to configure a device that in spite of being part of the IoT infrastructure, is not one of "my" devices. It has to be as less disruptive of the already existing home network as possible. Also, I've had instances where I don't know the admin password of a particular router and it has been really difficult to get it.</p> <p>I'm sure that there is a way around that even if that means having a more powerful IoT HUB maybe running Linux, I just don't know what that could be. It is OK to have a bit more complex HUB if that "alternate" way allows avoiding that port forwarding configuration.</p> <p>I say that I'm sure there is a way thinking about how applications like team viewer don't need to configure port forwarding.</p> <p>So the question is, <strong>does anyone know a way of "exposing" an IoT embedded device to the external internet in order to access it from anywhere in the world that does not involve port forwarding?</strong></p>

2017-02-24T08:32:54.473

<p>For simplicity, I'll describe this using a typical smart-home setup as a reference, but nothing here is really fixed by the application. The high level topology is equally suitable for a farm monitoring application covering several kilometres with thousands or sensors, tracking parking spaces in a city, or lighting management in an office building.</p> <p>I'll treat the problem approximately in layers of device hierarchy, which might correspond to increasing complexity of an installation, or pulling in specific use case scenarios. Here is my generalised diagram covering the whole network.</p> <p><a href="https://i.stack.imgur.com/YMRCQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/YMRCQ.png" alt="enter image description here"></a></p> <p><strong>Node level</strong> The individual node in my diagram is a WiFi connected lamp with a local physical override switch. The node often has both sensor and control functions, and a small amount of local compute/storage. Ideally, the node can act autonomously. The node can take control from local switches, directly over the LAN (if it has WiFi/Bluetooth), or from either the local hub or the cloud. A node will frequently maintain a persistent TCP connection with the hub or cloud.</p> <p>One location typically contains several nodes, with different functions, using various connectivity options. A smart-home might collect indoor/outdoor temperature, activity and video data. Remote sensors may use disparate connections to the internet. Nodes typically use <a href="/questions/tagged/microcontrollers" class="post-tag" title="show questions tagged &#39;microcontrollers&#39;" rel="tag">microcontrollers</a>, often at low clock frequencies.</p> <p><strong>Hub Level</strong> In a smart home, there might be several hubs (one for each device vendor), aggregation or hierarchy. The hub can be combined in the router, or stand-alone. The hub doesn't even need to be active in the network (other than to forward packets). However, the hub might be responsible for relaying commands to a node - commands originating from either other locally connected nodes or from a remote server. The hub might implement store-forward of data, compression or filtering of data. Really, the hub is just a facilitator. Today, the hub is the first part of the network that has the ability to provide public DNS, which makes it able to publish network structure information to the full system. As described in <a href="https://iot.stackexchange.com/questions/958/why-do-i-need-hubs-for-some-devices-when-automating-my-home">this question</a> a hub is often necessary to bridge between Wired/WiFi TCP-IP to a low-power radio protocol, such as <a href="/questions/tagged/zigbee" class="post-tag" title="show questions tagged &#39;zigbee&#39;" rel="tag">zigbee</a> or <a href="/questions/tagged/bluetooth-low-energy" class="post-tag" title="show questions tagged &#39;bluetooth-low-energy&#39;" rel="tag">bluetooth-low-energy</a>. Hubs are usually built around <a href="/questions/tagged/microprocessors" class="post-tag" title="show questions tagged &#39;microprocessors&#39;" rel="tag">microprocessors</a>, and are less power-constrained than nodes.</p> <p><strong>Roaming Terminals</strong> Otherwise known as your smartphone. These are often the primary point of user interaction. A simple node can present it's entire user-interface through a smartphone, once the node can establish either a direct or a mediated link with a specific device. Achieving this fundamentally requires a mechanism for establishing trust/ownership/pairing. A terminal can establish if it's own hub is on the local network, if it needs to perform <em>all</em> communication via an external server, or if it is able to lookup the IP address which allows direct routing to it's 'home' hub. The latter scenario usually requires that the router is configured for port forwarding.</p> <p><strong>Cloud service</strong> It is common for the cloud service to perform the majority of the work in the stack, although this is not always necessary (and not all implementations will require any cloud function). The most useful feature that an external (publicly addressed) server can provide is orchestration. Every node and intermediate element of the network is usually able to communicate over a direct channel to this server, and the server can easily pass messages from one device to the others. The server can aggregate data and present visualisations to the user. Based on the user's configuration, it can also forward information to other users (access and heating control can be granted to guests for example, flood/fire/intrusion warnings could use other network options to generate alerts). The cloud is also well placed to take in other data sources, so modifying heating profiles based on forecast and calendar information, or feeding local sensor information into local forecasting models, generating alerts for utility providers and so on.</p>

|networking|system-architecture|topologies|

What is the typical network topology for an IoT network?

