hybridfree/eevblog-posts huggingface dataset:
Sun PEX-737-30 server power supply  - Page 1
Forum section: electronics / projects

author: Gordon
author_rank: Newbie
timestamp: May 07, 2016, 11:04:48 pm
content: Hi guys, I have a couple of Sun PEX-737-30 server power supplies following a server upgrade at work. I can get them to power on by shorting the blue-green wires, now I'd like to increase the working voltage from 12v to 13.8v. Does anyone have circuit information or experience with this unit? Any help or pointers would be greatly appreciated.Thanks - Gordon
Sunday Heads with virtual faces for every robot out there - Page 1
Forum section: electronics / projects

author: salihkanber
author_rank: Regular Contributor
timestamp: June 19, 2023, 09:35:54 am
content: Nowadays humanoids with human like heads is a hot topic. Well.. How about developing a robot head with a virtual face on it? That is not new I know, yet I believe, the efforts towards this will be effective; I see the light at the end of the tunnel, and I am confident that we have valuable additions to contribute to this matter...So here we started with a 4DOF platform design, will put the head on it with a screen and a Rasp Pi4 inside..The mechanism in the photo doesn't resemble anything at the moment, but it is a promising start for the project and will evolve over time.Any comments & feedback will be appreciated, thanks.

author: salihkanber
author_rank: Regular Contributor
timestamp: June 26, 2023, 12:39:09 pm
content: Still couldnt create a rigid 3DOF platform for the Sunday Heads and after the efforts of my colleague, the ball is in my court again.The initial structure couldnt stop the platform from yawing and adding an additional mechanism in the middle makes the whole thing unnecesarily complicated.Instead I think reorientation of servos towards the center and strenghtening their rotational axis will solve the problem.
Sunlight readable LC-display for raspberry pi - Page 1
Forum section: electronics / projects

author: m98
author_rank: Frequent Contributor
timestamp: April 14, 2018, 01:52:53 am
content: Hi,since last year I'm working on a modular glider avionics suite. At first, I planned to only provide sensors and processing and then transmit the data to a mobile device for display, however, after seeing projects like OpenVario, I now also want to design my own MFD. I want to use a Raspberry Pi Compute module 3 as the base since its cheap, well documented and has the perfect form factor.Now comes the issue, I need a screen that is readable under direct sunlight, so it should either be transflective or have a bright backlight (1000 cd/m² +). Size should be around 7" to 10" and the resolution should be higher than WVGA. Since I don't want to use a chinesium adapter board or try to fail spinning something similar myself, the panel should have a DSI or parallel RGB interface that is compatible to the Raspberry Pi without too much tweaking. Spend the last few hours searching for an off-the-shelf component meeting those requirements, didn't get too successful. Only found ones with LVDS interface or RGB interface but with WVGA resolution. So I hope someone might have their google-fu strong today, or maybe even used a similar component in their project.

author: ebastler
author_rank: Super Contributor
timestamp: April 14, 2018, 06:24:13 am
content: Just Googling, no first-hand experience:Transflective screens with sizes in the 7" to 10" range seem to be available; but you would probably be looking at a separate display driver board. (Which you can probably source from the LCD supplier, but would have to integrate mechanically.)https://www.alibaba.com/product-detail/7-0-transflective-color-tft-LCD_60618712489.htmlhttps://www.alibaba.com/product-detail/Touch-10-inch-TFT-screen-skd_60433786815.htmlIf you want an integrated solution, little monitors which claim to be transflective are available as car accessories. HDMI input seems to be common, and they come more or less nicely packaged. The ones I found at first glance are painfully expensive however, $450 and up. There must be better offers?http://www.cartft.com/catalog/il/2021http://www.carlcd.net/.sc/ms/dd/ee/134

author: MolsonB
author_rank: Newbie
timestamp: February 19, 2019, 03:55:14 am
content: Did you end up finding one that worked?

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 19, 2019, 04:19:52 pm
content: You could take a look there too:http://store.lcdparts.net/search.asp?keyword=sunlight&search=searchSuch as:http://store.lcdparts.net/104-2000-nits-Sunlight-Readable-MS104RSBLCD2000_p_7396.htmlNot cheap.Adapter boards are available (HDMI). Forget about DSI on an RPi with just a random panel. Really.

author: engineer_in_shorts
author_rank: Regular Contributor
timestamp: October 01, 2020, 11:20:06 am
content: Hi,Did you find any transflective LCD screens that fit the project? I have very similar requirements and a bit unsure of where to look.
Sunlight viewable LCD display? - Page 1
Forum section: electronics / projects

author: Renate
author_rank: Super Contributor
timestamp: January 28, 2020, 10:34:10 pm
content: I was wondering if anyone had experience with retrofitting a normal 20-odd inch computer LCD display with an eye-scorching LED backlight.I was trying to use a normal 20-odd inch LCD for a public display.Even in the shade a stock LCD isn't that visible.I think the one that I'd try is using CCFLs right now.The uniformity of ilumination wouldn't be that critical.I've had LCDs apart before, checking the image when the backlight died.I've thought about making it open back to directly use sunlight, but that gets messy.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 28, 2020, 10:58:22 pm
content: Not done that... But I've bought sunlight readable panels before.As a rough figure, I'd say 1000 cd/m2 is the very minimum to get something usable.

