hybridfree/eevblog-posts huggingface dataset:
Need an advice on a distance sensor - Page 1
Forum section: electronics / projects

author: miceuz
author_rank: Frequent Contributor
timestamp: June 27, 2013, 10:59:38 am
content: I was offered to make a solution for a theatre - they have three separate platforms which can rise up and down. All of them are driven by a single induction motor thru a reduction box, each platform has a magnetic clutch to couple it to a motor.The vision is to put a separate induction motor for each platform driven by a variable frequency drive and provide a user interface to specify specific height for each platform and move them up and down when keeping relative height the same.I need to measure absolute height of a platform within 5mm. I'm afraid I can't just count revolutions of a motor shaft because of freedom in a reduction box. What else? Ultrasonic pingers? Laser distance sensors? The range is 0.5 - 2m

author: digsys
author_rank: Unknown
timestamp: June 27, 2013, 11:08:00 am
content: For a 5mm resolution, what max height distance are you looking for ?? A system I've worked on with huge trucks and injection mouldingmachines is linear transducers. Very easy to use and all lengths. You don't need one the full length, I've seen many clever methods ofdoing "mechanical" ratio reduction. Those things can get you >1mm resolution and better, so you're good for 5:1 reduction +

author: fcb
author_rank: Super Contributor
timestamp: June 27, 2013, 03:45:12 pm
content: Google "draw wire encoder". These are very simple to install and use, and plenty accurate for 5mm.

author: miceuz
author_rank: Frequent Contributor
timestamp: June 28, 2013, 07:54:43 am
content: Quote from: fcb on June 27, 2013, 03:45:12 pmcan somebody advice me on the good source of those?
Need an alternative to FFC/FPC connector - Page 1
Forum section: electronics / projects

author: polysome
author_rank: Newbie
timestamp: December 29, 2014, 07:38:05 am
content: Hello I have a design for a FPGA PCB with a 60 pin GPIO breakout via a FFC/FPC connector. Its a small board and the connector is too big. Its on the underside of a miniPCIe board... what are my options ? What is a good choice for a more dense connector that is resistant to crosstalk, durable and cheap... has a near 0 height profile... and has a flex cable output ?

author: Psi
author_rank: Super Contributor
timestamp: December 29, 2014, 07:42:18 am
content: I take it soldering the FFC/FPC directly onto the PCB is out of the question?

author: Korken
author_rank: Regular Contributor
timestamp: December 29, 2014, 07:52:08 am
content: Maybe use two connectors? One on each side of the PCB, then you can half the connector size.
Need an alternative/substitute for this connector - Page 1
Forum section: electronics / projects

author: LoveLaika
author_rank: Frequent Contributor
timestamp: October 07, 2021, 02:36:32 pm
content: I'm trying to include a battery to power my Arduino Portenta H7. The board containsthis board-cable connector, and this connector mates with this3-pin female receptacle. The problem is that Digikey doesn't have them in stock. Does anyone know of any alternatives or substitutes that would mate with the Portenta connector? Given its unique shape, I'm at a loss on what to do.For what it's worth, my battery only has two wires, so most likely, I'll only use the first and third pin according to thebattery pin out on the Portenta datasheet. Using a 2-pin variant of the battery connector won't work due to the width, so I'm still at a loss.EDIT: To clarify, all I'm looking for is the mating housing, the JST ACHR-03V-S. I have pre-crimped wires for it already, but I don't have the housing itself.

author: reboots
author_rank: Regular Contributor
timestamp: October 07, 2021, 03:09:30 pm
content: Digi-Key shows the board-mount header in stock, so I assume you just need the mating housing. Arrow Electronics shows JST ACHR-03V-S in stock, although it ships from Japan:https://www.arrow.com/en/products/achr-03v-s/jst-manufacturingGiven distributor stock levels and lead time I recommend buying quickly, and as many as you think you will need.Note that this part is the housing only; you will still need to populate it with contacts. Digi-Key sells pre-crimped leads for the JST-ACH series which might be handy for that purpose:https://www.digikey.com/short/98rzfmwqOctopartandFindChipsare generally useful for finding distributor stock.Digi-Key also has a few other housing parts which are 3-pin 1.2mm pitch, and cosmetically not too far from JST-ACH. If you're really desperate, you could add one of each to your next Digi-Key order and see if anything fits. You would also need compatible contacts, so it's quite a long shot.https://www.digikey.com/short/cr1j4wp5

author: LoveLaika
author_rank: Frequent Contributor
timestamp: October 07, 2021, 03:25:40 pm
content: Thanks for replying. Yes, I got the contacts and everything else. All I'm missing is the mating housing. Unfortunately, I did try from Arrow, but the minimum order is 10 of them, which comes to around $5. Shipping is $40, making it extremely cost inefficient just for the housing, so I can't go with Arrow. I'll have a look at other sites and see if they are viable. Thanks for letting me know about the supply sites. (Actually, looking at the vendor sites recommended by Octopart and FindChips, they either charge way too much for shipping for such a small quantity or they require a minimum quantity that is way too much for my needs)Looking at the board-mount header, the pins are blades with the contacts at the bottom. There's only 5 available female receptacles with the same pin pitch and number of pins. Looking at their shapes, it does appear to be a long shot.
Need an SoC with USB and Ethernet interface, and Linux support - Page 1
Forum section: electronics / projects

author: muthukural001
author_rank: Regular Contributor
timestamp: March 01, 2020, 03:41:56 pm
content: Hello All,One of my project, I am looking for an SoC that should have USB and Ethernet interface basically and it can be low end SoC. In software perspective, it should support Linux kernel. Can anyone suggest any SoC for this?Thanks and Regards,Muthu

