hybridfree/eevblog-posts huggingface dataset:
SENCOR camera chip identification ES 2L 31Y  - Page 1
Forum section: electronics / beginners

author: misterno
author_rank: Contributor
timestamp: January 14, 2018, 02:17:34 pm
content: Hi all. I have a damaged camera SENCOR that droped into water. I found that the chip ES 2L 31Y was too hot to touch.Is it possible to tell me where i can find it? A circuit diagram also would be nice.TIAhttps://imgur.com/a/GWTgq

author: amyk
author_rank: Super Contributor
timestamp: January 15, 2018, 03:19:27 am
content: You are the second (or perhaps third?) on this site to mention the "ES 2L" QFN32:https://www.eevblog.com/forum/repair/broken-coil-in-hd-mini-camera/According to this post:https://www.eevblog.com/forum/chat/what's-this-please-(component-advice)/msg886985/#msg886985The only constant identifier (the 2L 31Y is a datecode) is "ES" and it could be RT9992ZQW:http://www.szfujiawei.com/aspweb_editor/UploadFile/products/201469151446853.pdf
Sencore F-14 field Effect meter - Page 1
Forum section: electronics / beginners

author: Nesser
author_rank: Newbie
timestamp: March 13, 2017, 11:57:37 pm
content: I have a Sencore F-14 meter that only works on AC. No DC or ohms readings. Any suggestions would be helpful.

author: danadak
author_rank: Super Contributor
timestamp: March 14, 2017, 10:54:40 am
content: Take a look at -http://radiorestorer.com/sencorefe14.PDFIt has schematic and description of circuit operation. Should be relativelystraightforward to trouble shoot.Regards, Dana.

author: Nesser
author_rank: Newbie
timestamp: March 14, 2017, 02:07:43 pm
content: Thanks Dana.
Sencore LC102 Display Problems - Page 1
Forum section: electronics / beginners

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 09, 2015, 12:14:24 pm
content: Just wondering if anyone could help me troubleshoot display issues on a Sencore LC102 Capacitor Tester?The LCD display is exhibiting blurring of characters.I have the operators manual but not the Service manual.Is this a voltage problem?

author: Sencoretech
author_rank: Contributor
timestamp: October 20, 2015, 07:15:49 pm
content: I've never seen one that looks like that. I'm guessing the LCD went bad. It's possible it's a voltage problem but I've worked on a lot of these and it's always been the LCD itself.

author: Johnny10
author_rank: Frequent Contributor
timestamp: October 21, 2015, 01:16:18 pm
content: Thank you!
Send 64 bytes to xbee pro S2b & send to sleep mode - Page 1
Forum section: electronics / beginners

author: embedded.world@aol.com
author_rank: Contributor
timestamp: June 27, 2014, 11:04:18 am
content: Hi,I need to transmit 64 bytes at a time with xbee-pro-s2b. Then send xbee into sleep since this is battery powered application.At receiver end another xbee-pro-2b is connected which is not battery powered. So always on.At transmitter side power is a issue, so I want to send 64 bytes at a time & then set Sleep pin high.xbee pin will tx all the 64 bytes & go to sleep afterwards.Is there any example code for this??
Send and recevie data to and from nodes in LWmesh or WSNDemo - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: August 30, 2016, 11:58:51 am
content: Hi,I have worked with WSNDemo application of LWmesh .I got coordinator and router functioning.Now I am trying to build an application in such a way that when coordinator send the string "request" to router it should reply with the string "reply".In WSNDemo code where can I include the comparison of string and return the response string.Also how can I receive PC rs232 data in coordinator?Are there any function in wsndemo for receiving data from PCKindly suggest a solution
send zigbee module to sleep & wake up on interrupt - Page 1
Forum section: electronics / beginners

author: embedded.world@aol.com
author_rank: Contributor
timestamp: June 13, 2014, 08:09:49 am
content: I am using two zigbee one for tx & other for rx.IU am using xbee pro s2b.1. How to send tx zigbee to sleep by command?2. I want to keep rx zigbee in sleep unless some byte is received. How to do that?

author: lapm
author_rank: Frequent Contributor
timestamp: June 13, 2014, 10:58:39 am
content: Recomend reading datasheet that came with your zigbee modules. Understanding how those works is vital for you to actually use them effectively...Im not even sure if you can sleep receiver at all..
Sending large messages on a CAN bus? - Page 1
Forum section: electronics / beginners

author: e100
author_rank: Frequent Contributor
timestamp: September 27, 2021, 01:34:58 pm
content: Is there something like ISO 15765-2 but not behind a pay wall?https://en.wikipedia.org/wiki/ISO_15765-2"The protocol allows for the transport of messages that exceed the eight byte maximum payload of CAN frames. ISO-TP segments longer messages into multiple frames, adding metadata that allows the interpretation of individual frames and reassembly into a complete message packet by the recipient."Do you think there is enough information on the Wikipedia page to enable me to implement this in code, or is some essential information missing?I'll be writing the sender and receiver so it doesn't have to be a full implementation. I just want to be able to reliably send plain text debug messages.