author: Renate
author_rank: Super Contributor
timestamp: January 28, 2020, 11:20:07 pm
content: Quote from: SiliconWizard on January 28, 2020, 10:58:22 pmMmm, I'll bet those are more expensive than the displays that I pick up at a charity shop.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 28, 2020, 11:36:03 pm
content: Quote from: Renate on January 28, 2020, 11:20:07 pmDefinitely.The only reasonably priced ones I bought were 7", but still not cheap. The larger ones were very expensive.
Super cheap vibration motor - Page 1
Forum section: electronics / projects

author: Phil1977
author_rank: Frequent Contributor
timestamp: July 30, 2025, 10:35:29 am
content: Hi,I assumed that these vibration motors would be magnetic exciters and could be misused as a super cheap vibration sensor - unfortunately this does not work out, these things are small unbalanced brushed DC motors!https://de.aliexpress.com/item/1005009267048597.htmlJust for the curious people who want to know how much mini-technology can be packed into a €0,20-device I´ve openend one up and uploaded the pics:
Super Cool Magic Eye Radio Project - Page 1
Forum section: electronics / projects

author: Electro Fan
author_rank: Super Contributor
timestamp: January 01, 2025, 08:09:12 am
content: This likely belongs here in the project forum but it could be in several forums including RF/Radio, microcontrollers, circuit CAD, 3D printing, and probably more. Beautiful project documentation. Author has other very interesting projects/product reviews/articles too.https://retronics.no/2024/08/29/diy-digital-6u5-magic-eye-replacement/

author: Dave Wise
author_rank: Regular Contributor
timestamp: January 04, 2025, 06:42:47 pm
content: That. Is. Awesome. Bookmarked.It will work in most radios. Not every application will be a drop-in; I have an ESI 250DA Impedance Bridge which uses the triode section as a detector, and the tube displays the instantaneous value not average.
super lightweight counter-rotating mars helicopter. - Page 1
Forum section: electronics / projects

author: cdev
author_rank: Super Contributor
timestamp: February 28, 2021, 07:52:43 pm
content: Powered flight on other worlds. That's quite a first.

author: MikeK
author_rank: Super Contributor
timestamp: February 28, 2021, 08:11:45 pm
content: That video is from like a year ago. Just what kind of nerd are you? lol jkYeah, it's a first. And we'll see in a few months if it actually works.

author: cdev
author_rank: Super Contributor
timestamp: March 02, 2021, 02:44:23 am
content: Leonardo Da Vinci's idea.

author: cdev
author_rank: Super Contributor
timestamp: March 02, 2021, 02:46:54 am
content: The videographer looks familiar for some reason. I feel like I know him from somewhere.
Super Small 110/250v to 5v ACDC - Page 1
Forum section: electronics / projects

author: CharlesSpong
author_rank: Contributor
timestamp: January 20, 2017, 09:12:08 pm
content: I am looking for a super small 110/250v to 5v ACDC converter that is preferably quite cheap. It needs to be able to supply AT LEAST 1A 5V. If anyone know of one they think will meet my requirements please suggest it.

author: mmagin
author_rank: Frequent Contributor
timestamp: January 20, 2017, 09:51:31 pm
content: Just plug it into a parametric search like digikey's or similar. On the cheap end, I see:http://www.digikey.com/short/3rw1zcHowever if you want something fully packaged, I don't think you'll do better than buying a name-brand USB charger (Apple, etc.)

author: Fungus
author_rank: Super Contributor
timestamp: January 20, 2017, 10:41:00 pm
content: http://www.ebay.com/itm/332007274704(randomly chosen seller)

author: cowana
author_rank: Frequent Contributor
timestamp: January 20, 2017, 10:54:29 pm
content: Quote from: Fungus on January 20, 2017, 10:41:00 pmFrom the cut-off wires, those look like modules salvaged from the recycling - I'd be slightly wary of random mains power supplies that I didn't know the safety certs and history of!

author: Seekonk
author_rank: Super Contributor
timestamp: January 20, 2017, 11:27:48 pm
content: That is like every cell phone charger. There is a thrift store I go to that sells them for 29 cents each. I always buy about 10 at a time, they think I'm nuts. I use them for solar applications. Most work fine on a 60V buss.

author: SeanB
author_rank: Super Contributor
timestamp: January 21, 2017, 07:13:53 pm
content: Quote from: cowana on January 20, 2017, 10:54:29 pmSo that is where all those Samsung Note chargers landed up. They, unlike the phone, tend not to explode in use, until at least after the warranty period.

author: IanB
author_rank: Super Contributor
timestamp: January 21, 2017, 07:20:57 pm
content: Quote from: CharlesSpong on January 20, 2017, 09:12:08 pmThe Apple "cube" charger sold in the USA is about as small as they come. It is also safe, reliable and meets its specs.

author: CharlesSpong
author_rank: Contributor
timestamp: January 21, 2017, 08:27:10 pm
content: Thanks for your helpful comments however I was obviously not clear, i am looking for a PCB mount converter module.

author: Wilksey
author_rank: Super Contributor
timestamp: January 21, 2017, 10:58:05 pm
content: Here is what i've used in the past:http://uk.farnell.com/vigortronix/vtx-214-005-105/ac-dc-conv-fixed-1-o-p-5w-5v/dp/2401040Any good for you?