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 01, 2020, 03:54:00 pm
content: How cheap are you looking for? There's the Raspberry Pi and similar which have graphics capability, as well as router chips that do not have graphics.

author: muthukural001
author_rank: Regular Contributor
timestamp: March 01, 2020, 04:17:19 pm
content: Hi,Actually, we want to use the development board of the SoC with USB and Ethernet connector. So, I kindly expect that the SoC to be suggested should have development board with USB 2.0/3.0 and Ethernet connector.QuoteDoes it have development board?.If yes, could you share?. Also, is there anything similar to Raspberry Pi 3 ( ARM A53)?QuoteFirst, we looked at Raspberry Pi 3 (ARM A53 processor) development board. Since it does not have Ethernet on its development board, we could not go with it. So, similar to Raspberry Pi 3. SoC without graphics capability is fine.Thanks and Regards,Muthu

author: jmelson
author_rank: Super Contributor
timestamp: March 01, 2020, 05:15:36 pm
content: You should also look at the Beagle Bone Black and similar boards. They have lots of I/O, reasonable graphics output if you want, and two 200 MHz 32-bit microcontrollers for doing interface tasks like bit flipping interface to other components.Jon

author: muthukural001
author_rank: Regular Contributor
timestamp: March 01, 2020, 06:09:20 pm
content: Hi Blueskull,Does V3s support USB HOST feature?...I don't see any boards with USB Type A connectorThanks and Regards,Muthu

author: nctnico
author_rank: Super Contributor
timestamp: March 01, 2020, 06:39:38 pm
content: Quote from: muthukural001 on March 01, 2020, 03:41:56 pmThere are so many out there... how many units do you need? What is your budget? If the number of units is low (<100) then I'd go for a system on a module and not look at the price too much. I like the iMX6 and iMX8 SoCs from NXP. Don't go for a SoC which has a small memory (both RAM and storage) because cutting down the Linux distribution to fit the RAM and storage is going to eat all of your development budget. Choose a SoC which can run a standard Linux distribution because it will save you a ton of time.

author: Dmeads
author_rank: Regular Contributor
timestamp: March 02, 2020, 01:32:42 am
content: https://store.digilentinc.com/cora-z7-zynq-7000-single-core-and-dual-core-options-for-arm-fpga-soc-development/this one is good I have used the chip before has PetaLinux support for emmbedded linux.The below link has some info on embedded linux for older boards but there are some other tutorials onlinehttps://www.xilinx.com/support/university/vivado/vivado-workshops/Vivado-embedded-linux-zynq.html
Need Arduino Serial Help...   - Page 1
Forum section: electronics / projects

author: timcki
author_rank: Contributor
timestamp: March 19, 2016, 11:14:46 pm
content: What I have is the beginning of a robot controlled by an xbox360 controller with a usb shield....I have 2 servos controlled with one joystick, (up, down, left, right)... I have "Serial.print" displaying the movement in a terminal...I have the sabertooth motor driver being controlled by serial pin 1 TX with the other joystick output.......The pan and tilt servos work fine but the two motors are getting less than desired results....Does the serial printing from the servos interfere with the motor signals coming out of TX1?I can post the code if you need to look at it but it is UGLY.....

author: nerd1951
author_rank: Newbie
timestamp: March 20, 2016, 06:00:00 am
content: If I understand your description, it sounds like you are trying to control the Sabertooth from the Arduino's serial port and also have a terminal connected to the same port. If this is the case then the serial print will interfere with the motor control.Since the Arduino only has one serial port, I would use the Sabertooth in "RC Input Mode". Then you can control it from one of the PWM outputs from the Arduino. Then you could control your motors like servos. This would leave the Arduino serial port free for your terminal interface.What would help is if you could post a list of each of the Arduion I/O pins you are using and what each is connected to.

author: FreddyVictor
author_rank: Regular Contributor
timestamp: March 20, 2016, 04:25:17 pm
content: as nerd1951 has said, yes, the debug data you're sending to the console will also be sent to the motors, so may well be causing problems.Arduino platform does have aSoftwareSerial librarywhich allows other pins to be used for Serial communications.

author: Fungus
author_rank: Super Contributor
timestamp: March 20, 2016, 09:49:52 pm
content: Quote from: FreddyVictor on March 20, 2016, 04:25:17 pmAlso every time you upload a sketch...To avoid this you can use a Leonardo. Leonardos have two serial ports, one for talking to the PC and the other one on pins 0+1

author: slashdev
author_rank: Contributor
timestamp: March 21, 2016, 03:55:12 am
content: SoftwareSerial is very inefficient and unreliable, so I'd suggestAltSoftSerialon pins 8 & 9 as a much better alternative. If you can't use those pins, you could tryNeoSWSerialon any other pins. It's not quite as good as AltSoftSerial, but still much better than SoftwareSerial. It has some limitations, but it's perfect for text printing at 9600, 19200 or 38400.Cheers,/dev

author: timcki
author_rank: Contributor
timestamp: March 22, 2016, 01:17:17 am
content: AltSoftSerial sounds like what I am looking for just displaying button presses....Thanks to all that have responded..
Need Boost-Converter circuit for operation of Capacitor as batterie 0-2,7 volt   - Page 1
Forum section: electronics / projects