author: langwadt
author_rank: Super Contributor
timestamp: September 27, 2021, 02:11:23 pm
content: I've implemented it just from the wiki, skipping the flow control

author: JPortici
author_rank: Super Contributor
timestamp: September 27, 2021, 02:37:45 pm
content: iso 15765-2 pdf can be easily found on the netthat said, here is a scan from a BMW vehichle that should be self explanatoryCode:Time Id Sz. D0 D1 D2 D3 D4 D5 D6 D717:53:55:85260x6F108120322F30000000017:53:55:89660x61208F1102A62F300000017:53:55:90560x6F1041230000217:53:55:90560x61208F12164160000000017:53:55:90860x61208F12200000000000017:53:55:91060x61208F12300005400000017:53:55:91260x61208F1247700BA00001A17:53:55:91460x61208F125A9B90133037417:53:55:91660x61208F12601328000800017:53:55:91960x61208F12782FFFFFFFFFFin the ID the lower byte is the source address, D0 is destination address, D1 is Frame Type/Data sizeframe #1 is F1 sending to 12 a single frame of 3 bytes of data (22 F3 00) which is a request for current data at F3 00frame #2 is 12 sending to f1 a first frame for a message of 2A bytes of data and sends the first 5 bytes alongframe #3 is F1 sending to 12 a flow control frame that tells to send successive frames with at least 2ms spacing between each otherremaining frames are the rest of the message requestedin BMWs they decided to use this addressing scheme for diagnostics, but you can choose your own.. if you embed both the source and the destination address in the ID you can gain one more byte per transaction and improve bandwidth
SENDING SENSOR DATA FROM C2000 TO THE CLOUD - Page 1
Forum section: electronics / beginners

author: judith989
author_rank: Newbie
timestamp: March 18, 2021, 08:39:40 am
content: Hello friends. I only recently became acquainted with C2000 launchpads. I have no background knowledge on C++ or TI Launchpads, but I have to make a contribution in a certain project. My task is to send data from C2000 to the cloud. In essence I have to give WiFi abilities to the Launchpad. I intitially started working with CC3100 and although there are limited resources available, i was able to understand that it is incompatible with C2000. Now i am working with CC3220 which is an MCU and WiFi Launchpad. The goal is to send data from C2000 to CC3220 using SPI and send the same data from CC3220 to the local PC using mqtt. Can anyone suggest any links and resources which might be useful in helping me get started?
Sending signal thru power LINE - Page 1
Forum section: electronics / beginners

author: amrat.ch@gmail.com
author_rank: Newbie
timestamp: November 24, 2023, 10:11:12 am
content: I want to send 10Khz low voltage signal thru power LINE then extract the signal at destination (within 100 Meters) How to design the circuit ?Thanks

author: Andy Chee
author_rank: Super Contributor
timestamp: November 24, 2023, 10:16:59 am
content: Here you go:https://community.intel.com/cipcp26785/attachments/cipcp26785/fpga-intellectual-property/8051/1/Transmission%20through%20Powerline.pdf

author: ArdWar
author_rank: Frequent Contributor
timestamp: November 24, 2023, 10:54:19 am
content: Here for a less confusing examplehttps://www.ti.com/lit/pdf/slla590Take it as a pointer on what kind of devices to use and how to interface things. Don't follow the circuit blindly, I think it misses several common safety precautions.Be mindful of your voltage, stay safe.

author: coppercone2
author_rank: Super Contributor
timestamp: November 24, 2023, 11:04:31 am
content: Quote from: ArdWar on November 24, 2023, 10:54:19 amdo not trust dodson with your life!

author: amrat.ch@gmail.com
author_rank: Newbie
timestamp: November 30, 2023, 03:27:37 pm
content: Thanks

author: calzap
author_rank: Frequent Contributor
timestamp: November 30, 2023, 05:33:15 pm
content: If the power line is owned by the utility company, there may be laws or regulations regarding sending signals over it. Check. And if the distance is only 100 m, why not go wireless?Mike in California

author: pickle9000
author_rank: Super Contributor
timestamp: November 30, 2023, 06:10:55 pm
content: google Insteon and or X10
Sense circuit - Page 1
Forum section: electronics / beginners

author: crt
author_rank: Regular Contributor
timestamp: May 01, 2014, 02:47:08 am
content: Hallo everyoneim playing with regulator for motorcycle, i use this schemaits works, C ==> V+ (direct to + battery) and GND to (direct to - battery) to make a better sensebut i need to put some "switch mechanism" to switch them off when engine not runningi measure about 27mA continous when it idlecan you suggest me where should i put a transistor as a switch (+12V as a trigger) ?Sorry for dumb question, i'm newbie about how circuit works

author: Neverther
author_rank: Regular Contributor
timestamp: May 01, 2014, 07:20:21 am
content: Permanent magnet alternator? Or magneto with 3 phases?Why not just use switched 12v for the C input? Or use switched 12v to engage relay for connecting C to battery?

author: crt
author_rank: Regular Contributor
timestamp: May 03, 2014, 12:30:20 pm
content: Permanent Magnet AlternatorI had try with C directly to switched, the higher current, hte more drop i get (with 7Amp i can get almost 0,5VDC difference)I use relay right now, but maybe using a transistor or mosfet will make them more compactany idea ?

author: Neverther
author_rank: Regular Contributor
timestamp: May 03, 2014, 04:09:21 pm
content: I'd rather use relay, dead simple and wont go wrong.You can use some smaller relays (I've used FTR-MYAA012D and theyre rather compact).There is almost no current on the relay so it doesn't need to be big.
Sense resistor offset - Page 1
Forum section: electronics / beginners

author: rulleeeee
author_rank: Newbie
timestamp: September 25, 2018, 06:49:41 pm
content: Hi,I have a question that seems like it would be simple, but that simple solution eludes me. I'm doing some testing with a DAC controlled current limiter in what seems to be the typical way. (See schematic). I'm using the current shunt amplifier to give the sensed voltage a range from 0-4V as current range from 0-10A, and in the actual implementation, the potentiometer is replaced by a 16-Bit DAC. The issue I was having is that while setting low current values, 10-20mA, the zero code offset of the DAC of up to 10mV was causing a positive current offset of 20-30mA.The solution I have been trying so far was to use the additional op amp as a summing amplifier, and bias the sense voltage by ~50mV, and then adjusting the DAC in software to the same offset in order to avoid the troublesome zero scale. Is this a valid approach, or is there a simpler way that I overlooked? The reason I'm asking is that with my attempted solution, I end up with an input voltage bias on the summing amplifier of ~4mV (inv input is 4mA when non-inv input is 0), which sort of takes me back to square 1. Any suggestions would be appreciated.Edit, figured out what was happening, the input is almost rail to rail, so very low values were not well behaved, with a split supply however the issue is resolved.