author: CharlesSpong
author_rank: Contributor
timestamp: January 22, 2017, 07:12:00 am
content: Quote from: Wilksey on January 21, 2017, 10:58:05 pmLooks great

author: amyk
author_rank: Super Contributor
timestamp: January 22, 2017, 07:48:45 am
content: You haven't told us if isolation is required or not. The choices are more plentiful if you don't.
Super-small FPV quadrotor  - Page 1
Forum section: electronics / projects

author: RCMR
author_rank: Frequent Contributor
timestamp: September 08, 2012, 09:30:52 pm
content: Most people have seen quadrotors these days. Four electric motors attached to four props, some gyro-stabilization and an RC set mean you can hover about and have a ball. Dave is even contemplating one for getting some cool canyon videos.You can spend a bit of money and an awful lot of time farting around building your own quad and break a lot of props during the learning process -- but these days you can also spend about $100 and buy a tiny (100mm between motor centres, 32g) "off the shelf" machine like the Walkera Ladybird QR.I bought two of these little quads a few months ago and have been having a ball. Although they're *tiny* and use a single 260mAH lithium cell for power, these birds can actually carry an HD keychain camera (weighing 17g) to get some impressive aerial video.However, I wanted to do live video and fly FPV (first-person view) so I fitted a sub-2g video camera and a 200mW 5.8GHz video transmitter module. A bit of bodging was needed to add a regulator for the video transmitter module but it all seems to work pretty well.Here's the build-video. Some "pilot's eye" flight footage (recorded live video) to follow when the damned winds and rain stop around here.

author: Rerouter
author_rank: Super Contributor
timestamp: September 08, 2012, 10:43:48 pm
content: interesting, however i feel crosswinds would be a moderate problem for such a small quad, still interestered to know how long of a flight time you get out of it ?

author: RCMR
author_rank: Frequent Contributor
timestamp: September 08, 2012, 11:44:09 pm
content: Without the FPV gear onboard, these little quads are good for about 6-7 minutes.The extra drain of the FPV gear (about 250mA) will reduce the flight time (probably by a minute), as will the small amount of extra weight.I'd expect to get around 5 minutes flying.And they handle the wind remarkably well. I've flown them in the turbulence of my back yard with a 15kph wind and experienced no problems at all.

author: RCMR
author_rank: Frequent Contributor
timestamp: September 12, 2012, 08:37:44 pm
content: First flight tests:
Super Solar Boost Charger 500W into 16S LFP - Page 1
Forum section: electronics / projects

author: jacky4566
author_rank: Newbie
timestamp: January 15, 2025, 08:11:29 pm
content: Schematic:https://imgur.com/a/B5QNEFPI very much appreciated this communities feedback on my first design so here is my second attempt at creating a GAN based solar charger. The goal is to create a Solar boost charger for <500W panel with 16S LFP batteries. Independent MPPT of each panel will maximize the power gathered for my marine application where space is limited. I want to clone this product with a 500W capable version.https://sunforgellc.com/product/gvb-8-wp/The principle operation here is using the HRtimer of the STM32F334 to generate a 1MHz PWM for controlling a GAN based boost topography. The HRTimer also supports ending the switching cycles from the internal comparators.Comp 2: Used for detecting maximum inductor current through U7, the negative side is connected to internal 12bit DAC for adaptive reference. Turning off the low side if we exceed the rated limit of the inductor, slope control.Comp 4: Compare U7 output with its reference for negative current. We can then detect when Discontinuous mode is done charging the output cap and turn off the high side.Inductor: 4.7uH chosen using CoilCraft calculatorInput / Output Caps: Taken from looking at reference designs and some basic math for ripple voltages at 1MHz.A secondary current sensor is attached to the output so we can monitor for maximum charge current and perform the MPPT P&O calculations.Charge profile will be software defined for 16S LFP battery.Does this design look complete enough to order dev boards?
Supercapacitor Based USB 5 minutes fast Charger  - Page 1
Forum section: electronics / projects

author: Kedar264
author_rank: Regular Contributor
timestamp: May 03, 2015, 05:04:44 pm
content: A 2.7 v 500 farad supercapacitor can be charged in 5 minutes, if provided with 3A charging current,after that charging cell phone for 30 to 50% battery level is possible.The next level is then to step up the voltage upto 5 volts with minimum 500 ma for usable applicationsHere's my video ,check out and let me know your better suggestions.https://youtu.be/6UqNsCfb_zI

author: Marco
author_rank: Super Contributor
timestamp: May 03, 2015, 05:12:17 pm
content: That's ~1800 Joule, that's ~1/8 Ah at 4V ... that's not 30-50% of battery level (well maybe the level indicator if it's cheating).Are these capacitors fake/rebrands? Can't find a datasheet for 500F, only 400F (Samwha site is down for me though).

author: Kedar264
author_rank: Regular Contributor
timestamp: May 03, 2015, 05:19:40 pm
content: Do you agree ? It is fast charger because of low esr of supercapacitor . normal batteries just dont charge that fast.

author: DanielS
author_rank: Frequent Contributor
timestamp: May 03, 2015, 05:33:54 pm
content: 2Ah x 3.8V average discharge voltage x 3600 seconds per hour = 27360 joules.If you could transfer 100% of your 500F cap's charge to the battery with 100% efficiency, you would charge the battery by about 6%.You would be better off carrying one of those 5-10Ah external battery banks. A pair of those would be cheaper than your ultracap and you simply swap them out instead of cobbling up a fast-charger for the cap.

