hybridfree/eevblog-posts huggingface dataset:
Image Detection Question - Page 1
Forum section: electronics / projects

author: docmur
author_rank: Regular Contributor
timestamp: August 13, 2016, 04:39:03 pm
content: Hey GuysI want to build camera based image detection into a project, just for fun. I've used image sensors in the past, but they were intensive resource wise and sucked power like it was free.I've also used web camera's in the past and used raw image processing, but again it was very resource intensive.What are some ways people have done this? What I want to do in effect, is take pictures of my environment every X seconds and process them for edges and surfaces.I know I could grab a number of different image sensors or a web camera and just throw this together, but does anyone know of a more elegant solution?Again this is just for fun, not a serious level project.ThanksDocmur

author: helius
author_rank: Super Contributor
timestamp: August 13, 2016, 04:52:04 pm
content: http://opencv.org

author: Kilrah
author_rank: Unknown
timestamp: August 13, 2016, 06:02:58 pm
content: https://www.adafruit.com/products/1906

author: helius
author_rank: Super Contributor
timestamp: August 13, 2016, 06:19:09 pm
content: The Kinect uses photon time-of-flight sensors to build a 3d point cloud. Having depth data makes object reconstruction easier, but the device itself does not do feature recognition.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 13, 2016, 06:57:06 pm
content: I am not sure I know what you mean by elegant. There are some pretty fundamental trades in object detection, and no real way around them that I know. Edge detection, for example, requires an absolute minimum of comparing two pixels (and performs poorly at that minimum level). So the only way to further reduce processing is to reduce pixel count. If you know a priori the size of the objects you wish to detect you can match the resolution to that size and reduce pixel count. Or you can reduce processing by only looking for changes around previously detected objects. That leads to a whole family of solutions that does intense processing occasionally with delta processing on the frames between. As you pointed out, reducing frame rate is an option.The on chip processing approaches mentioned above don't fundamentally change any of this, they merely apply custom hardware to part of the solution and reduce the size of the data channel heading downstream.None of these solutions works in a general case, but can work quite well in a well defined problem space. As an example the processing required to detect a red ball in a green field can be quite simple. Detecting a single, moving, known size and contrasting object in a grey scale image is also relatively easy and computationally achievable. Can you narrow down your objective to allow some form of simplification?

author: docmur
author_rank: Regular Contributor
timestamp: August 13, 2016, 07:16:43 pm
content: Thanks for all the input
Image processing in the 80s and 90s, Datacube story - Page 1
Forum section: electronics / projects

author: djerickson
author_rank: Regular Contributor
timestamp: November 26, 2022, 05:22:18 pm
content: Hi all,I was at Datacube for 17 years. We were the performance leader in image processing hardware for much of that time. I though people would be interested in seeing the technology we used to do massively parallel pipelined image processing. All obsolete and long gone now. Datacube closed the doors in 2005.To paraphrase CuriousMarc: When Digital Engineers roamed and ruled the earth.https://www.djerickson.com/datacubeCheers,Dave
Image Processing - Page 1
Forum section: electronics / projects

author: Strube09
author_rank: Regular Contributor
timestamp: January 06, 2011, 03:39:08 pm
content: Hello everyone,Can anyone point me to some reference material covering image processing? I would like to use and image sensor and a uController to scan an area and look for a particular shape and color. When the shape and color match it outputs a simple LED/Piezo signal. No need to actaully drive a display.Thanks,Strube

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 06, 2011, 08:28:01 pm
content: you are talking about one complete subject being taught/learnt/studied in higher education level. its a complex subject, so finding a proper book is my suggestion, here is one examplehttp://www.amazon.com/Digital-Image-Processing-Rafael-Gonzalez/dp/0201180758(type image processing book in google), that book is my random search, but i think will be good enough.