author: StillTrying
author_rank: Super Contributor
timestamp: September 26, 2018, 02:24:54 pm
content: Could you use the op amp's -INB to sense the resistors 0-200mV directly, and divide the DAC's output to +INB down to 0-200mV.
Sense resistor - Page 1
Forum section: electronics / beginners

author: Hex173t
author_rank: Contributor
timestamp: February 14, 2012, 11:38:24 pm
content: I need a low ohm sense resistor for a battery charger IC (Max713) for charge current feedback. It works out that I need .694 ohm. I don't have this value in a real resistor, I was thinking of using a length of aluminum 24 awg wire instead. I can't think of why this wouldn't work. Is there a good reason not to do this, like it would cause some technical issue? Please keep in mind this is on a bread board and temporary.Thanks in advanceBill

author: BravoV
author_rank: Super Contributor
timestamp: February 14, 2012, 11:56:11 pm
content: Get three resistors which are one 1.2 Ohm and two 3.3 Ohm, put them in parallel and you will get a resistance approx. 0.694 Ohm which is quite close to what you need.

author: grenert
author_rank: Frequent Contributor
timestamp: February 15, 2012, 01:39:48 am
content: At only 0.02567 ohms per foot, you'd need a lot of wire to reach .694 ohms. A lot more than you could deal with on a breadboard (>20 feet).Parallel resistors is a great solution.

author: Rufus
author_rank: Super Contributor
timestamp: February 15, 2012, 03:13:08 am
content: Quote from: Hex173t on February 14, 2012, 11:38:24 pm0R68 is an E6 value and only 2% out.

author: ejeffrey
author_rank: Super Contributor
timestamp: February 15, 2012, 10:20:45 am
content: If you have to use a wire a resistive wire like nichrome is better. It will be shorter and have a lower tempco than aluminum wire.

author: Hex173t
author_rank: Contributor
timestamp: February 15, 2012, 05:39:24 pm
content: Thanks for all the ideas. I didn't mention but I only have (5) 12 ohm and (10) 10 ohm and will give .706, acceptable I think. And I did a quick test of 6 feet of wire and it works out to be .176 ohm, so I need 24 feet of wire which I don't have. Bottom line, whether I go with with nichrome or fixed resistor combos, I alot of wire, alot of resistors or need to do some shopping.I do appreciate the replys, I didn't know about nichrome.Bill

author: robrenz
author_rank: Super Contributor
timestamp: February 15, 2012, 05:44:41 pm
content: I have purchased nichrome from here several times with good success. they have assortments also.http://stores.ebay.com/Wires-Store/_i.html?_fsub=657165
Sense Wires on DC Supplies - Page 1
Forum section: electronics / beginners

author: Bskitter
author_rank: Regular Contributor
timestamp: August 16, 2017, 03:18:35 pm
content: Hello All.I am currently modifiying a Apple G5 Power Supply to an ATX form factor (I all create a separate thread for this when I am finished with the project)I have a quick question about the sense wires on these power supplies. From what I have read the sense wires are basically feedback to the power supply about the voltage on a 5 or 3.3 volt rail. And when the voltage drops the power supply will know to increase the voltage on that specific rail.So on the G5 Power Supply there are 3.3V and 5V sense wires. On the ATX motherboard connector there is a dedicated 3.3v sense wire, but nothing for the 5V sense.I plan to just solder the 5V sense wire to the 5 Volt supply wire just before the ATX connector, is this an acceptable approach ?Byron

author: Bratster
author_rank: Frequent Contributor
timestamp: August 16, 2017, 07:13:38 pm
content: Yes.The 3.3 volt line is done like that, two wires crimped into one pin.Sent from my Nexus 6 using Tapatalk
contact sense using opamp - Page 1
Forum section: electronics / beginners

author: anishkgt
author_rank: Frequent Contributor
timestamp: December 08, 2017, 06:38:04 pm
content: Hi All,Would it possible to use an opamp to sense when two terminals touch each other ?My idea to use it for my spot welder where the contact sense idea would be used to sense if the electrodes makes a firm contact with the spot to be welded. I've just starting learning about op-amps and this seemed like a good start to learn about them with a practical approach.Thanks in advance.

author: anishkgt
author_rank: Frequent Contributor
timestamp: December 08, 2017, 06:55:23 pm
content: Forgot mention that the electrodes are connected to the secondary of a MOT. So i doubt if this would be possible.

author: anishkgt
author_rank: Frequent Contributor
timestamp: December 09, 2017, 07:46:42 am
content: Would this be a correct schematic ? to sense when two electrodes are closed ?

author: anishkgt
author_rank: Frequent Contributor
timestamp: December 09, 2017, 05:25:15 pm
content: at the moment my circuit detects the zero cross on the AC sine wave and triggers two Thyristors in a back-to-back configuration which switches on a MOT(Microwave Oven Transformer) at the peak of the sine, which is the typical way to switch on inductive loads to avoid inrush currents. I also have two taps on the secondary to measure the voltage during a weld to calculate the Weld current. All these are initiated at the press of a button which am hoping to automate when the electrodes touch a conductive material like here, an nickel stripJust not sure how to do this with an opamp or is there a better way to accomplish this task.