author: dexters_lab
author_rank: Unknown
timestamp: May 03, 2015, 06:43:52 pm
content: http://www.yodobashi.com/%E3%83%91%E3%83%8A%E3%82%BD%E3%83%8B%E3%83%83%E3%82%AF-PANASONIC-QE-QL103-K-USB%E3%83%A2%E3%83%90%E3%82%A4%E3%83%AB%E9%9B%BB%E6%BA%90-2900mAh-USB%E5%87%BA%E5%8A%9B%EF%BC%9A1%E3%83%9D%E3%83%BC%E3%83%88-%E6%9C%80%E5%A4%A7%EF%BC%9A1A/pd/100000001001763317/About $13 and they work great, i have a few including the larger ones with Qi chargingthe only advantage with the supercap is the fast charging... of the supercap
Supercapacitor Load balancing circuit - Page 1
Forum section: electronics / projects

author: Lt_Flash
author_rank: Regular Contributor
timestamp: March 18, 2020, 05:24:07 am
content: Hi everyone,I'd like to present you my supercapacitor load balancing circuit. There are many of those but they usually consist of a pair of transistors that are partially open during overvoltage of a supercap and thus constantly generating heat due to power dissipation. When transistor is partially open it has a high Rds(on) and this is how most of a cheap supercap load-balancer circuits are made. Yes, it's quite ok from a view of price but I personally do not like that approach and that's why I have created this circuit. It is more expensive but allows the whole circuit to stay at a reasonably low temperatures as it turns MOSFETs on for a short period of time (dependent on input current) and fully opens MOSFETs so they produce a very low resistance and most of the heat dissipation occurs in Rs resistors which you can have as many as you like to suit your input power. Furthermore, this circuit allows a use of any kind of supercaps up to any voltage and number of them, you just need to replicate the schematic when adding more supercaps.You can have a look at the project and all the documents including Gerber files, schematics and PCB here:https://workspace.circuitmaker.com/Projects/Details/LtFlash/Supercap-BalancerThanks and please do not hesitate to ask any questions!
supercapacitor pack balance board - Page 1
Forum section: electronics / projects

author: robint
author_rank: Regular Contributor
timestamp: February 29, 2024, 10:01:50 pm
content: Having seen the earlier work 2019https://www.eevblog.com/forum/projects/chinese-tl431-super-capacitor-balancer/msg2222214/#msg2222214by @wictorhttps://www.eevblog.com/forum/profile/?u=110120In which he uncovered very skillfully the scandalous rubbish produced by Cheap Charlies I wondered now if there was a credible product available for 6 Super Caps in series for 16V auto use that is reliably safe (given the very iffy design using the TL431 )Searched here but no update@Julian did some mod work 3 years ago BUT is it relevant?

author: robint
author_rank: Regular Contributor
timestamp: March 01, 2024, 10:06:41 am
content: BTW I found this very capable explanation here for contributionBut then I saw another cct for this type of board using a mosfet on EB1PC Super Capacitor Balancing Protection Board 16V 83F Single Line Super Farad
Supercapacitors to replace lead acid battery for testing - Page 1
Forum section: electronics / projects

author: dorkshoei
author_rank: Frequent Contributor
timestamp: October 11, 2019, 05:45:31 pm
content: Hi.I find myself often having to debug charging problems on my motorcycles (voltage regulator/rectifier). Or doing various other forms of battery testing.If I have a failed lead acid battery, it's sometimes a pain to rob a working one from another bike.So I was thinking of getting one of the 16v super capacitor setups that are fairly cheap on AliExpress as it's easier than keeping a spare lead acid battery charged (and not sulfating):https://www.aliexpress.com/item/32992323017.htmlMy question is do these have overvoltage protection for the entire unit? In order to protect them if the vehicles voltage regulator has failed? Usually the pcbs that are mounted to each capacitor are for balance protection to ensure one capacitor doesn't get overcharged while the rest of the string is within limits. I asked the seller but my experience is that most sellers on AE know little about what they sell.Thanks for any advice.

author: SeanB
author_rank: Super Contributor
timestamp: October 11, 2019, 07:25:41 pm
content: They have no overvoltage protection, the balance circuit is very limited in the ability to dissipate heat, only really there to handle tiny amounts of imbalance in the terminal voltage on the capacitors, not handle currents over around 50-100mA. If you want to use one, keep a 12V 55W headlamp ( preferably complete and in the housing) always across the capacitor, so as to provide some sort of load, as your bike charger should be able to at least supply 5A to keep it lit , and regulate the voltage to under 14V5 in doing so. Fail to do that and you get whatever is open circuit voltage of your charger, whatever that is, charging the capacitor till something, either on the bike or the capacitor bank, fails rather spectacularly.
Superimposed differential signal - Page 1
Forum section: electronics / projects

author: man_marius
author_rank: Contributor
timestamp: October 17, 2018, 09:34:23 pm
content: I have a system that communicates by a differential signal, that is a superimposed signal of 4 different frequencies, say f1,f2,f3,f4. These frequencies are amplitude modulated, How can I design a system to translate this differential signal into voltages f1->v1, f2->v2 ... f4->v4 simultaneously. The input differential signal can sometimes contain some of the frequencies, but not all.My theory is to have four narrow band filter in parallel each filtering one signal, can that work?

author: moffy
author_rank: Super Contributor
timestamp: October 17, 2018, 11:48:50 pm
content: Yes, if followed by a peak detector each. Or have 4 multipliers each fed with only one of the frequencies then low pass filter the output. Be aware of aliasing in your design. Look up amplitude modulation demodulation, should help.

author: man_marius
author_rank: Contributor
timestamp: October 18, 2018, 05:56:53 am
content: What is easier to implement, the analog filters I have an ideal on how to make them, but it is a bit complicated because of the narrow band (or high Q factor).On the other hand, the demodulator seems easy but I am not knowledgeable in that field

author: macboy
author_rank: Super Contributor
timestamp: October 19, 2018, 02:31:54 pm
content: Is each frequency actually fully AM modulated or just OOK (On/Off Keyed)? The latter case is still technically AM (at 100%) but is much easier to decode.