1119

<p>I see several questions asking about details of an IoT network, including this one about <a href="https://iot.stackexchange.com/questions/1117/how-do-i-avoid-port-forwarding-when-exposing-iot-devices-to-the-external-interne">port forwarding</a> for example. I think it would be useful to ask about what might be considered the typical baseline architecture for a general-purpose IoT system. </p> <p>We have several questions talking about networking at the sensor side, if <a href="/questions/tagged/mesh-networks" class="post-tag" title="show questions tagged &#39;mesh-networks&#39;" rel="tag">mesh-networks</a> are suitable, etc. For this question, I'm less interested in these - they can be generalised as short-range wireless connections. I'm also not particularly interested in the detail of the local network between nodes, except where the details directly influence the overall network topology.</p> <p>I'm not looking for an exhaustive description, just capturing of the current norm. What <em>general</em> network topology is in typical use today, and provides a good scalable model covering at least these features:</p> <ul> <li>local, networked control</li> <li>remote access</li> <li>sensor nodes in multiple locations</li> <li>data aggregation (for machine learning, etc.)</li> <li>sharing of data (trusted neighbours, etc)</li> <li>resilience to outages (thinking WAN typically)</li> </ul> <p>I'm not looking for inventions here, or answers that go deep into the specific corner cases. I also want to exclude security, except if any aspect of the topology is essential for good security (which I'm assuming is so obvious it doesn't belong on the feature list above)</p>

2017-02-27T09:05:48.303

<h2>Push vs Poll</h2> <p>Your proposed solution of sending frequent AJAX requests sounds a lot like <em>polling</em> - you're sending a request every so often to check if the state has changed. It would make far more sense to <em>push</em> changes to the server when the piezo sensor detects a change.</p> <p>It's the difference between this:</p> <blockquote> <p>Server: <em>Is there someone at the door?</em> Sensor: <strong><em>No</em></strong>.<br> Server: <em>Is there someone at the door?</em> Sensor: <strong><em>No</em></strong>.<br> Server: <em>Is there someone at the door?</em> Sensor: <strong><em>No</em></strong>.<br> <em>... repeat ad infinitum ...</em></p> </blockquote> <p>And this:</p> <blockquote> <p>Sensor: <em>There's someone at the door!</em></p> </blockquote> <p>The first example is polling, and the second is pushing. You can tell which one will have lower power usage, less complex code and reduced network usage.</p> <h2>HTTP or Something Else?</h2> <p>An AJAX request is sent over HTTP, so it's quite heavyweight and requires several <a href="http://www.inetdaemon.com/tutorials/internet/tcp/3-way_handshake.shtml" rel="nofollow noreferrer">TCP handshakes</a> <em>per connection</em> (unless you use <a href="https://en.wikipedia.org/wiki/HTTP_persistent_connection" rel="nofollow noreferrer">Keep-Alive</a>). </p> <p>It may be worth considering alternative protocols such as <a href="https://en.wikipedia.org/wiki/MQTT" rel="nofollow noreferrer">MQTT</a> (there's some good explanation in the question '<a href="https://iot.stackexchange.com/questions/44/when-and-why-to-use-mqtt-protocol">When and why to use MQTT protocol?</a>', which has a very similar problem to yours).</p> <p>A message broker like MQTT might be a little bit more powerful than you really need in your current situation, but one MQTT broker could easily be expanded if you chose to add more devices to your smart home network, whereas your current system of AJAX requests would quickly fall apart. Imagine four or five different devices polling each other; it'd quickly lead to your network becoming overloaded and it would be a massive drain on power usage.</p> <h2>Node and Web Sockets</h2> <p>Using web sockets and Node would solve the issue of using <em>push</em> instead of <em>poll</em>, so it would be a good idea in my opinion. <strong>However</strong>, I suspect polling would work if you really didn't want to learn Node.</p> <p>If you want an <strong>extensible solution</strong> that will work when you expand your smart home, definitely go with pushing - it'll save a lot of trouble and tears. If you just want a quick proof of concept, polling will probably work.</p> <p>My personal advice is that you <strong>should</strong> either learn web sockets or investigate using a message broker like MQTT. You could use a client library like <a href="https://github.com/mgdm/Mosquitto-PHP" rel="nofollow noreferrer">Mosquitto-PHP</a> (with a <a href="http://www.hivemq.com/blog/mqtt-client-library-encyclopedia-mosquitto-php" rel="nofollow noreferrer">guide by HiveMQ</a>) to simplify using MQTT in PHP, or just go with Node and web sockets. I suspect the learning resources for Node and web sockets will be better, but MQTT tends to be favoured for smart home/IoT environments.</p>

|smart-home|raspberry-pi|

Confused about which technology to use in Smart Home System

1130

<p>In my college project (Smart Home System) there's a functionality in which if someone knocks on the door an image has to be displayed on a monitor (in a browser). I am implementing the door knock sensor (Piezo) using an Arduino which somehow has to send commands to the Raspberry Pi to take a photo, which is to be sent to a different computer's browser. There are several other modules like this. Everything is connected to a same WiFi network. </p> <p>Now I can hopefully make it work somehow using PHP and MySQL and several Ajax requests running constantly, but that's probably not a very neat way to do it. I've heard of node.js and web sockets but I am not sure I have time to learn it. (I can if it's absolutely necessary)</p> <p>Anyway can anyone tell me which is the right way to implement this type of system? It would be really helpful.</p>