author: David Hess
author_rank: Super Contributor
timestamp: December 09, 2017, 05:32:05 pm
content: The low secondary resistance will make this more difficult but not impossible to do at DC by measuring the change in resistance. 10s of microvolts is sufficient with a precision operational amplifier used as a comparator and I once used an OP-90 in an application like this.AC excitation would generate a larger signal do to the secondary inductance and could take advantage of synchronous detection to remove noise yielding a much higher sensitivity. This is a more complicated circuit but would be more reliable.In both cases, the excitation output circuit and operational amplifier input circuit needs to be protected from the open circuit welding voltage and any voltage spikes which is not difficult using series and shunt protection.

author: anishkgt
author_rank: Frequent Contributor
timestamp: December 09, 2017, 05:43:18 pm
content: sounds near to impossible and added cost for components.Thought it could be accomplished with an opamp as a comparator but the second input to the comparator would be hard to get.
sensor and delay timer - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: April 22, 2014, 01:41:33 pm
content: POST REMOVED AT USERS REQUEST

author: Zero999
author_rank: Super Contributor
timestamp: April 22, 2014, 11:08:47 pm
content: Forget the 555 timer, you can use the LM393 as a monostable multivibrator too.

author: Psi
author_rank: Super Contributor
timestamp: April 22, 2014, 11:37:55 pm
content: A mcu is never overkill, it just comes down to price.Is a mcu cheaper or more expensive than using discrete components for the job?

author: Zero999
author_rank: Super Contributor
timestamp: April 23, 2014, 06:03:25 pm
content: Quote from: pereczes on April 22, 2014, 11:25:25 pmIt's on the datasheet.http://www.ti.com.cn/cn/lit/ds/symlink/lm393-n.pdf

author: Zero999
author_rank: Super Contributor
timestamp: April 26, 2014, 11:58:58 pm
content: Yes, you're right, the circuit I was referring to is the one-shot monostable.You need to analyse the circuit to work out the time delay.Firstly, look at the stable state. The input is high and output low. The comparator +input is at half the supply voltage and -input at 0V.When the input goes low, C2 is connected to 0V and the -input is briefly taken one diode drop below 0V, thus making the output go high as the +input is above the -input. The output remains high until C1 charges to half the supply voltage via R1, at which point the voltage across R1 will fall below half the supply voltage. The output will then go low, causing C1 to discharge very quickly through D1.The point in time, at which the voltage across C1 reaches half the supply voltage is a function of the RC time constant R1*C1, which can be calculated using the formulae linked below:http://en.wikipedia.org/wiki/RC_circuit#Time-domain_considerationsThe main issue with this circuit is if the trigger pulse goes high, during the timing cycle, the output will go low and the timer will be reset. This is because C2 will couple the high rising edge so the -input goes above the +input. Fortunately this can be solved by adding a few more components: D3 clips the input signal, ensuring it never rises above half the supply voltage,plus a diode drop, so as long as the input pulse isn't too short, it won't reset the timer, when it returns to positive.

author: Zero999
author_rank: Super Contributor
timestamp: April 27, 2014, 09:17:57 am
content: Quote from: pereczes on April 27, 2014, 01:27:04 amSorry, it was a typo, I meant D2.

author: Zero999
author_rank: Super Contributor
timestamp: April 28, 2014, 10:26:14 pm
content: That would work but a power MOSFET would be a better option.Here's a simpler version of the monostable posted above.
Sensor connection - IEPE accelerometer - Page 1
Forum section: electronics / beginners

author: den
author_rank: Contributor
timestamp: December 28, 2020, 07:25:45 pm
content: Hi everyone,hope someone has experience with IEPE accelerometers. How do I correctly connect it to a measuring device (say, ADC)? Is it normal that signal has a lot of noise (I see +/- 10 g peaks)?Furthermore, my measuring device is switching between several inputs and it has a problem during switching - charge injection. It creates an offset on the signal, and the higher the sampling frequency the higher the offset.These sensors need a conditioning circuit, simple schematic below:https://www.mmf.de/iepe_standard.htmDen

author: den
author_rank: Contributor
timestamp: December 31, 2020, 02:56:56 pm
content: OK, one more try.Maybe I confused people with the last sentence. I have the conditioning circuit of course (otherwise the sensor doesn't work).I have this accelerometer:https://assets.omega.com/pdf/test-and-measurement-equipment/motion-vibration-and-speed/accelerometers/ACC103-series.pdf

author: DH7DN
author_rank: Regular Contributor
timestamp: December 31, 2020, 04:53:02 pm
content: Usually you have to connect the accelerometer to the power supply (or signal conditioner), turn it on and wait few seconds to minutes for signal to settle. Then you're ready to proceed your measurements, depending on the system's time constant. A signal conditioner's constant current line drive (CCLD, also called ICP/IEPE/DeltaTron...) setting of 4 mA is a typical value. Some signal conditioners work as "Uni Gain", a gain factor close to 1.000 or gains in 10 dB steps (1, 3.14, 10, 31.4, 100 etc.).The signal noise of +/- 10 g is not usual. Check the connections and signal conditioner settings (maybe the CCLD is set to 0 mA?). Check the integrity of your measuring chain (accelerometer, cable and signal conditioner) with proper test gear (e. g. an oscilloscope).The offset you're describing during the switching shouldn't occur, unless you're resetting your signal conditioner (e. g. turning off and on) on each measurement.
Sensor studies textbooks - Page 1
Forum section: electronics / beginners

author: DarkEpitaph
author_rank: Newbie
timestamp: April 01, 2019, 01:12:58 pm
content: Hello I've been watching the eevblog for quite sometime now and just wanted to get into the forums. I had been interested in sensor technology(force strain guages, thermocouples, etc) and was wondering if there was any good university textbooks that went into detail on construction, function, and pretty much anything surrounding them. I only have an associates degree in electronics engineering but want to keep learning on my own so any recommendations would be greatly appreciated! Thank you!