author: man_marius
author_rank: Contributor
timestamp: October 19, 2018, 03:32:32 pm
content: Its is fully modurated not only OFF/ON

author: moffy
author_rank: Super Contributor
timestamp: October 21, 2018, 10:46:39 pm
content: The MC1496 multiplier is cheap, but requires a few passive components. The BW of the low pass filter is effectively your Q and easy to set.
Supermicro PSU pinout - Page 1
Forum section: electronics / projects

author: EVlab
author_rank: Contributor
timestamp: September 30, 2019, 01:50:09 pm
content: Dear all,I would like to play with some used Supermicro PSU's but can't find any pinout. Can someone help our with a COMPLETE pinout?Part example:PWS-801-1R = 17 pin pairsPWS-1K28P-SQ = 23 pin pairs

author: oPossum
author_rank: Super Contributor
timestamp: October 01, 2019, 12:41:15 pm
content: Code:+12V DCG SMPF /POn SDA SCL A0 A1 IS-------------------------------------------------|---- ---- ---- ---- ---- ---- ---- ---- ----19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 138 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20-------------------------------------------------|--------- --------- ---- ---- ---- ---- ----Gnd +5V SB Gnd -5V GS +12S GS+12V DCG SMA /POn SDA SCL A2 A1 IS +12V-----------------------------------------------------------|---- ---- ---- ---- ---- ---- ---- ---- ---- ---------23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 146 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24-----------------------------------------------------------|--------- --------- ---- ---- ---- ---- ---- ---------Gnd +5V SB Gnd Fan GS - GS Gnd

author: rloc
author_rank: Newbie
timestamp: September 25, 2021, 04:02:59 pm
content: Good day!Help me with Supermicro 1600w psw-1k62a-1r pinout.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 27, 2021, 11:03:33 am
content: Not pinouts, but breakout boards for mining, they are telling wich models are compatible ... some hints maybe ?https://www.parallelminer.com/uncategorized/breakout-board-compatibility-list/Not affiliated
Supervisory circuit for fire alarm panel - Page 1
Forum section: electronics / projects

author: alah
author_rank: Contributor
timestamp: April 12, 2018, 07:18:49 pm
content: Hi, everybody; I have a few BRK 9v batttery operated smoke detectors lying around and decidec to give them some use.I designed a circuit to interface them to a central panel; till now the ALARM function works OK.I have problems designing the TROUBLE function, which should signal if any wire of the zone gets disconnected ( meaning loss of detectionI´m attaching the ALARM circuit. Any ideas, please. THANKS, Alberto

author: C
author_rank: Super Contributor
timestamp: April 12, 2018, 09:00:26 pm
content: Change your logic.Think of your smoke alarm as having an output of NOT Alarm.You have a signal from each smoke alarm that states it is working & not alarmed.A broken wire then becomes ALARM.A dead smoke alarm becomes ALARM.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 13, 2018, 12:52:04 am
content: Quote from: C on April 12, 2018, 09:00:26 pmI don't think calling the fire department just because a wire came loose is a desirable effect.

author: floobydust
author_rank: Super Contributor
timestamp: April 13, 2018, 02:45:09 am
content: To detect cut/open wiring, alarm panels use end-of-line (EOL) resistor. Usually 2k or 4k7 ohm. So the alarm panel sees either 2k ohm (loop normal) or a short (when alarm contact is closed).

author: C
author_rank: Super Contributor
timestamp: April 13, 2018, 02:46:44 am
content: I would think that a house burning down do to a failure is a bigger problems then a false alarm.Creating a signal only on alarm is a failure as you you do not know of failed communications. A signal that gets removed on alarm cures this problem.The need to separate an actual fire alarm from other failures says that the connecting wires have many states.Open connection is one state.A Short is a state.Small current could be actual fire alarm.Larger current controlled by smoke alarm not reporting fire a third state.This larger current could be an energized relay or an on transistor. Both would fail to lesser current reporting the actual alarm.The important point is that the smoke alarm has to actively state it is not reporting a fire.

author: KD4PBS
author_rank: Contributor
timestamp: April 13, 2018, 02:26:52 pm
content: Quote from: NiHaoMike on April 13, 2018, 12:52:04 amExcept that this is exactly how every commercial and monitored fire alarm system works. (and also monitored for "trouble" as floobydust wrote)

author: alah
author_rank: Contributor
timestamp: April 16, 2018, 03:58:20 pm
content: Thanks to all for your replies. I know about EOL Rs, ALARM and TROUBLE signals.TROUBLE would mean loss of comms or battery backup failure.I was trained at SIMPLEX facilities but for maintainance purposes, not designs.Ill stress my brains with floobydust in the meanwhile.BTW, I have some new modules for SIMPLEX 4100 panels which I would like to sell.If anyone is interested, please let me know, THAnKs again.
Supplier for 0.2mm 63/37 Sn/Pb solder in the UK - Page 1
Forum section: electronics / projects

author: cybergibbons
author_rank: Frequent Contributor
timestamp: October 24, 2010, 09:39:19 pm
content: Does anyone know of a decent supplier for 63/37 Sn/Pb solder in the UK?Farnell only seem to carry US stock (and have a £15.95 delivery charge).

author: sonicj
author_rank: Frequent Contributor
timestamp: October 26, 2010, 05:39:10 am
content: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=KE1401-NDfree shipping @ £50

author: TheDirty
author_rank: Frequent Contributor
timestamp: October 27, 2010, 02:30:36 am
content: I've never heard of 0.2mm solder. That would be some freaky thin solder.

author: cybergibbons
author_rank: Frequent Contributor
timestamp: October 27, 2010, 04:32:34 pm
content: I had a small bundle of it that I ran out of - I find it's really useful for smaller work, especially things like tacking wires onto fine-pitch chips, where you don't want to overload and then suck up solder.

author: sonicj
author_rank: Frequent Contributor
timestamp: October 27, 2010, 07:57:31 pm
content: are you sure its .2mm and not .o2"? .2mm is almost as thin as human hair.-sj

author: cybergibbons
author_rank: Frequent Contributor
timestamp: October 27, 2010, 09:02:33 pm
content: Yep, it says 0.2mm on the packaging, but not the manufacturer.I've managed to get hold of 32AWG which is close enough!