author: neminiko
author_rank: Newbie
timestamp: December 10, 2024, 08:42:13 pm
content: Hello !looking for circuit design for using Capacitor as batterie system...need either a Booster Converter that can get the voltage up of 0,1 volt to 20 - 100 volt with 10 watt or moredon't know if there are already some circuits(or IC) out there that use Capacitor in parallel for charging and dischargingwould be very helpful since im planing to build a Capacitor BMS from scratch

author: Xena E
author_rank: Frequent Contributor
timestamp: December 11, 2024, 01:26:17 am
content: You do realise that 100mV at 10W is 100Amps?
need capacity sensor which can detect volume after power reboot - Page 1
Forum section: electronics / projects

author: ivi_yak
author_rank: Regular Contributor
timestamp: February 02, 2018, 11:52:25 pm
content: A lot of capacity sensors which I use after power off and on going to recalibrate after power on and lost previous capacity

author: eliocor
author_rank: Unknown
timestamp: February 03, 2018, 12:25:22 am
content: ??

author: amspire
author_rank: Super Contributor
timestamp: February 03, 2018, 12:35:36 am
content: Quote from: ivi_yak on February 02, 2018, 11:52:25 pmWe are not sure what you are talking about. Capacitance Sensor? Touch sensor? Maybe battery charge state?What is the thing you are turning on and off?
Need checkup for my USB -> DMX & 5way splitter project - Page 1
Forum section: electronics / projects

author: 3dBi
author_rank: Contributor
timestamp: May 15, 2020, 08:19:54 pm
content: I'm trying to make a USB to DMX box with 5way splitter on one board. Could you please check my schematic for beginner errors?This device is intended for my personal use, to get better light show for my band playing weddings, parties etc.Solder pads IN+ and IN- are going to DPDT switch to switch between external XLR input and USB stuff coming out of pads A and B.Also do outputs of 485 need to be biased?Inspiration to do this came from these sources:http://juvar.mbnet.fi/blog/wp-content/uploads/2018/09/schematics-rev2.jpghttp://www.chameleon.rs/e035020.pdf
Need circuit to simulate HVAC is wired to Nest Smart Thermostat - Page 1
Forum section: electronics / projects

author: garryweil
author_rank: Newbie
timestamp: April 07, 2017, 10:04:04 pm
content: Folks,Lately I am doing a lot Smart Home demos and I need a way to "fool" my Nest thermostat into thinking a real HVAC system is connected. Otherwise I get an error message on the Nest thermostat display that will not go away.I have a 2 year degree in Electronics Technology so I understand schematics and such.Thanks

author: Seekonk
author_rank: Super Contributor
timestamp: April 07, 2017, 10:10:19 pm
content: Many electronic thermostats operate much like a current loop sensor. Since these should work with as little as two wires, a 47 ohm in series with a 24V transformer should do the trick.

author: ratio
author_rank: Regular Contributor
timestamp: April 07, 2017, 11:46:33 pm
content: Why not a handful of 24VAC contactors? The load should be indistinguishable from a "real" system, you can use the contacts to light up indicators to show what's happening, maybe a little fan on the blower contact?

author: calexanian
author_rank: Super Contributor
timestamp: April 09, 2017, 01:27:09 am
content: +1 vote for a 24 volt transformer (You can use a door bell one) and a resistor in series to limit the current to a reasonable level.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 09, 2017, 01:37:14 am
content: Some 24V relays, a Peltier to provide a little heating/cooling (run it at a low voltage like 3.3V to slow the temperature change to a reasonable value), and a PC fan for the fan.

author: Vtile
author_rank: Super Contributor
timestamp: April 09, 2017, 05:13:42 pm
content: Look at the manual of the sensor to see what type of signal it do need from/to HVAC. If there is no manual and a such information, change provider of goods.
Need clarification with LS18 switch debounce chip connectivity. - Page 1
Forum section: electronics / projects

author: MarkS
author_rank: Unknown
timestamp: June 22, 2023, 07:48:31 pm
content: Datasheet:https://www.logiswitch.com/wp-content/uploads/LS10-Series-ICs-Technical-Details.pdfI'm using this chip for a project. Yes, I know there are cheaper ways to do debounce, including in software, but this is convenient for me. Anyway, I'm a little confused by the datasheet. If I'm reading this correctly, it sounds like I connect one leg of the switch to ground and the other to the input, but the output is normally high. So, am I to assume that when the switch is open the output is high? And if that's the case, how can the inputs and outputs have the same polarity, as stated, "Outputs and inputs are of the same polarity and may be selected for use as active high or active low."?This datasheet is written very poorly. Any help?

author: CountChocula
author_rank: Unknown
timestamp: June 22, 2023, 09:18:41 pm
content: As I understand, the input pins of the IC include a resistor that pulls them up to VCC, and the output pins follow the inputs (minus debouncing, so there is a ~20ms delay). By connecting a switch with one leg to ground and the other to one of the inputs, you can then set things up in two configurations:With a normally-open switch, the output is low when the switch is depressed, because pressing the switch shorts the input pin to ground.With a normally-closed switch, the output is high when the switch is depressed, because the opposite conditions will occur.—CC

author: MarkS
author_rank: Unknown
timestamp: June 22, 2023, 09:28:52 pm
content: Quote from: CountChocula on June 22, 2023, 09:18:41 pmMakes sense! Thank you.
Need Custom Build Progressive to Interlaced Signal Converter HDMI>HDMI - Page 1
Forum section: electronics / projects