author: a59d1
author_rank: Regular Contributor
timestamp: April 01, 2019, 01:26:35 pm
content: Try libgen: gen.lib.rus.ec.

author: soldar
author_rank: Super Contributor
timestamp: April 01, 2019, 07:33:48 pm
content: This is an area of my interest and it is a very good question. I guess you can find some general introductory texts but I am thinking that different types of sensors are so specialized and use so different technologies that any one type can be an entire world.Have a look at this:https://en.wikipedia.org/wiki/Mass_flow_meter

author: packetbob
author_rank: Contributor
timestamp: April 01, 2019, 10:22:41 pm
content: "Lessons in Industrial Instrumentation" by Tony R. Kuphaldt is a great public domain textbook that covers all aspects of sensors used in instrumentation:https://www.ibiblio.org/kuphaldt/socratic/sinst/book/liii_2v32.pdfThe main web page has a lot of other info related to instrumentation:https://www.ibiblio.org/kuphaldt/socratic/sinst/

author: DarkEpitaph
author_rank: Newbie
timestamp: April 03, 2019, 10:34:06 am
content: Thank you so much! "Lessons in Industrial Instrumentation" seems like a really good read with a wide range of topics! Should keep me busy for a while!
Sensors in voltage divider configuration - Page 1
Forum section: electronics / beginners

author: Aldobrandi
author_rank: Regular Contributor
timestamp: April 19, 2012, 03:40:30 pm
content: I am building a simple thermostat circuit using a thermistor and to get started I've looked at plenty of exemples. I understand how they work (most of them using an op-amp in Shmitt Trigger configuration) but I'm curious as to why the sensor (the thermistor in my case) is always used in a voltage divider configuration: why can't you simply use the thermistor on its own on the op-amp inverting input ? Here's one of the many circuits I've looked at and which uses this voltage divider configuration :http://pcbheaven.com/circuitpages/Simple_Reliable_Thermostat/Thanks a lot !

author: Unknown
author_rank: Unknown
timestamp: April 19, 2012, 04:12:24 pm
content: Thermistors have resistance. Op-amps expect a voltage at their inputs. How do you convert resistance to voltage?

author: Aldobrandi
author_rank: Regular Contributor
timestamp: April 19, 2012, 08:28:34 pm
content: Thanks alm for your quick reply.Please forgive me if I am being dense, but I think I still need clarification on this topic and to be sure I am understood I have thrown together a partial circuit (I know this is not a working circuit, I've only included the parts relevant to my question).Since the thermistor's resistance is proportional (inversely in the case of a NTC) to temperature, would the voltage dropped across R1 decrease as the temperature increases (because the resistance will decrease as the temperature increases) ?Please explain to me like I'm 5 why my circuit wouldn't workThanks for your patience and your help !

author: Aldobrandi
author_rank: Regular Contributor
timestamp: April 19, 2012, 09:01:34 pm
content: To follow up I decided to draw an equivalent circuit with a new resistor, R0, forming a voltage divider with the thermistor, but where R0's value is infinitely small. Would such a circuit work ?

author: MikeK
author_rank: Super Contributor
timestamp: April 19, 2012, 09:21:15 pm
content: Your first circuit won't work, because the op-amp input is essentially tied to 12V. And then dangerous things happen when the sensor resistance goes to zero...You're shorting the supply voltage to ground.A voltage dividier is a basic ciruit whereby two resistors produce a fraction of the input voltage. And that's what your second circuit is doing. As R1 goes up the voltage at the op-amp input goes down. And as R1 goes down the voltage at the op-amp input goes up.Vout = Vin x (R0/(R0+R1))

author: Aldobrandi
author_rank: Regular Contributor
timestamp: April 19, 2012, 09:32:51 pm
content: Thank you so much MikeK for your detailed explanation. As we say in French, I am the kind of person who understands quickly as long as you explain slowly! This is much appreciated.

author: Jeff1946
author_rank: Regular Contributor
timestamp: April 20, 2012, 12:57:57 am
content: You should put a resistor in series with the thermistor. It will work best if the resistor has the same resistance as the thermistor at the control temperature. Proof of this is left to the reader.
Sensors, probes, cables, etc, for oscilloscope for automotive diagnosis - Page 1
Forum section: electronics / beginners

author: danbuff
author_rank: Contributor
timestamp: December 31, 2016, 02:27:45 am
content: Hello all,First off, thanks for a fantastic group of knowledgeable helpful folks.So much to learn..I am going to be buying a DSO for general electronics usage, but also automotive diagnosis.Scope likely DS1054ZSuggestions for probes, cables, sensors for the scope? Maybe home-brew..I have a clamp on current probe..Wondering what type of sensors/probes for auto diagnostics.. Secondary ignition, etc.Also, place to purchase DS1054Z ?Thanks so much!!DanRetired, tinkerer, ham operator

author: Andreas
author_rank: Super Contributor
timestamp: December 31, 2016, 07:17:39 pm
content: Hello,what about this:https://www.picoauto.com/productsWith best regardsAndreas

author: danbuff
author_rank: Contributor
timestamp: December 31, 2016, 08:39:52 pm
content: Thanks Andreas.. Those are the types...Perhaps I can find some DIY versions too..Gives me good ideas!!Dan