author: MrJulius
author_rank: Newbie
timestamp: January 06, 2011, 10:13:10 pm
content: http://www.elektor.com/products/books/robotics/computer-vision-uk.428878.lynkxComputer Vision Principles and Practices, I have this tucked away somewhere.If you have any questions I will try to answer them, I will just have to find the book first

author: DaveW
author_rank: Frequent Contributor
timestamp: January 06, 2011, 11:09:19 pm
content: This was the recommended text for the uni course I did, was a good book and still use it myself every now and thenhttp://www.amazon.co.uk/Image-Processing-Fundamentals-Maria-Petrou/dp/0471998834/ref=sr_1_1?ie=UTF8&qid=1294355242&sr=8-1
Image sensor for card reader - Page 1
Forum section: electronics / projects

author: gaminn
author_rank: Frequent Contributor
timestamp: October 04, 2016, 07:26:10 pm
content: Hi,I'm thinking about designing scanner which will take color picture of credit card sized cards from both sides. Entire device must have max 3 inches in height, 5 inches width and depth. It will be low quantity commercial product (300 pcs/year).Do you know any low cost image sensor that would fit this application? I searched color linear image sensors but it seems they are hard to buy in small quantity and required size.

author: nctnico
author_rank: Super Contributor
timestamp: October 05, 2016, 01:56:44 am
content: With those size constraints you should have enough room for some mirrors and use a regular camera (module) as a sensor.
image sensor - Page 1
Forum section: electronics / projects

author: lucius_O_maximus
author_rank: Newbie
timestamp: March 21, 2013, 10:17:19 pm
content: Hi everyone,im looking for image sensors that work in infra-red , UV and eventually x-ray.If i could have a link of manufacturers that would be awesomethanks u all

author: timbos
author_rank: Contributor
timestamp: March 24, 2013, 03:50:45 pm
content: Any old CCD sensor will work in the IR up to about 1.1µm -- you might need to take its IR cut filter off though. Beyond that, you're into more exotic semiconductors which are expensive and less-easy to get hold of.Don't know much about what's available at the other end of the spectrum.
Impact of exceeding maximum Drain-Source Voltage on a 2N7002BK MOSFET - Page 1
Forum section: electronics / projects

author: MixedSignalSystems
author_rank: Contributor
timestamp: February 15, 2019, 05:52:32 pm
content: I've had a bit of a project SNAFU with the enable circuit for a DC-DC regulatorI'm using a 2N7002BK N-Channel MOSFET with a 100kOhm pull-up resistor connected to the MOSFET drain pin. The MOSFET source pin is connected to ground.Control signal (on MOSFET gate) goes high -> MOSFET is enabled -> DC-DC Regulator enable pin (on MOSFET drain) goes low ... SimpleThe pull-up resistor connects to the regulator input supply voltage. I've just realised that the supply can run up to 100V (rather than the 50V that I had previously assumed). The regulator can handle this but I'm not sure about the FET.The Vds(max) on the 2N7002BK is 60V.So, the 2N7002BK Vds could be ~100V, i.e. much greater than the 60V limit. The 100kOhm resistor will limit the current through the FET to the point where thermal effects of my mistake should not be problematic.Are there any other voltage related effects that I should be aware of? Require consideration?The board works but I'm worried about reliability. Is the FET going to fail early due to the excessive drain-source voltage?Happy to hear people's thoughts or references for me to read, etc.Thanks all.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 15, 2019, 06:43:56 pm
content: I would worry about progressive damage effects in avalanche, but if it's not overheating it's probably fine, at least for a good while.I wouldn't have a problem running prototypes that way; I'd be leery of sending it out to customers though. I would shop for a suitably rated replacement for the next run.Tim

author: anovickis
author_rank: Contributor
timestamp: February 15, 2019, 07:29:29 pm
content: Eventually you will poke holes in it, and it will stay conductingHow long exactly that takes is not easily known or an answer you should attempt to discover

author: MixedSignalSystems
author_rank: Contributor
timestamp: February 16, 2019, 12:33:59 am
content: Thanks Tim.That is helpful. I'll remove the FET on the prototypes and leave the regulator running all the time.Its a SOT23 package so finding a replacement should be doable.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 16, 2019, 12:39:15 am
content: What's the threshold on the enable pin? You could use a zener diode to limit the voltage.
Impact of specifying IPC-A-610 on fabrication notes? - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: May 07, 2018, 02:23:26 pm
content: I've had issues in the past due to poor connections on SMD pads. Mostly with connectors. This is to the point where I'm looking at switching board houses.Now, with a test-run I had to add some additional solder to one of the connectors and requested moving from a 4mil stencil to a 6mil.I've been told by a colleague that I should be looking at specifying IPC-A-610 to ensure that assembly meets proper QA standards.Since the allotment of solder paste is determined by the stencil thickness, which is determined by the smallest feature size on the PCB. What would change in the assembly process by specifying this IPC standard? Is it just added cost to have someone who's completed the coarse to sign-off on it? Or are there actual process and assembly changes made by specifying this?