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 27, 2010, 11:19:05 pm
content: I picked up some 0.3mm in Akihabara a while ago, which is good for things like touching up QFPs and hand-soldering 0402's - can't say I've felt the need for anything smaller.

author: PetrosA
author_rank: Frequent Contributor
timestamp: October 28, 2010, 11:59:38 am
content: Wow. I have a 16 oz. coil of this stuff I got from a fellow modeler years ago that I've been dragging around with me from house to house and continent to continent. I had no idea it was that expensive!

author: sonicj
author_rank: Frequent Contributor
timestamp: October 28, 2010, 08:29:49 pm
content: hmm... i had no idea it was available that small! is it flux core?-sj
Supplier wanted for 7/0.2mm (0.2mm2) 24 AWG CLEAR / TRANSPARENT wire - Page 1
Forum section: electronics / projects

author: FivePoint03
author_rank: Regular Contributor
timestamp: December 23, 2017, 10:38:40 am
content: I want to extend some Christmas lights for my daughter, and and I am trying to find the same clear / transparent wire, single or figure of 8 would be fine. I'm guessing it's 24 AWG.I just can't seem to find it anywhere!Thanks a lot.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 23, 2017, 11:29:05 am
content: If you have a local Maplin, take a look in their speaker wire section.May be a little thick though. I've seen clear "bell wire" but that was maybe 30 years ago....

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: December 23, 2017, 01:07:21 pm
content: Why not just use enameled wire for that purpose? Many nice fairy lights use that nowadays.
Suppliers for high capacity & high density Li-Po cells - Page 1
Forum section: electronics / projects

author: Jzpwood
author_rank: Newbie
timestamp: July 06, 2017, 08:13:48 pm
content: I've been hunting around for thin (tablet type maybe?) lipo cells in the 10,000mAh range, but have been struggling to find any suppliers, I've been in touch with a company called Yok Energy which seemed really promising, but they've proven very unreliable and difficult to get anywhere with. I'm pretty sure I remember Dave opening up something like this in a mailbag once, but I'd have no hope of finding the video now...I'm only looking for very small volumes at the moment, just a couple for prototyping, but finding cells that aren't in the standard cylindrical form factor at larger capacities is proving fairly difficult.Form factor isn't a huge issue, although I do need cells that are in a cuboid shape and fairly high energy density.I've no doubt this question has been asked before in some form but I can't seem to find anything on here that's relevant.Thanks guys,Jon

author: OiD
author_rank: Regular Contributor
timestamp: July 07, 2017, 03:11:33 pm
content: My first though is to check popular tablets with similar battery capacity and find the size you are looking for on ebay or aliexpress and ask the seller you want to do bussines with him for a decent number of prototypes and try to get the manufacturers datasheet.If the manufacturer already makes the size battery you wont have to hunt down one that will custom make it. Get a few, test them and then if you need production contact the factory.

author: marshallh
author_rank: Unknown
timestamp: July 08, 2017, 02:08:04 am
content: Batteryspace.com will do custom jobs.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 08, 2017, 02:30:25 am
content: Use multiple cells in parallel.

author: Marco
author_rank: Super Contributor
timestamp: July 10, 2017, 03:26:59 pm
content: Just search for 3.7V 10000mAh or 10Ah (or 2500mAh, or 3300mAh, batteries are trivially parallelable after all).

author: Crumble
author_rank: Regular Contributor
timestamp: July 10, 2017, 04:33:56 pm
content: You might want to check into the R/C world, they have a lot of these flying around. They are not particularly thin, but are usually squarish, making it easier to stack them the way you like. What is the application?
Suppliers for PCB hardware (clips, pins, sockets, etc)?   - Page 1
Forum section: electronics / projects

author: Corporate666
author_rank: Unknown
timestamp: February 16, 2013, 09:56:46 pm
content: I am working on a design that is pretty compact and not much room to spare. I would like to incorporate maybe some wire management onto the board itself. Anyone know some companies that make solderable (preferably SMT) hardware? And while I'm at it, what about suppliers of test point loops (not sure what their tech name is - the little loops that are mounted in standoff to allow a mini test clip to be attached)? And what about all sorts of other hardware? I've been looking through Digikey and Mouser but there must be some sort of supplier of all this sort of stuff? I know about Richco and Heyco but they are more plastic stuff, not actual SMT hardware.

author: Thor-Arne
author_rank: Unknown
timestamp: February 16, 2013, 10:14:18 pm
content: I got some PCB Loop-Terminals from RS (stock # 508-0708), they're made byVero Technologies.They have various PCB hardware.Hope that is helpful.