author: danbuff
author_rank: Contributor
timestamp: January 01, 2017, 12:13:25 am
content: Here's a DIY example of a coil over plug sensor:http://www.ford-trucks.com/forums/1159255-poor-mans-cop-scope-probe.htmlI know commercial ones are available, but might be fun to experiment with a roll your own..Commercial one:https://www.otctools.com/products/scope-universal-cop-probeDan

author: Mickster
author_rank: Contributor
timestamp: January 01, 2017, 12:38:57 am
content: The Pico First Look Sensor (Pressure transducer) is quite handy, albeit pricey. It is not a pressure sensor, it only measureschangesin pressure, but this is useful for checking for low compression/leaky valves etc, without pulling spark plugs and carrying out a regular compression test. Attach it to a vacuum take-off on the intake manifold or stick it up the tail pipe, trigger off cylinder 1 and use the chart to line up the defective cylinder(s) to your trigger point.A great place for automotive info is here:http://www.autonerdz.com/cgi/yabb2/YaBB.plI have no affiliation with either Picotech, or Autonerdz.Regards.

author: danbuff
author_rank: Contributor
timestamp: January 01, 2017, 01:51:33 am
content: Thanks for the link! I wasnt aware of that site.I agree, Pico pressure transducer is fine piece.. But pricey for non-professional need.I am finding youtube videos on DIY pressure transducers for scope usage.. Cool stuff.Dan

author: danbuff
author_rank: Contributor
timestamp: January 01, 2017, 05:52:18 pm
content: Pressure pulse sensor would be another item to use.Here is a link to a DIY unit:http://www.locostbuilders.co.uk/forum/47/viewthread.php?tid=200739commercial version:http://autoditex.com/pressure-pulse-sensor-63.htmlDan
sensors watertight - Page 1
Forum section: electronics / beginners

author: salviador
author_rank: Regular Contributor
timestamp: August 18, 2015, 08:44:14 am
content: Hi, I have a waterproof box "1555BGY", I want to insert the sensors such as temperature , humidity and also pressure.I want to measure atmospheric conditions outside.The waterproof box affects the poor measure sensors?

author: jpenn
author_rank: Contributor
timestamp: August 18, 2015, 03:04:39 pm
content: You can't do that! Humidity sensors need to be exposed to the air as do the barometric sensors. The best bet for this situation is to mount it out of the direct sun an put a splash cover over the unit. Make sure its open on the bottom to drain excess moisture.
SENT Shaped waveform and dual stage RC filter - Page 1
Forum section: electronics / beginners

author: pman92
author_rank: Contributor
timestamp: August 09, 2023, 09:43:23 am
content: Hey guys,I'm no electrical engineer, but I'm working on a hobbiest project using a SENT J2716 transmitter / receiver in an automotive environment (essentially intercepting some data, modifying it and retransmitting it). I'm using a dsPIC33EV microcontroller which includes hardware that takes care of the signal timing calculations/decoding for me (for both transmit and receive).I'm trying to work out the rest of the hardware side of things. I want to do the best job I can of it. I've learnt a lot already from this project and I think it could be a great opportunity to improve my hardware skills as well. I have a copy of the SAE J2716 documentation which provides this circuit:The receiver portion is actually the recommended implementation. The transmitter section is example only and should not be taken as direct implementation requirement. These are the questions I have:1. Selection of Rf and Cf for the second stage receiver filter.The documentation specifies:- tau1 (Rtau1, Ctau1) time constant = 0.74 to 1.73 uS- tau2 (determined by Rf and Cf) = 0.6 to 1.4uS- Rtau1 = 560 ohms +/-20%- Ctau1 = 2.2nF +/- 30%- Rv is not required in my application (its to create a voltage divider to reduce signal voltage, not required for the dsPIC33EV).- Rf minimum = 4kohm (chosen so 0.1mA sourcing capability of transmitter cannot be exceeded).When selecting Rf and Cf, do I need to take Rtau1 or Ctau1 into account? Or is it as simple as Rf x Cf like a single stage filter? Or do Rtau1 and Rf add together first?2. The specified parasitic receiver input capacitance (Cinput) is specified as 0.1nF. I was planning to include a TVS diode for protection, but they seem to use all or more of that maximum capacitance specification by themselves. Is there an alternative method for overvoltage protection that doesn't have much capacitance?3. Transmitter circuit. I planned to first use an opamp as a unity gain filter (voltage follower) on the transmitter pin from my dsPIC33EV. The SENT J2716 documentation states that a "shaped waveform" is expected to be driven by the transmitter to meet EMC requirements (which it doesn't actually specify, it says should be specified by the OEM). It provides maximum rise and fall times, as well as min/max low and high state voltages. Is implementing an RC filter after the voltage follower (R01, C02 in the circuit) going to be the best way, or is there a more elegant way of creating the shaped waveform?Thanks in advance
Separate noise from STEP-UP CONVERTER - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: February 04, 2015, 05:20:55 am
content: 1. I have to make 5V from single Li-ion cell, whose voltage can vary from 2.7V to 4.2V.My current need at 5V is 400mA (max)2. I have selected TI's TPS81256 for this application. This is meant for my application.Just one output capacitor required, & thats it.3. TPS81256 works at 4Mhz. So it generate noise & it can effect my circuit as it has lots of analog cicuit.4. What value of decoupling capacitor I should use to filter this high frequency noise?5. Xc = 1/2*pi*f*cSo I need Xc to be infinite for low freq & zero for high freq (ideally for bypass caps)So I think using 4.7uF, 10uF & 0.1uF in parallel will be sufficient?
Separating power busses into domains on a backplane - Page 1
Forum section: electronics / beginners