author: Gibson486
author_rank: Frequent Contributor
timestamp: May 10, 2018, 05:42:30 pm
content: Depends where you get the work done. Most of the quick turn assembly places I know will just use IPC class 2 standards (which is what the a majority of the people want) unless you say not too. It is just cheaper for them to assume and it is in their workflow so deviating from it will cause more money and harm. So, to answer your question, it probably will not make that big of a difference unless the shop you use does not pride themselves in high quality standards. In most cases, if you put something in your notes that conflicts, they will ask you about it.If you use a big shop, I can see how they would want to use class 1 standards. In that case, those notes matter a lot.
Impact of unstable filters (audio) - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: October 15, 2020, 12:55:04 am
content: I'm working with a product that has a failure mode where the TI biquad filter can output a high pitched tone. It's an extremely rare failure mode that tends to happen once a year. Thousands of units power cycled hundreds of thousands of times.I've been working with some TI application engineers. Now, it was found out that way we've been initializing the filter wasn't ideal and the code was cleaned up. However, we just don't have the number of hours or systems running the code to see if it has an impact or not. The question was raised about the coefficients used for the filter. Now, the filter coefficients are on the borderline between being stable and unstable.If the filter did become unstable, wouldn't the output of the filter still be reduced to zero if the input of the filter is zero? On one of the rare occurrences of the failure mode, I was able to disconnect the input. So no audio data was being sent. However, the output was still a sustained tone.Changing the coefficients is easy and there's no issue with it but I have doubts if it would have any impact on the failure mode.TI App Note:https://www.ti.com/lit/an/sbaa378a/sbaa378a.pdf

author: srb1954
author_rank: Super Contributor
timestamp: October 15, 2020, 01:21:02 am
content: Quote from: Pack34 on October 15, 2020, 12:55:04 amThe filter incorporates a digital IIR (infinite impulse response) filter so there is always a possibility of oscillations if the filter coefficients are chosen incorrectly or there are numerical calculation errors due to round-off errors or overflow errors. An IIR filter can oscillate even if there is no input unlike an FIR where the output will eventually die away if there is no input.It is a bit of a mystery that the failures occur randomly as you would expect a digital filter to perform consistently well or consistently badly.

author: Pack34
author_rank: Frequent Contributor
timestamp: October 15, 2020, 01:28:30 am
content: Quote from: srb1954 on October 15, 2020, 01:21:02 amThat's another point I had in the back of my head. If the filter coefficients were unstable it should occur much more consistently. I would assume we're configuring it incorrectly and some of the coefficients just wouldn't take when setting it up. The filter is even enabled when we were configuring it.
Impact on EMI due to test points placed on unpopulated side of PCB - Page 1
Forum section: electronics / projects

author: jabramo
author_rank: Regular Contributor
timestamp: October 22, 2024, 10:20:18 pm
content: Hi,I am designing a high volume production 4-layer PCBA with 2 EMI shielded switching power supply circuits. The customer and EMS require a test point on every net for 100% ICT coverage. Ideally all the test points would be located on the unpopulated bottom side of the PCB to allow for a high density power supply layout and reduced cost single sided ICT fixture.I am concerned about placing test point stubs that connect to the switching nodes with a via may have some negative impacts on the EMI performance of the board. I am not too concerned about the parasitic capacitance of the test points impacting the impedance of the nets as the switching frequency is 400khz. However I am worried that plunging the switching node down 4 layers to the test point stub on the bottom of the board which is not shielded like the top side may create an antenna and impact the radiated emissions performance.Does anyone have anyone have any experience with this or can point me to any good resources on this topic?Thank you

author: Salitronic
author_rank: Contributor
timestamp: October 22, 2024, 11:40:30 pm
content: The typical 1.5mm test point via stub would only start radiating at frequencies in the 10GHz+ range so I wouldn't expect these to be an issue for the power supply circuits you are describing.What you might want to be careful about is whether these multiple test points (together with other vias that you might have) are splitting and disruption the ground plane to a point where there is no good ground plane left under the power supply.