author: Videodrome
author_rank: Newbie
timestamp: May 22, 2024, 07:40:13 am
content: I'm not sure if this belongs here or in the ‘jobs’ section, but here goes...I'm looking for someone who can build a device that converts any progressive signal into the corresponding interlaced one. While many converters exist, I need one that supports higher refresh rates than the standard 30i/60i (60Hz) specification. I've tried the Barco Folsom ImagePro HD and the RGBLink VSP628PRO without success—they can't handle the timings send from my computer.To avoid confusion with the interlaced and progressive terminology, I'll refer to everything in terms of Hz from now on. For instance, 60i and 60p both mean 60Hz. (where 60i loses half the information due to the interlacing fields)Here's an example of what it basically needs to do:Input: 1920x1080p @ 84Hz >>> Output: 1920x1080i @ 84HzInput: 1280x720p @ 120Hz >>> Output: 1280x720i @ 120HzIt should auto-recognize the input signal’s resolution unless it significantly increases costs.A resolution selector with a few EDID choices could be a viable alternative.Specifications:* Max resolution: 1920x1080p 100Hz to 1920x1080i 100Hz* Timing: CVT standard (no reduced blanking)* Low latency: 1.5 frames max, ideally less* HDMI input and output* Audio is not a concern; video signal only* Durable and robust connectors; outer shell aesthetics are not importantThis is a personal project, and there’s no rush.I need a rough cost estimation to see if it’s worthwhile.When successful, I might request 2 or 3 more units as backups.If such a converter already exists and meets these criteria within budget, please let me know.Or if there are better places where to ask this question.I'd appreciate any recommendations.Thank you.

author: kundewayne
author_rank: Newbie
timestamp: May 27, 2024, 03:52:38 am
content: Quote from: Videodrome on May 22, 2024, 07:40:13 amYou need a gadget that can change progressive video signals (p Hz) into interlaced signals (i Hz) at 60 Hz or higher refresh rates.Neither the Barco Folsom ImagePro HD nor the RGBLink VSP628PRO, two of the current converters, are compatible with the precise PC timings.
Need Data on WP90321Lxx Series Diodes - Page 1
Forum section: electronics / projects

author: MrAl
author_rank: Super Contributor
timestamp: January 26, 2015, 01:36:17 pm
content: Hello there,I have looked around and was unable to find data on a diode:WP90321L75Aso i have no idea what this diode can and can not do. It may be a regular type diode,Schottky, or even a zener.If data on this exact part number is not found, i might settle for the same base part number data sheet such as:WP90321L10Afor example. I may be able to extrapolate the spec's from that.The min specs would suffices i guess if a data sheet is not available, such as type, current, reverse voltage.Thanks for whatever information you can find.
Need description of SMA connector - unpopulated - Page 1
Forum section: electronics / projects

author: xrunner
author_rank: Super Contributor
timestamp: January 26, 2019, 02:36:48 pm
content: Hey guys,I need the name or description of the SMA connector shown in the pic - but I want to buy somewithout any component installed.The one shown is a 50 ohm load. What is the name of the part if it has NO load or component installed? You can see the 50 ohm load is soldered in. Can they be bought "empty"?Thanks!

author: Xnke
author_rank: Regular Contributor
timestamp: February 04, 2019, 03:14:46 am
content: That is an SMA connector for rigid or semi-rigid coax, nothing special.

author: xrunner
author_rank: Super Contributor
timestamp: February 04, 2019, 03:45:35 am
content: Quote from: Xnke on February 04, 2019, 03:14:46 amOK thanks - wasn't sure but that was what I was leaning towards since the time I asked the question.
NEED DETAILS FOR DICK SMITH K3602 EA EPROM PROGRAMMER - Page 1
Forum section: electronics / projects

author: simon christo
author_rank: Regular Contributor
timestamp: August 17, 2020, 03:04:49 am
content: Hi there! I'm looking for some details on the DICK SMITH kit K3602 from Electronics Australia Magazine, around the year 2000.It's got 2X ZIF Sockets, one for reading and one for writing, it's for a parraell port too.If anybody has any details about it, let me know.Thanks Simon.

author: greenpossum
author_rank: Frequent Contributor
timestamp: August 17, 2020, 03:14:05 am
content: There's a thread in the Austech forum from 2009 here:https://www.austech.info/showthread.php/26919-Eprom-ProgrammerI couldn't see any resources to download, maybe you have to register first.It sounds like this might be the same design:http://archive.siliconchip.com.au/cms/A_30475/article.html

author: austfox
author_rank: Regular Contributor
timestamp: August 17, 2020, 11:01:46 am
content: I picked up one of these units a few years ago. I don't have the article, but I believe it is from EA January 2000. Copies of the article would be available to order from Silicon Chip.I have software from the 1994 design, although I haven't attempted to get it up and running, so not sure if it is compatible. Dave Jones also wrote some software for the 94 design.I can help you out with component values if needed?

author: simon christo
author_rank: Regular Contributor
timestamp: August 19, 2020, 05:25:19 pm
content: Hi again.Apparently, the 5.5MB PDF listed isn't on the net anymore! Anyway, I found some PCB numbers that may help;EA 93eep7a for main PCB, andZA-1331 for LED,ZIF socket PCB.Thanks Simon.