author: matseng
author_rank: Frequent Contributor
timestamp: July 10, 2018, 11:57:12 am
content: I guess that this is right up T3sl4co1l's alley... A while back I read this interesting post about transmission lines and termination for improving signal integrity.vagrearg.org/content/translineThe part about separating the power domains of the sender and receiver parts of a transmission line was new to me - but how do I select chokes and caps for this? Should one one use both bypass and bulk caps at both the top and bottom parts of the choke? And what about the choke itself - could any off-the-shelf parts be used for a board that pulls 2-3 amps? Or maybe it would be easier to just wrap a dozen of turns of magnet wires around a ferrite toroid code (which I absolutely have no idea of how to select) and hope for the best - as long as one doesn't make things worse?
Seperate switched AC plus DC signal  - Page 1
Forum section: electronics / beginners

author: Chrische
author_rank: Newbie
timestamp: September 15, 2016, 06:50:10 pm
content: Hey everyone,I currently working on a project that involves sensing a low voltage ac signal that is superimposed on a large dc offset.The problem is that this ac signal is switched.So whenever i try to ac couple it, in order to remove the undesired dc component from the signal, i get the problem thatcan be seen from the picture that i attached.Obviously it is the time constant from the coupling capacitor and shunt impedance that is responsible for this kind of response.I cannot really find a solution to this problem.So i hope you have any ideas how to solve this problem. Maybe even a circuit example, but any hint is very much appreciated!

author: Signal32
author_rank: Frequent Contributor
timestamp: September 15, 2016, 07:36:42 pm
content: You need to provide more context in order for us to figure out what solutions would work. Such as:What are you trying to sense it with ?Why are you sensing it - what are you trying to do ?An easy generic solution is use DC coupling and don't use ground as the sensing point, but generate another voltage equal to the offset that you have and use that as ground.

author: PartialDischarge
author_rank: Super Contributor
timestamp: September 15, 2016, 08:05:24 pm
content: As signal32 pointed the context is important, that way you can tailor a proper solution.However dont expect a system that will give you the ac signal instantly after you apply an ac+dc input. Even if you were to convert the signal into digital with a fast ADC and come up with a software algorithm to separate both, il'll take a few iterations for it to separate the DC given that you properly define the min and max components of the spectrum of the AC signal

author: Chrische
author_rank: Newbie
timestamp: September 15, 2016, 08:21:29 pm
content: Ok, so almost immediately after i posted the original post i got an idea. It seems to solve the problem but i don't really like the circuit because i think there might just be a simpler solution.You can have a good look at the pictures i attached below i think they should explain it a bit better.I attached also a LTspice model of the circuit so it might become a little more appeared what I'm trying to do.
SEPIC controller for Acid-Lead battery - Page 1
Forum section: electronics / beginners

author: Darlington
author_rank: Contributor
timestamp: September 16, 2024, 09:57:05 am
content: Hello everyone,I am looking for a SEPIC integrated circuit to recharge a lead acid battery, but I have not found anything on the market. However, I found the LT1512 integrated circuit, but it is expensive for me and not available.I need that from a 12-volt input I can charge the battery at 14.4 volts and then stabilize the output at 12volts again.Does anyone know of an equivalent, low cost component?
SEPIC voltage regulator, one or two inductors? - Page 1
Forum section: electronics / beginners

author: alexg
author_rank: Regular Contributor
timestamp: October 25, 2016, 11:35:39 pm
content: Hi All, I am going to try to build SEPIC voltage regulator, did not chose which particular chip I will use but I noticed that on some of them inductors marked with small dot on one end (see attached illustration), and when I try to find such inductor on digikey it seems that only type that have such marking is where two coils are wrapped around the same core or something, can I simply use two separate independent inductors?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 26, 2016, 01:01:20 am
content: Two winding coupled inductor. Coupled inductor gives better performance (lower input ripple). The datasheet will indicate which pins are dotted.It will still work with uncoupled (discrete) inductors.Tim

author: alexg
author_rank: Regular Contributor
timestamp: October 27, 2016, 02:35:22 pm
content: Great, thanks, I will build both and compare performance, but its good to know that two separate inductors can be used, I can keep things "lower profile" on the PCB this way.

author: chris_leyson
author_rank: Super Contributor
timestamp: October 27, 2016, 03:35:50 pm
content: Strictly speaking if you couple the two inductors it's no longer a Sepic converter. In the coupled inductor version the ripple currents increase and the closed loop performance changes. Seehttp://www.switchingpowermagazine.com/downloads/Sepic%20Analysis.pdffor example plus a lot more athttp://www.ridleyengineering.com.There are a few papers out there on the internet stating that a Sepic benefits from a fair amount of leakage inductance if you use coupled inductors. Also un-coupled and coupled versions of the Cuk converter are completely different.

author: rfbroadband
author_rank: Unknown
timestamp: October 29, 2016, 04:09:34 am
content: use one coupled inductor. Make sure you select one that supports the peak current of your design. Make sure you understand the hot loops of the SEPIC architecture to minimize ripple. Linear Tech has a few excellent app notes on layout considerations for different switching architectures. Use a 4 layer board to minimize spacing to next gnd layer in your PCB stack up (even though a 2 layer board would be sufficient from a routing point of view). The 1.6mm distance to the second GND layer will hurt you for ripple in a 2 layer design.I recently designed one using the LT3758 and works great, but you have to take the layout extremely seriously. Make sure you design your board so you can easily tune the frequency response of the control loop. No matter what you simulate, you will need to tune the loop for stable operation.
Serial between two 'systems' (embarrassing question) - Page 1
Forum section: electronics / beginners

author: alexanderbrevig
author_rank: Frequent Contributor
timestamp: April 04, 2015, 10:55:22 am
content: Hi again. For some reason I cant make my head up if I'm thinking straight. So to illustrate, here's a schematic:I'm not sure if sharing V+ is OK. If not, could I share ground to make each system recognize HIGH sent from the other over a UART?I've tried to google and search the forum but I don't have sufficient terminology or intuition for what search terms would be best. Sorry.I'd appreciate any and all input.Kind regards

author: digsys
author_rank: Unknown
timestamp: April 04, 2015, 11:05:30 am
content: With RS232, you do need to reference the 0Vs, and be SURE they really are at 0V relative to each other. RS485, gives you some latitude if youcan't guarantee they can be tied. As for V+, you only need to share it, if the remote connection has no supply, or you prefer to supply it fromthe host (or vice-versa). So you only need 3 connections.