author: hairykiwi
author_rank: Contributor
timestamp: February 16, 2013, 11:40:10 pm
content: I've been developing a similarly compact board recently. I discovered the following companies/products while searching for products similar to the ones you mentioned:www.tag-connect.com/- micro JTAG connectorswww.jst.com/- small pitch pcb headers and connectorsmill-max.com- small pitch pcb headers, test pins, spring-loaded contactswww.yokowoconnector.com- IPX7 rated male cradle connector + pcb headers, test pins, spring-loaded contactswww.coda-systems.co.uk- modular docking connectors, pcb headers, test pins, spring-loaded contactswww.mtc.de/en/smd-contact-springs-type-1-6.html- SMD contact springs

author: dermitza
author_rank: Contributor
timestamp: February 17, 2013, 06:12:56 am
content: Quote from: hairykiwi on February 16, 2013, 11:40:10 pmI'd second JST and mill-max, having worked with their connectors a lot of times. You do however have to factor in the price of the crimp tool(s) (assuming you will be using crimped contacts) which can range in the k's.
Supply Capacitor - Page 1
Forum section: electronics / projects

author: Tnixsw
author_rank: Contributor
timestamp: October 09, 2023, 06:24:52 am
content: Hi all,I need to have a regulator connected to a battery all the time and it is turned on or off by its Enable Pin.I am using a 1uF Tantalum capacitor across the input terminal to GND. If these capacitors have a max hourly usage, I was wondering if this is the best type to use if the capacitor is always connected to the battery.cheersTony
Supply current for battery devices - Page 1
Forum section: electronics / projects

author: @rt
author_rank: Super Contributor
timestamp: April 05, 2019, 07:03:29 am
content: HiAre there some known, general ranges for constant (or mean) current draw a device can safely work with particular battery combinations?ie. 2xAAA or 2xAA, etc.I assume this info is available for each type in battery datasheets, but is there a general rule considering the worst type or brand batteries you’re prepared to use with the device.

author: sleemanj
author_rank: Super Contributor
timestamp: April 05, 2019, 07:14:44 am
content: https://www.eevblog.com/forum/projects/maximum-aa-battery-current-draw/
supply GSM module with a single cell Lithium battery - Page 1
Forum section: electronics / projects

author: alireza7
author_rank: Regular Contributor
timestamp: May 22, 2019, 06:35:46 pm
content: hiDear allI want to design a battery based system which supposed to work for a long time with a single cell 3.6v battery.My GSM module is quectel M66 and works with voltages between 3.3 to 4.2vIf I connect the battery directly to the input of the module, after the voltage of battery became bellow 3.3v the module won't work although the battery still has capacity. so the full capacity of the battery will not be used. I want my gsm module still work when the battery voltage is above 2.5V.My idea is using LTC3203 which is a 500mA Output Current Low Noise Dual Mode Step-Up Charge Pumps with 500ma-5v output and then give its output to mic29302 (3A LDO) to get 4v for the gsm module. but I am concerned with output current of LTC3203. peak current of GSM module is 2A. can I handle it by large capacitors at the input of GSM module?Besides my idea do you have any idea?

author: jbb
author_rank: Super Contributor
timestamp: May 22, 2019, 07:32:00 pm
content: I think you will find that the extra run time you get out of the battery between 3.3 and 2.X V may not be worth the trouble of adding a step-up converter. Depending on cell parameters and temperature, you might only get 10% more out of the battery. Also, your proposed step up converter would be quite inefficient.Some cell phones put a supercapacitor in parallel with the battery to support the 2G transmit current pulses. You’ll need quite a bit of capacitance to do that.How about you stick with the basic battery connection and work to reduce the load current of everything else in the system? The Quectel module is 2G. That’s old technology and I haven’t downloaded the data sheet, but I see that the supply current says ‘as low as 1.3mA.’ That’shugein a battery powered system. Have you looked at the new Cat M1 modules? They are designed for low power low data rate deployments.Finally, a word of caution: if this product is going to be handheld or carried on a belt pouch (or, worst of all, held up to your head), you’ll need to do Specific Absorbtion Rate (SAR) safety testing, which is a giant pain in the ass. If you need that, you should start designing your SAR testright now. I have heard tales of engineers in tears at the test lab when they couldn’t test (and therefore could’tsell) their product.
Supply to battery switcher - Page 1
Forum section: electronics / projects

author: niclatrique
author_rank: Contributor
timestamp: February 03, 2025, 02:21:22 am
content: Hi,i'm designing a simple board with a LoRa tranceiver sending temperature data. 2 identical units will be produced, one for me and one for my friend. Mine will operate on 2 AA batteries and the second board will operate on a 5V supply (stepped down to 3.3V on the PCB).I would like to incorporate a simple automatic switch that will disconnect the herd line supply as soon as the 2 AA batteries are installed. I drawn a simple schematic. Is this going to work ? I have attached the schematicthanks

author: Peabody
author_rank: Super Contributor
timestamp: February 03, 2025, 03:38:24 am
content: If both units are identical, then each unit could operate on either power source, with the external 5-3.3V source having priority if both are present so as to maximize battery life. Typically, that would look like the circuit below. Think of it as a two-diode OR model, with the higher voltage supplying the load, but if that's the battery, the mosfet is turned on to bypass the body diode and eliminate the voltage drop in the battery line. And it's a good bit simpler than your circuit.The P-channel would have to have a very low threshold voltage.
Supply voltage for charging Lithium Ion cells in series - Page 1
Forum section: electronics / projects

author: SenSeS
author_rank: Contributor
timestamp: October 29, 2015, 02:27:42 pm
content: I have been using the bq2057c chip to charge a single cell lithium ion battery and want to use the bq2057w to charge two cells in series. In the datasheet (http://www.farnell.com/datasheets/1777529.pdf) it says on page 5 that the recommended operating conditions for both these ICs is 4.5V to 15V. Does this mean that the bq2057w will charge my series configuration to 8.4V even though I only supply 4.5V?And if it's possible, does the chip step up the voltage to 8.4V? Or is it possible to fully charge two cells in series by supplying 4.5V only?