author: Tobias89
author_rank: Contributor
timestamp: October 23, 2024, 06:27:34 am
content: Double check with the EMS. From my experience, this is a typical starting requirement for ICT - 100% net coverage.However, each rule has an exceptions. A perfectly good coverage can be retained even if you omit some critical nets - you'll want your feedback net of the SMPS to be the smallest possible. If all other nets pass the ICT and FCT is good, then no one will care if the FB net didn't pass the ICT.The same goes for the parts of the RF path and similar.Just make sure you communicate the tradeoffs clearly with all stakeholders - that there is a good reason behind your concerns.
Impedance Analyzer design using the AD8302 - Page 1
Forum section: electronics / projects

author: ddsRV
author_rank: Newbie
timestamp: September 16, 2025, 12:10:34 am
content: Hi there,I’m using an AD8302 gain/phase detector in a simple divider setup to measure a quartz crystal. Right now I can log the raw VMAG and VPHS voltages vs frequency.What I’d like to end up with are analyzer-style plots such as:|Z|(f) (impedance magnitude vs frequency)G/B admittance curves (conductance & susceptance vs frequency)Basically, I want my sweeps (image 1) to look more like what you’d see on a Keysight 4294A(image 3) or in QCM literature(Image 2).Question: What’s the right formula pipeline to take VMAG/VPHS → impedance/admittance curves? Do I need to convert to a complex ratio first, or is there a simpler direct way?

author: Terry Bites
author_rank: Super Contributor
timestamp: September 18, 2025, 06:11:52 pm
content: 1 Buy a nano VNA and stop worrying. I'm still in the warm fuzzy stage of this new romance.2 Read up on how a VNA works.3https://hamprojects.wordpress.com/2016/02/21/hf-arduino-vna-english-version/4https://hackaday.com/tag/ad8302Yep, buy a nano........
Impedance control on LISN power output - Page 1
Forum section: electronics / projects

author: jmw
author_rank: Frequent Contributor
timestamp: December 21, 2019, 10:19:58 pm
content: A 50u/50 ohm DC LISN should look like this:It's supposed to present a 50 ohm || 50 uH impedance looking in from the output, i.e. Z_in should be a flat 50 ohm above 160 kHz. How is this meaningful in practice when the LISN is connected to the DUT with straight wire that adds series inductance? The examples of LISN either have banana-style terminals (DC) or mains plugs (AC) so no impedance control. Similarly, the connection from the bulkhead power ports to the LISN board doesn't appear to be impedance controlled either.

author: bjbb
author_rank: Contributor
timestamp: December 23, 2019, 07:44:41 pm
content: CISPR16-1-2 is the basic guidance for ISNs. Note the frequency curves for max and min Z; that is the characteristics of your particular ISN is dependent on the data generated by your calibration contractor or however you get your calibration plots.Some generic EMC standards have both normative and 'suggested' ISN connections; and some do not. In any case, I have not seen 'banana' connectors for the AWM output on anything made in last 10 or 15 years.Power wiring out of the ISN and into the UUT, at frequencies intended for conducted emissions measurements of appliances, should be representative of the intended end-use.Typically, mains impedance of the in-line components are much higher than that added by conductors for appliances and IT equipment. Power into the ISN is generally assumed to be per a narrow range of Z.

author: jmw
author_rank: Frequent Contributor
timestamp: December 23, 2019, 07:51:43 pm
content: I found this article (https://incompliancemag.com/article/topology-and-characterization-of-a-dc-line-impedance-stabilization-network/) with pictures and it looks like they measured the output port impedance by running coax from a VNA up to a custom-job adapter that is as small as possible. For a banana plug style output, a similar construction could be an off-the-shelf BNC-to-banana adapter. I'll also read about what the standards say about suggested connections..