author: MatthewEveritt
author_rank: Unknown
timestamp: April 04, 2015, 11:08:28 am
content: Sharing V+ is generally a bad plan, whereas sharing ground is generally a good plan. Putting different power supplies in parallel is a recipe for damage.In this case, just cut the V+ and let the common ground provide a reference.Typically serial devices recognise high and low signals by comparing them to their power supply, so (very roughly) anything less than half Vcc is a 0, anything more than that is 1. There's generally enough 'wiggle room' in that to allow devices with separate but similar power supplies to understand each other. If not you need some active level translation.

author: alexanderbrevig
author_rank: Frequent Contributor
timestamp: April 04, 2015, 11:15:32 am
content: Thanks guys! Three wires it is. It was what I thought as well before I started pondering about it. I've shared both before but as you pointed out I only had one power source then.I am sure GND will be the same for both systems so should be fine.Thank you both
Serial comms - actual data transmitted - Page 1
Forum section: electronics / beginners

author: swmcl
author_rank: Contributor
timestamp: April 12, 2017, 09:37:13 am
content: Hi,I have taken a digital photo of my DSO screen of a serial data capture at the output of a USB to serial comverter.Both chips (the Microchip MCP2200 and the Silicon Labs CP2102) show exactly the same data.The ASCII for 'b' is 98 decimal, 62 hex.In binary it is 0110 0010 (MSB --> LSB)To my way of thinking I have a binary stream something like this at the output:0 0100 0110 1010 1100 0010 0101 0000 1111The first '0' is a start bit and the communications ends with the line in a high state as seen with the '1's at the end. The stop bit is the fourth '1'.The actual bit sequence for the letter 'b' is seen in the first 8 bits I believe and is in 'little endian' where the least significant bit is transmitted first. ie it is back to front to the 62hex.The port setup was 8-N-1. That's 8 data bits, no parity and 1 stop bit.The question is, "What are the other bits??"Please see my photo of the scope.Cheers,Steve

author: bktemp
author_rank: Super Contributor
timestamp: April 12, 2017, 09:58:15 am
content: Looks like CR + LF.For every byte there is a start and a stop bit, so the correct decoding should look like this:0 0100 0110 1 620 1011 0000 1 0D0 0101 0000 1 0A

author: macboy
author_rank: Super Contributor
timestamp: April 12, 2017, 03:37:44 pm
content: +1 bktemp is absolutely correct.When sending 8 bit data words, there are 10 bit periods per data word transmitted. The start and stop bits are sent for every data word (byte).Little-/big-endian does not refer to bit order, but to byte order within multi-byte words. You are however correct that UART data is sent LSb first (least significant bit first). BTW, always use a lowercase b" for bit, uc "B" for Byte. LSB therefore refers to least significant byte (not bit) which you might refer to when talking endianess. Use the same convention for data rates: Mbps is millions of bits per second, MBps is millions of bytes per second.

author: swmcl
author_rank: Contributor
timestamp: April 12, 2017, 08:45:16 pm
content: Ahhh!Now I feel a little bit silly and a lot bit (small 'b') thankful for your replies!I can rest a little knowing that the rest of the data is explained. I didn't think of the CR LF.Thanks guys.
Serial communication for ROV. - Page 1
Forum section: electronics / beginners

author: Edvin gjerde
author_rank: Newbie
timestamp: May 11, 2022, 06:56:31 pm
content: I am working on a ROV (remote operated vehicle) and I need to make two arduino cards communicate with Rx and Tx pins. I have test many different codes but nowon have worked. The problem is not the connection between the cards I knows that Rx-> Tx & Tx-> Rx & gind<->gind. You knows any code I can try next?It is one arduino uno and one arduino mega thats is going to communicate. The konektsons between the board were whid jumperlinks.senderchar str;void setup() {Serial.begin(9600);}void loop() {int value=1234;itoa(value, str, 10);Serial.write(str, 4);}resiverchar str;void setup() {Serial.begin(9600);Serial1.begin(9600);}void loop() {int i=0;if (Serial1.available()) {delay(100);while(Serial1.available() && i<4) {str[i++] = Serial1.read();}str[i++]='\0';}if(i>0) {Serial.println(str,4);}}excuse my english

author: Manul
author_rank: Super Contributor
timestamp: May 11, 2022, 07:34:42 pm
content: What is the length of the cable between arduino boards? Do you know that on UNO boards UART pins are also used for virtual serial port while connected on USB, so it will not work while on USB (as far as I remember, I'm not an arduino specialist)?It would be useful if you could post code which you tried and it was not working. It is hard to say what you should try next, when we don't know what you have tried already. Keep in mind, that while there are tons of badly witten arduino code online, the fact that you have tried many and none worked probably means that the problem is either not the code or there is a need to configure the code in some way for your particular case.

author: SmallCog
author_rank: Frequent Contributor
timestamp: May 11, 2022, 11:18:31 pm
content: Consider using RS485 if there'll be any length to the cable - I imagine this is likely with an ROV