author: mikerj
author_rank: Super Contributor
timestamp: October 29, 2015, 03:42:47 pm
content: The bq2057c does not provide any voltage step up function, to charge two lithium ion batteries in series you will need to supply at least 8.4+0.3 = 8.7v.This device does not appear to provide any facility to monitor the voltages of individual cells in a two cell battery. If the cells are not well balanced, then this design will not prevent overcharging of the higher voltage cell. I would look for a more appropriate charger design than the bq2057c if you need to charge two cells in series.

author: SenSeS
author_rank: Contributor
timestamp: October 29, 2015, 03:51:05 pm
content: Thanks for your answer. That's good to know.Currently I'm using batteries with an on-cell protection module that will switch off the cell when over- or underdischarged. But I will soon be switching over to using cells without this protection module and will then use this IC in conjunction with the bq2057w:http://www.onsemi.com/pub_link/Collateral/LV51130T-D.PDF. This will achieve the same thing. I've also looked for charge ICs that have this protection on-board but these always have such a high amount of pins and generally cost more than the combined cost of these separate ICs. But using these two ICs should be ok, right? Or am I missing something?
Supplying MAX485 with 5.5V - Page 1
Forum section: electronics / projects

author: Shark
author_rank: Contributor
timestamp: June 23, 2019, 06:52:18 am
content: Hi all,I have a question regarding the MAX485 chip.I found myself in a situation where I have a PCB board finished, with bad luck of supplying 5.5V to a MAX485.Why bad luck? Because it's supposed to get 5.0V +/- 5% ==> 4.75-5.25V.Although when I look at the absolute maximum ratings, it says Vcc max 12V.Hence I am confusedWhich of the two is it?Please help me with interpreting this properly and if I should be worried about the 5.5V supply long-term.I'm also attaching three cut-outs from the manufacturer's datasheet.Thanks!

author: Siwastaja
author_rank: Super Contributor
timestamp: June 23, 2019, 09:10:43 am
content: Manufacturers need to test and specify all the gazillion parameters in certain conditions; otherwise they would be all complex, multidimensional curves. This is tested at 5V.With no "recommended Vcc" section, you need to guess how much leeway you need to add to the 12V abs.max rating. You can read between the lines (from the pinout listing) that the recommended range seems 4.75..5.25V.With no data about the other parameters at anything else but 4.75..5.25V, you need to guess how much the values drift when you run it outside this range.It's very unlikely it would blow up due to overvoltage, you have a massive margin before the abs.max 12V (many digital ICs intended for 5V operation have absolute maximum between 6 and 7V). But they guarantee absolutely nothing about the functional parameters such as current consumption, timing...

author: David Hess
author_rank: Super Contributor
timestamp: June 23, 2019, 07:32:45 pm
content: Because of the high specified absolute maximum voltage, the MAX485 will work fine on 5.5 or even 6 volts. The output levels will be slightly higher but that will not matter for an RS-422/RS-485 application. The inputs are designed to be TTL compatible and should remain so.Quote from: Siwastaja on June 23, 2019, 09:10:43 am5 volts was a good "high voltage" standard for bipolar logic because it comfortably fits within the 5 volt reverse breakdown voltage of common bipolar transistor base-emitter junctions. A higher supply voltage would have required a slower process or extra design considerations which are both present in higher voltage processes designed for analog operation.There were some earlier higher voltage bipolar logic families though.

author: Shark
author_rank: Contributor
timestamp: June 30, 2019, 11:10:38 am
content: Thanks to both for answersAs I do not require the chip to meet any low power requirements, or that any levels/timings are strictly met, I will keep it as is, and improve the PCB for future iterations.Cheers!
surface mount general purpose crystal driver - Page 1
Forum section: electronics / projects

author: ETITsynthesizer
author_rank: Contributor
timestamp: August 19, 2020, 12:10:06 pm
content: I am looking for something like SN74LVC1GX04 in a package larger than the SOT23-6 that is available. I was thinking about maybe using some a 4069 in SOIC 14 but I read a lot of conflicting information online. I am using a 32KHz crystal. apparently there are different operating modes for crystal oscillator circuits. this is getting over my head but I did read about it and I did try. I want to be sure that the 4069 circuit and part number are known working with 32KHz. I don't want to waste time designing something that will never work right. any help?

author: Benta
author_rank: Super Contributor
timestamp: August 19, 2020, 09:59:21 pm
content: https://www.eevblog.com/forum/beginners/crystal-tips-(no-alistair)/
Surface mount optical sensor - Page 1
Forum section: electronics / projects

author: JJalling
author_rank: Unknown
timestamp: December 13, 2014, 08:08:58 pm
content: Hey guys,I'm looking for a reverse mount reflective sensor (surface mount). I need to detect a reflective piece of plastic through a slot in the PCB. I'm not having any luck of finding any at Digikey :-( Am I really the first person that has a need of such a component?BR Jonas

author: RobK
author_rank: Contributor
timestamp: December 14, 2014, 10:24:51 pm
content: Sounds like you just need an IR emitter/detector pair

author: JJalling
author_rank: Unknown
timestamp: December 17, 2014, 11:05:39 am
content: Quote from: RobK on December 14, 2014, 10:24:51 pmDuh .. of course. Thanks/Jonas