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 23, 2019, 08:20:45 pm
content: The LISN-to-EUT wires need to be 50 ohms (or 100 ohms differential, in the mains case), yes.Alternately, everything after the LISN is considered EUT. It is a good idea to provide a standard cable length with the product (and recommend the same in the manual), and test with that.Tim

author: coppercone2
author_rank: Super Contributor
timestamp: December 25, 2019, 07:44:11 pm
content: and a better idea to make sure it works with whatever plugs into it because you know that will happenif we lived in a perfect 50uH electrical world. A sweepable ISN inductance would be interestingperhaps since the coils are usually split into segments, relays could be added to short out segments to change it?
Impedance controlled traces with vias for HDMI ADV7511 - Page 1
Forum section: electronics / projects

author: HasanSyr
author_rank: Contributor
timestamp: May 07, 2025, 09:49:53 am
content: I have these HDMI 1/2 parallel signals coming from the FPGA SOM down to a dev board on both sides of the board-to-board connector (16 bit parallel YUV/RGB lines NOT the TMDS differential pairs). If both HDMI connectors are on one side how am I supposed to route to the other side of the BTB connector? All traces are monostrip impedance controlled. Do I need to calculate the trace width for every layer I route on? Can I just via down? Do I go to the last signal layer or the closest one? I'm using JLCPCB so I can't use blind vias.How much does it affect the signal, it's fairly fast at ~150 MHz?Im most likely going to use the following stackup:sig/gnd/sig/pwr/gnd/sigThanks in advance

author: bostonman
author_rank: Super Contributor
timestamp: May 08, 2025, 12:35:28 am
content: I'm uncertain, however, I'd say all the traces need to be equal and vias would need to equal the same volume.My method of thinking: if you have 1/2" water pipe, you wouldn't go to a 1/4" coupling, back to 1/2", etc... so I imagine all traces and vias would need to be equal.
Impedance looks fine but 3.3V is dropping to 0.9V - Page 1
Forum section: electronics / projects

author: muthukural001
author_rank: Regular Contributor
timestamp: February 02, 2020, 06:43:07 am
content: Hello All,In my board, 3.3V rail going down 0.9V. I have one more board that is working fine and impedance of 3.3V on both the boards is same. I am wondering which is causing the voltage drop for 3.3V rail.Thanks and Regards,Muthu

author: aix
author_rank: Regular Contributor
timestamp: February 02, 2020, 06:56:26 am
content: Maybe this is useful?

author: moffy
author_rank: Super Contributor
timestamp: February 02, 2020, 08:59:20 am
content: You need to measure the current load. Active devices will only switch on above certain voltages. Feel the components on the board, if one is realy hot then have a look.

author: muthukural001
author_rank: Regular Contributor
timestamp: February 03, 2020, 04:24:56 pm
content: Hi,I probed 3.3V rail with the oscilloscope and attached the same. As we can see, it is not dropping to 0.9V but going between 3.3V and 2.4V. Also,I have noticed a strange behaviour in my board, I removed the 3.3V sense resistor and connected my multimeter in 10A current mode across the sense resistor. With this setup, I do not see anything like in the image attached, it was a stable 3.3V. The sense resistor is just 20mili ohms and I hav no idea why my board is not working as expected with the sense resistor connected instead of multimeter in current mode. Is there any logic behind this?Thanks,Muthu

author: thinkfat
author_rank: Unknown
timestamp: February 03, 2020, 08:12:10 pm
content: What is that sense resistor doing?And how do you think people here will be able to help you if you keep information like this for yourself?

author: moffy
author_rank: Super Contributor
timestamp: February 05, 2020, 08:05:08 am
content: The multimeter is just shorting out the sense resistor. So 1: Bad sense resistor or 2: Bad solder joint to sense resistor or 3: partial break in track. My money is on 2.

author: Prehistoricman
author_rank: Regular Contributor
timestamp: February 05, 2020, 11:42:43 am
content: Did you use the milliamps range on your meter before adding the sense resistor? This range has a fair amount of resistance and could cause that much voltage drop. The 10A range is basically a short-circuit.
Impedance sweep on a coil - Page 1
Forum section: electronics / projects

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: August 24, 2019, 04:16:17 pm
content: I'd like to plot the impedance vs frequency graph of a coil using my function generator set to sweep from 20 Hz to 20 KHz sine waves and use my graphical multimeter to record the resistance over time.That being said, I haven't been able to get even one resistance measurement at a random frequency (10 KHz, 1V RMS) since the resistance is in the mega ohms.What am I doing wrong here? Can this not be done this way?

author: duak
author_rank: Super Contributor
timestamp: August 24, 2019, 05:41:04 pm
content: When you say resistance of the coil, do you mean the DC resistance or do you mean the AC reactance or impedance?If you want the AC impedance you have to measure the current flowing through the coil. If the meter does not have an AC current input this can be done by measuring the AC voltage across a resistor in series with the coil. Even better is to use a transimpedance amplifier that has a low input impedance input and produces a voltage out proportional to the input current. Once you have the current, you can determine the impedance because Z = V/I where V is the voltage across the coil and I is the current through the coil.What is the make and model of your graphing meter?