author: greenpossum
author_rank: Frequent Contributor
timestamp: August 19, 2020, 06:09:03 pm
content: Maybe this matches what you have?http://www.evans-pure.net/
Need EE opinion: Will this blow up? - Page 1
Forum section: electronics / projects

author: mrratburn
author_rank: Newbie
timestamp: February 27, 2014, 04:58:19 am
content: Good day,So I'm working on a portable raspberry pi handheld and I'm going to include a Li-Ion rechargeable battery. I want to be able to charge the battery within the handheld. Because Li-Ion batteries are famously picky about their voltage and current ratings I'm using a charging IC to charge it. I've calculated the value for the sense resistor using the datasheet, but everything else is the same.Can an EE or someone with a little experience with this double-check my charging circuit? I've already ordered the parts so it's too late to change them unless it's seriously wrong.Here's my parts list with hyperlinks:1 x7.4v 2200 mAh Li-Ion1 xIC CONTROLLER LI-ION 8.4V 8MSOP1 xMOSFET P-CH 35V 12A TO-220-31 xRES 0.1 OHM 3W 1% AXIAL<-- this is the sense resistorThe datasheet for the batteries ishere.The datasheet for the charging IC ishere.Here is a sample application circuit taken straight from the datasheet:Here is the circuit with component labels. NOTE: I'm using the 73844, which charges a dual-cell battery and has no temperature sensing. The input will be a 9V 1A wall-wart. Rsense is 0.1 ohms.The Rsense was calculated by Rsense = Vfcs/Ireg. Vfcs is a constant 110 mV. so .110 V/1 A = .110 ohms. Since I couldnt find a .01 ohm resistor, I'm just going with .100 ohms.So if you guys can, I'd be much obliged if you can double-check that this works and I'd like to know if I should leave the values for the other resistors and capacitors the same as the values on the sample circuit.Thanks

author: treespicer
author_rank: Newbie
timestamp: February 27, 2014, 04:12:46 pm
content: You're charging your battery at 1/2C, so you'll need to increase the timer capacitor or it will stop charging prematurely. Also, a lot of power will be dissipated in the FET when you're charging a low battery, so you'll need to heat sink it. Alternatively, you could charge at a lower current, but it'd take longer to charge.I don't know what your use case is, but if you want to be able to run the device while it's plugged in I'd use a power path/charger with a single-cell battery and a 5V input. Then boost the output.
Need extra opinions on exisitng reference voltage circuit. - Page 1
Forum section: electronics / projects

author: floxia
author_rank: Contributor
timestamp: February 03, 2024, 11:30:34 am
content: I have the attached reference voltage circuit used with a CS5530 ADC to read a loadcell voltage, the 5V excitation and the voltage input of the divider come from a SPX3819.I did not decide to use an external 2.5V reference voltage chip as I was worried that the sensor supply voltage will need to be proportional to the 2.5V reference, causing systematic errors in the sensor readings, which cannot be eliminated using software filtering.Furthermore I have observed four different circuits of commercial instruments that utilise the same chip and they all have a simple voltage divider as a reference voltage.I had 5.1k resistors available although they were 1% and 100ppm, which I scrapped as there was too much drift due to temperature, I have taken two 10k resistors from an existing commercial circuit that utilises the same ADC and the temperature drift drastically improved although I want to try a pair of 0.05% 10ppm resistors to see if they perform well (I have no information in regards the 10k resistors). I am happy already with the circuit but I'd like to get the best performance I can without revolutionise the circuit too much as it is already on a PCB.I am open to suggestions, if there is anything that I can try which I have not considered yet for example a resistor and diode or else. Also feel free to drop some ideas for future board revisions!
Need feedback on ADC input circuit (AD9288 + trigger) - Page 1
Forum section: electronics / projects

author: hupfer21
author_rank: Newbie
timestamp: March 28, 2025, 10:50:56 pm
content: Hi everyone,I’m trying to design a DIY oscilloscope using an external AD9288 (40 MS/s ADC). Since this ADC only accepts positive voltages, I needed a circuit to offset the input voltage from the probe. I also wanted a triggering mechanism, so I split the probe input to compare it with a trigger voltage reference.Below is my attempt at this:Circuit Description:First OP-AMP:Inverts the input with a near-unity gain (I added a 47Ω series resistor to the non-inverting input to slightly reduce gain and prevent clipping near 0V/3.3V).Adds a 1.65V offset (half of 3.3V).Second OP-AMP:Re-inverts the signal (unit gain) and adds 3.3V offset.The output matches the probe voltage but is centered at 1.65V (for the ADC).Third OP-AMP (Schmitt Trigger):Compares the split output to a reference voltage.Triggers when the input exceeds 3.3V ± 3% (set by R6/R5).I chose a Schmitt trigger over a comparator to avoid false triggers due to noise.Simulation Results:Probe input: 100 kHz sine wave (±1.65V).Trigger threshold: Set to 1V to verify the Schmitt trigger outputs a clean 3.3V interrupt signal to the MCU.Thanks in advance for your help!

author: moffy
author_rank: Super Contributor
timestamp: March 29, 2025, 12:21:09 am
content: Use a proper high speed comparator for the trigger, opamps are not well suited for high speed comparison/switching/logic.
need find similar mechanical encoder - Page 1
Forum section: electronics / projects

author: han
author_rank: Frequent Contributor
timestamp: May 19, 2014, 06:18:21 am
content: I need replacement for rotary encoder belowElectroswitch Inc. 701-04-16i only can find in Mouser, with ridiculous price and qty.anybody knows the replacement with exact pinout and similar shape ?thanks...
Need Good Mechanical 2x20 0.1 in Female Socket - Page 1
Forum section: electronics / projects

author: pctj101
author_rank: Newbie
timestamp: September 03, 2015, 05:22:45 am
content: I've run into a problem recently with "generic" female pin sockets and really crappy "internal connectors".The main problem is that it is really easy for the contacts to lose connections because they are so small/weak/crap.I've pulled one out of the connector to show.This is bigger problem when vibration is factored in.Do any of you have any recommendations on brands/models/series I should look into?