2017-02-27T15:00:55.507

<p>Probably the biggest M2M protocol other than MQTT is <a href="http://coap.technology/impls.html" rel="nofollow noreferrer">CoAP</a>. While it doesn't natively implement C++ per se, it does implement C and C#, which are not huge leaps if you already have a good understanding of C++.</p> <p>Another well known protocol is <a href="https://www.amqp.org/" rel="nofollow noreferrer">AMQP</a>, for which the <a href="https://github.com/CopernicaMarketingSoftware/AMQP-CPP" rel="nofollow noreferrer">AMQP-CPP library</a> is available, enabling C++ implementation.</p> <p><a href="https://en.wikipedia.org/wiki/WebSocket" rel="nofollow noreferrer">WebSocket</a> also appears to support C++. There are tons of alternatives out there: just pick one and take the leap!</p>

|mqtt|

MQTT alternative (which is also compatible with C++)

1134

<p>I'm quite new to the Internet of Things world and until now I've only heard of MQTT.</p> <p>I want to research some other options apart from MQTT. Until now I've not found much more than Webshpere MQ and ZigBee. I know there must be dozens of other protocols, but I don't know how to select a few suitable ones without spending dozens of hours researching. That's why I reached out to a community that must know a few good ones.</p> <p>What other protocols are there available? </p>

2017-02-27T16:11:42.553

<p>I don't get what you mean by presence, but you can get notifications of door bell button push and / or when motion detection gets triggered.</p> <p>I understood from the specifications that with SmartThings you can switch either one of them on or off and also drive another SmartThings device like a light switch based on the notification.</p> <p>There's more information available in the <a href="https://support.smartthings.com/hc/en-us/articles/214288206-Ring-Doorbell" rel="nofollow noreferrer">SmartThings Documentation</a> on the Ring Doorbell.</p>

|samsung-smartthings|digital-cameras|mobile-applications|

How are cameras utilized in SmartThings?

1137

<p>I'm considering getting an outdoor camera like <a href="http://rads.stackoverflow.com/amzn/click/B01DM6BDA4" rel="noreferrer">Ring</a>. Cameras like Ring are listed in the recommended compatible devices in the SmartThings market. So, I'm curious what sort of automation events are available with cameras like this?</p> <ul> <li>Motion Detection?</li> <li>Presence?</li> <li>Can you control notifications of camera system with other SmartThings events?</li> </ul>

2017-02-28T10:46:18.503

<p>The standard approach is to connect your gateway to a LORAWAN Network server as well described above.</p> <p>If you want to connect the gateway directly to your broker you may use the MQTT forwarding function of your gateway: <a href="https://wiki.dragino.com/index.php?title=MQTT_Forward_Instruction" rel="nofollow noreferrer">MQTT Forward Instruction</a>.</p>

|networking|mqtt|lora|

How can I interface a LoraWan network with MQTT?

1140

<p>I have been working on a project which involves creating a LoraWan network using:</p> <ul> <li>Dragino lg01 as a Gateway.</li> <li>An Arduino Uno and a Dragino Lora shield with a simple LM35 Temperature sensor</li> <li>As for the Server, I have been looking for something open source and compatible with LoraWan, I have found the Wso2 IoT server and I have had some starting it, I think I need to install Apache ActiveMQ JMS Provider with it and I didn't know how.</li> </ul> <p>To send the data from the gateway to the server I am going to use MQTT.</p> <p>As for visualising the data I am going to create an application using AngularJS.</p> <p>So the problem I have had is that I was confused about connecting the node to the Server since I have found two methods (Over-the-Air Activation and Activation by Personalization) and does it affect how the Gateway and the server should be programmed?</p> <p>Also am I going to program the Gateway to send data to the server with MQTT or does all the programming happen in the Node?</p>

2017-02-28T19:47:39.437

<p>Is it possible to have some weight measurement plates at the entrances? With a few weight measurement plates in a line at every gate you can identify movement directions, and by using the average weight of a person, you can approximate number of people on the plate at a time. Indeed, it would be possible to differentiate between an adult and two children, perhaps.</p>

|sensors|

Measure people density in an outdoor area

1146

<p>I'm currently working on a project and I need to measure how many people are in an area without any personal interaction. Basically I need to do this in parks. I don't have lot of budget for each place. All outdoor places. I want to control possible collections of people (fights or unusual collection of people).</p> <p>Some alternatives include:</p> <ul> <li>WIFI Sniffing: Range 30 m.</li> <li>Physical Counter: Few meters</li> <li>Beacons: Range 6 m.</li> </ul>