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: August 24, 2019, 05:55:18 pm
content: Quote from: duak on August 24, 2019, 05:41:04 pmYes surely I meant the Impedance of the coil as resistance is the DC equivalent.I have a Keithley DMM6500. I can digitize current so that shouldn't be an issue.Thanks!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 24, 2019, 08:17:12 pm
content: The most basic circuit, assumes a constant 50 ohm source resistance and constant amplitude from the generator.Connect the generator directly to the coil. Tee this connection off to the voltmeter. Sweep frequency while measuring voltage.You don't measure phase this way, and must reconstruct it from a curve fit, or the Kramers-Kronig relations.This is a shunt method, and works best for impedances less than 25 ohms.You can also do a series method, where the coil is in series between source and load; in that case, replace the tee with a coupler (tie the grounds with a much lower impedance, e.g., a metal box with two connectors bolted into it) and connect the coil between the center conductors. Terminate the voltmeter end so that the system is 50 ohms all the way through. This works best for impedances more than 100 ohms.You can measure phase this way, but you need a reflectance bridge. A VNA (vector network analyzer) contains one of these each for both source and load, and measures phase (hence "vector"). This also lets you determine any line-to-ground impedance the coil may have (which can be substantial when high impedances are being measured).Tim
Impedance/LCR Circuit for |Z| around 6k with around 12-17kHZ - Page 1
Forum section: electronics / projects

author: skylape
author_rank: Newbie
timestamp: September 11, 2020, 03:04:17 am
content: For my specific need, I would like to design an impedance meter for measuring application around magnitude of 6k and at frequency around 15kHz. That being said, Im not sure where to start. Is there an available IC that can do this or should I design this by myself? If so, where should I start.

author: MasterT
author_rank: Frequent Contributor
timestamp: September 11, 2020, 04:58:33 am
content: 1 MSPS, 12-Bit ImpedanceConverter, Network AnalyzerAD5933
Implement a random state for flip-flops - Page 1
Forum section: electronics / projects

author: renz.bagaporo
author_rank: Newbie
timestamp: October 22, 2013, 04:49:09 am
content: Hi!So I want to make a simple memory game. I have 8 flip-flops, each storing the information whether an LED is on or off. How can I implement a random state generator for the flip flops?Thank you very much.

author: Balaur
author_rank: Unknown
timestamp: October 22, 2013, 06:03:43 am
content: LFSRWith 8 flip-flops and 3 2-inputs XOR gates you get a nice pseudo-random number.

author: Bertho
author_rank: Regular Contributor
timestamp: October 22, 2013, 08:33:02 am
content: If you want a real random start, then you can use a serial-in-parallel-out shift register where you input a random signal at the serial input, clock it to shift in and when needed, transfer the parallel data to the flip-flops.A hardware random generator can be created with a bipolar transistor's BE barrier in reverse at a voltage which surpasses the breakdown point.

author: renz.bagaporo
author_rank: Newbie
timestamp: October 25, 2013, 10:33:56 pm
content: Thanks for all of your reply !
Implement Battery charging algorithm along with MPPT algorithm to charge battery - Page 1
Forum section: electronics / projects

author: Siddhat
author_rank: Regular Contributor
timestamp: April 10, 2020, 12:51:34 pm
content: Hey, hope everyone is doing fine!I need to charge a lead-acid battery from a solar panel. In order to extract the maximum power from the solar panel, I have already implemented the MPPT algorithm (written the code) in a buck-boost converter and simulated the circuit and the algorithm in MATLAB. Attached below is the schematic.But, I want to charge a lead-acid battery at the output of the buck-boost converter. I know that I have to implement a battery charging algorithm that has 3 or 4 stages. But I am unable to do so.The problem that could not figure out is how do I implement the battery charging algorithm along with the MPPT algorithm with a single stage of a buck-boost converter??
Implementation for 5V tolerance on 3.3V MCU GPIO? - Page 1
Forum section: electronics / projects

author: bxh
author_rank: Contributor
timestamp: January 08, 2016, 02:24:42 am
content: I've seen several IO pins on some devices which are 5V tolerant, and never really thought too much about it until now..I have a rough understanding of how diodes are commonly used to protect IO pins from over/undervoltage, but how is 5V tolerance actually implemented without having too much of an effect on the capabilities of the IO pins?If for some reason I wanted to make one of the 3.3V GPIO pins (on a development board let's say) 5V tolerant using external components, how could/should I achieve it?