author: dave_k
author_rank: Frequent Contributor
timestamp: September 03, 2015, 07:18:23 am
content: Something like this?http://www.te.com/usa-en/product-1-215307-0.htmlIf you have a look at the product drawing you'll see the contact is made of 2 sprung fingers. The documentation for the HV-100 series gives vibration test results.
Need guidance.  MCU, wifi, web app, acoustic sensing.   - Page 1
Forum section: electronics / projects

author: viper
author_rank: Regular Contributor
timestamp: August 05, 2025, 03:06:23 pm
content: I've been trying to get a potential commercial project done for years. I have recently realized my EE brother is never going to make enough time to get this done. I'm insanely frustrated but I know I just need to go alone here. I know exactly what I want/need, and I know how it needs to function, but I'm now drinking from a fire hose in terms of soaking up knowledge to get it going.Basically I am doing sonic distance measuring where I need to log the data and be able to interface that with a web app. I am familiar enough with mobile vs web apps to know a web app is the right choice for this.I'm not sure if the people with experience are on forums or what? I need to select everything from scratch at this point. MCU hopefully with acoustic features built in? How to approach the Wifi connectivity? Iot?I guess I don't have much interest in getting test parts that don't suite all the needs, only to have to redo a bunch of work with say a full featured MCU. IE, I want to test the actual components that would be used in a commercial device.Can something like this actually get done in the USA with a reasonable budget? I know in the past we were just shocked that even a few of our parts cost more than some turnkey commercial devices because they interface with China. I refuse to work with them for much of this.If there are better sites or forums to learn and decide a path for a web app, please inform me. Sorry for the scatterbrain post. I have a lot on my mind today and trying to build an action plan and set some goals. I want this DONE....
Need HDMI to Flying Leads .1" Pitch  - Page 1
Forum section: electronics / projects

author: yanir
author_rank: Regular Contributor
timestamp: December 06, 2011, 03:37:14 pm
content: Does anyone know if something like this exists off the shelf? I want a hdmi connecter on one end and all the pins broken out to .1" Pitch female connectors. I'd take something other then hdmi on the other end too, just need something with a lot of pins and low profile.Anyone come across something like this?

author: olsenn
author_rank: Frequent Contributor
timestamp: December 06, 2011, 03:58:09 pm
content: I don't know about a .1" spacing; there are 19 pins to an HDMI connector if I remembered correctly, and these types of connections are typically used for high-speed serial data, which I don't believe would would work out so well if just implemented on a breadboard (needs short wires, low capacitance etc).If you want a low profile connector with many pins which may be soldered into a custom pcb, then you can certainly get female-to-male HDMI, DVI, VHDCI, or any other connector. If nothing else works, you can always try soldering dead-bug style, but a simple ribon cable in an IDC connector is always worth considering.Good luck!

author: yanir
author_rank: Regular Contributor
timestamp: December 06, 2011, 04:02:06 pm
content: I won't be implementing hdmi. I just want a high conductor count with a small connector on one end and hobby friendly .1" pitch on the other. I'm looking for a finished product that could be part of a kit.

author: olsenn
author_rank: Frequent Contributor
timestamp: December 06, 2011, 04:17:01 pm
content: You may be able to find something like that that already exists, but more than likely you will need to create a breakout board for it yourself. It's a pain having to wait a month to get the part you need, but the footprints for most standardized connectors are already available for, lets say, Eagle, and it will fit within the limits of the free version no problem.First I would look online for a breakout board though, or possibly use something like this for testing until you are ready to mass produce your project:http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,648,847&Prod=VMOD-BB

author: yanir
author_rank: Regular Contributor
timestamp: December 06, 2011, 04:31:32 pm
content: Custom break out board is a good idea. Easier to do than a custom cable at low quantities. Thanks!

author: Short Circuit
author_rank: Frequent Contributor
timestamp: December 07, 2011, 12:49:12 am
content: You might want to check these connectors, quite easy to sodler or so it seems;http://www.hdequipment.eu/hdmi-connector.html

author: yanir
author_rank: Regular Contributor
timestamp: December 07, 2011, 03:55:59 pm
content: That might work well too. Decisions, Decisions...
Need help! LCD PC window project - Page 1
Forum section: electronics / projects

author: CoolAEW
author_rank: Newbie
timestamp: April 30, 2017, 08:19:55 pm
content: Hello, everyone!I'm currently trying to mount an LCD panel inside my PC case window. But I've run into a problem, for the panel to work I need to connect the top driver PCB with the left driver PCB. The panel used a 10*30mm (W*L) 20pin ribbon cable(picture attached), but I need a longer one, 20cm or so, as I'm folding the PCB's away from the panel to make it transparent. Does anyone know where I can get ahold of one?Thanks!

author: sanwal209
author_rank: Regular Contributor
timestamp: April 30, 2017, 09:13:37 pm
content: pitch?

author: CoolAEW
author_rank: Newbie
timestamp: May 01, 2017, 11:43:25 am
content: I found what I needed shortly after writing this post, but were not able to delete the post.
Need help.... Got Help, Thanks (AD7873 Touchscreen digitizier) - Page 1
Forum section: electronics / projects

author: MyElectronsFellOut
author_rank: Regular Contributor
timestamp: July 04, 2016, 10:03:32 am
content: So I'm working on a new project involving touch screens (my first foray).I'm using the following parts:AD7873http://docs-europe.electrocomponents.com/webdocs/0712/0900766b80712812.pdfDT028ATFT-TShttp://docs-europe.electrocomponents.com/webdocs/120b/0900766b8120b294.pdfMy problem breaks down as follows.How do I read the data? The datasheets and app notes are next to useless (to me anyway). I'm running this on an ATSAM3x8e micro controller using the SPI interface to talk to the touchscreen digitizer but have no idea what data I need to send it in order to get the touchscreen coordinates.Does anyone have experience with these parts or any reference code?Thanks.

author: Kilrah
author_rank: Unknown
timestamp: July 04, 2016, 10:54:01 am
content: Pages 19-21 of the AD7873 datasheet tell you all you need.You can either bitbang the required data, or as it is apprently SPI-compatible use an SPI module of your microcontroller to send/read the data if it has one.Basically you send an 8-bit control word with the bits set accordingly to the operation you want the chip to perform, and you then send 2 more dummy 8-bit words (contents arbitrary as long as the START bit is not set) in order to read the response.Find yourself some SPI bus docs to get a more general background over how it works.

author: MyElectronsFellOut
author_rank: Regular Contributor
timestamp: July 04, 2016, 02:29:50 pm
content: I understand the SPI interface and how to communicate with the chip, what I don't understand is how to get the X and Y coordinates. The table on the datasheet is not very clear as there are various different measurement modes. It doesn't tell you what the output is for each different code except for the one that says "Outputs Identity Code 1000 000 000".

author: bktemp
author_rank: Super Contributor
timestamp: July 04, 2016, 02:49:14 pm
content: See table 5 on page 14:You need two measurements: Analog Input set to Y+ and X+ gives you raw data for x and y position.

author: MyElectronsFellOut
author_rank: Regular Contributor
timestamp: July 04, 2016, 03:15:17 pm
content: Thanks for that.

author: Gyro
author_rank: Super Contributor
timestamp: July 04, 2016, 04:32:49 pm
content: Just a quick hint, just think how confusing things would get if everybody titled their threads 'Need help...'P.S. The good news is that it's not too late to change it. Just go to your original post and edit the 'Subject' line. It usually gets you more views too.

author: MyElectronsFellOut
author_rank: Regular Contributor
timestamp: July 05, 2016, 07:09:26 am
content: You are right, Think I was just having a very lazy day mentally lol

author: Gyro
author_rank: Super Contributor
timestamp: July 05, 2016, 08:39:20 am
content: QuoteWell I was thinking more along the lines of 'AD7873 Touch Screen Digitizer help' but whatever floats your boat.
Need help with an output capacitor  - Page 1
Forum section: electronics / projects

author: illusive
author_rank: Regular Contributor
timestamp: February 01, 2016, 10:56:09 pm
content: Hi all,I'm trying to optimize the output filter for a buck converter. The IC is theLM2676. It has a switching friquency of 260KHz. I'm having hard time choosing the output filter capacitor after the inductor (47uH), mainly with what ESR should it be. I have to choices: The first one is two 330uF 60mohms ESR capacitors in parallel (for a total of 660uF and 30mohms ESR). The second one is a two 470uF 30mohms ESR in parallel (940uF 15mohms ESR total). The datasheets for these buck converters are saying that the lower ESR the better, but also that if the ESR is too low there may be instability, but they don't go into details. And now i cannot choose should i go with lower capacitance and higher ESR or the other way round. I'm trying to optimize the filter for the lowest ripple possible.

author: uncle_bob
author_rank: Unknown
timestamp: February 02, 2016, 12:30:35 am
content: HiAnother thing to consider is the ripple current rating on the capacitors. Often that is a bigger deal than the ESR.Have you tried the canned design software that TI has for that IC? The main reason to use those old parts is the software. A lot has come along in the 15 years since they came out. If the software isn't helping you ... I'd look at some newer parts.Bob

author: cat87
author_rank: Regular Contributor
timestamp: February 02, 2016, 06:59:55 am
content: The two 330uF in parallel sound OK to me. It's not always a good idea to go with the lowest ESR because the lower the ESR, the larger the current spikes will be when the load changes suddenly.If either old fashioned pen-and-pencil calculations or design software from TI do not help, then you can always use trial and error and see which option gives you the best result over a wide range of loads.This are my two cents
Need Help building a simple voice recorder prototype - Page 1
Forum section: electronics / projects

author: drboyd41
author_rank: Newbie
timestamp: May 24, 2016, 02:41:35 am
content: I need help from someone in the Atlanta, GA area to advise or to build a prototype of a very simple hand held voice recorder to be mass produced. Would be similar tohttp://www.amazon.com/Multifunctional-Rechargeable-Digital-Recorder-Dictaphone/dp/B00FPI1HQ8/ref=sr_1_62?s=electronics&ie=UTF8&qid=1464057323&sr=1-62&keywords=digital+voice+recorderbut with a few minor modifications. Please email to discuss.

author: Buriedcode
author_rank: Super Contributor
timestamp: May 24, 2016, 10:36:41 am
content: These days, with aliexpress, fleabay, and many other places that sell mass produced products over a very wide range of quality and price, I suspect it would be more expensive to develop your own. Unless something has very specific requirements, functions, reliability you'll be better off buying up products in bulk.With that said, just for voice recording, there are plenty of 'sound recorders' using micro's floating about on the web. The simplest I ever made recorded in 12-bit quality at 16kHz and just used an AVR, a flash chip, and a transistor driving a speaker. The cost of those parts, plus the PCB and the most difficult part - the housing, so its user friendly - would probably be more than purchasing a much 'better' product.For one-off hobby, or making 'toys' to play with, designing something yourself is great, but for industry, there is a reason why so many chinese factories advertise for custom manufacture - you can decide the level of quality, and the cost is often very low for high volume parts.
Need help building Pentium MMX VRM module (re: IBM PC) - Page 1
Forum section: electronics / projects

author: sofakng
author_rank: Regular Contributor
timestamp: June 08, 2021, 05:23:11 pm
content: The IBM PC 330/350 models offered CPUs up to Pentium MMX 233 but they excluded the 2.8v VRM module unless it came with an MMX CPU. However, the pin headers are still present on the motherboard and the BIOS supports it without any issues.The IBM part number (FRU) is76H3658which corresponds to a Semtech MP55C-3.3-2.8 VRM (datasheet).The VRM module appears to be a simple 30-pin adapter with a 5-pin voltage regulator and a few resistors/capacitors:I've compared the Semtech datasheet and used a multimeter to diagram the pins on the IBM motherboard:This is about as far as I can go myself so I'm hoping somebody with more knowledge can help out?

author: ve7xen
author_rank: Super Contributor
timestamp: June 09, 2021, 12:42:28 am
content: I think it is probably an LT1580 design based on the pinout and specs. Expensive, but still available. The diode is between 5V and the regulator output. The rest you should be able to replicate just reading the regulator and VRM datasheets and making educated guesses about component values, it even includes board dimensions. You'll have to measure the connector pinouts / consult some additional photos to try to find a match. I think it might be Amphenol 66527-015LF on the VRM side, which would mate with a standard 0.1" header on the motherboard, but hard to say for sure from the photos.If you don't care about replicating the original design exactly, it would be cheaper to replicate the functionality with a "modern" switchmode converter like the jellybean LM2596.What did you need help with?
Need help converting BLE to ESP controled LED! - Page 1
Forum section: electronics / projects

author: RaptorHunter
author_rank: Newbie
timestamp: August 30, 2021, 07:43:09 am
content: Hi everyone,I have a fiber optics star ceiling with a Bluetooth low energy LED "engine", I want the integrate it to my home assistant but it seems like it's very difficult to control Bluetooth devices with home assistant, I am thinking about replace the board inside the light engine with a custom one controlled by an ESP32 or an ESP2688.The light engine has 2 high power RGBW LED chips and a 28BYJ-48 motor, I plan to use the following, I need to know which ESP board to get and how to connect it.Thank you
Need help debugging a board utilizing the Lumissil IS31FL3733 LED driver - Page 1
Forum section: electronics / projects

author: pini.grigio
author_rank: Contributor
timestamp: September 19, 2023, 07:12:40 pm
content: Hi all!I received a board fabricated by JLCPCB today incorporating a pretty boilerplate RP2040 setup with the IS31FL3733 12x16 LED matrix driver.https://www.lumissil.com/assets/pdf/core/IS31FL3733_DS.pdfhttps://www.lumissil.com/assets/pdf/core/IS31FL3733_EB.pdfI have a 12 cathode by 16 anode led matrix display, and I can confirm the LEDs themselves are fine and turn on when I drive them manually.The RP2040 and power circuitry also work fine, and I am able to see the IS31FL3733 chip on the i2c bus, and it behaves as expected - for instance I am able to write a value to the only R/W register and read it back.However - it does not drive the LEDs no matter what I do.I've read through the datasheet and compared my code with existing code examples to make sure I am configuring it right - but no luck.A few points and observations I have made so far -1. I am driving the IC (and thus the LEDs) with 3.3V, which according to the data sheet should be fine?2. My leds are 2.0V forward voltage3. There is no voltage on the Rset pin, which is connected to ground via a 33k resistor - which definitely seems to be part of or a result of the problemI'm not sure how to debug this issue and would appreciate suggestions from anyone who has had experience with this chip or similar ones.I'm adding my schematic and will gladly share any more information with anyone willing to assist.[ Specified attachment is not available ]Much appreciated!

author: temperance
author_rank: Super Contributor
timestamp: September 19, 2023, 08:03:58 pm
content: I have no idea why you renamed Rext to Rset but:Iout is: (840 x GCC) / (Rext x 256). See page 21 of the data sheet.

author: pini.grigio
author_rank: Contributor
timestamp: September 19, 2023, 08:59:36 pm
content: That's how the pin was named in that footprint.I have set Rext to 33.6k, the resistor is marked DNP since I'm manually soldering it
Need help decoding schematic symbol I haven't seen before - Page 1
Forum section: electronics / projects

author: ITman496
author_rank: Regular Contributor
timestamp: July 14, 2016, 02:58:50 am
content: So for those 3 pin looking things that link various things together....... are those pots or jumper link pins?

author: ebclr
author_rank: Super Contributor
timestamp: July 14, 2016, 03:08:13 am
content: Cab be a switch or a connector

author: ITman496
author_rank: Regular Contributor
timestamp: July 14, 2016, 03:14:21 am
content: So for making a test pcb, putting a 3 pin header there is a safe bet?

author: altaic
author_rank: Unknown
timestamp: July 14, 2016, 06:43:45 am
content: Without knowing what Q is, I'm going to say they're jumpers. That's based on the assumption that Q is some sort of audio device, from the L/R thing. If I'm wrong, a trimpot shouldn't make your day sour; give it a go and see what happens. Worst case, you'll be able to deduce what the difference is and you won't let the magic smoke out.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 14, 2016, 09:28:12 am
content: Undefined three-pin header type part. Could be jumper, header/connector, switch... even a transistor if one was lazy enough.Tim