author: Fungus
author_rank: Super Contributor
timestamp: January 08, 2016, 02:32:09 am
content: Put a resistor in front of the clamping diode to limit the current that can pass through that diode to something it can handle.If the pin needs high-current output capability then you need an extra MOSFET to bypass the resistor when the pin is in output mode.

author: station240
author_rank: Unknown
timestamp: January 08, 2016, 05:50:33 am
content: I did find this page on how to interface the RPi with 5V IO devices.http://tansi.info/rp/interfacing5v.htmlPretty much sums up the various circuits I'd use anyway.Of note are the sparkfun level converters, remember their stuff is opens source hardware, so you can use it in your own designs.If you're going to make an entire 8 bit port 5V tolerant, there are proper level converter chips that would be more practical to solder in.

author: chicken
author_rank: Frequent Contributor
timestamp: January 08, 2016, 06:27:35 am
content: Here's an app note from TI that discusses several options to implement level conversion for 3.3V MCUs:http://www.ti.com/lit/an/slaa148/slaa148.pdf
Implementation of a charge level indicator - Page 1
Forum section: electronics / projects

author: Vulpecula
author_rank: Newbie
timestamp: December 19, 2022, 03:53:53 pm
content: Hello all,I turn to you because I have a problem that I lack a little experience to solve. Maybe I can get some ideas here.Context is that I have a battery powered system with a microcontroller (Microchip ATSAME51). The charging of the 2S LiPo battery is done by USB PD and specifically implemented by aTexas Instruments BQ25792charge controller behind aTexas Instruments TPS25750USB PD controller. I want to add a battery indicator to the system, but don't know exactly how best to implement this yet.My idea is to have four LEDs, with one LED representing 25% of the total capacity at a time. At 0-25% one LED lights up, at 0-50% two LEDs light up and so on. Maybe with a flashing LED for the case that an area was not yet completely loaded. In general, this is a display like you know it from powerbanks and the like. I hope you understand what I mean.One possibility for the realization of my plan would be not to switch off the system completely (that is what I am doing right now), but to set the microcontroller in some kind of low-power mode. The charging of the battery ist signaled by the charge controller via an output (the "STAT" pin), which could then trigger an interrupt and cause the microcontroller to read out the state of charge of the battery from the charge controller via I2C. However, I'm not quite sure what that would do to the (idle) power consumption of the system.But maybe someone knows other/better possibilities to implement something like this. Are there possibly already ready ICs with such a logic?Thanks a lotVulpecula

author: coromonadalix
author_rank: Super Contributor
timestamp: December 19, 2022, 04:30:07 pm
content: you could use an lm3914 linear led driver ?? with the right values, it could be used as an battery gauge ?? very cheap and simple to implementsomething like thishttps://www.ebay.com/itm/265185004806?you have 3 models the lm3914, lm3915, lm3916 it varies between linear and logarithmic values on the leds, you have dot mode or led ramp etc .....

author: kripton2035
author_rank: Super Contributor
timestamp: December 19, 2022, 05:42:15 pm
content: use a HM1160 chip. does all what you need in a tiny package.http://aitendo3.sakura.ne.jp/aitendo_data/product_img/ic/power/HM1160/HM1160-E.pdfavailable at least at aliexpress :https://www.aliexpress.com/item/1005003135937876.html
Implementing a Conformal Coat Machine for PCBs - Page 1
Forum section: electronics / projects

author: desertjay
author_rank: Newbie
timestamp: July 30, 2025, 01:00:15 am
content: I have been tasked by my company to automate the conformal coat process. Right now we spray in a spray booth with a spray gun and cover any connectors needed to be covered. I think this is optimal but safety from fumes is the biggest concern. The enclosed machine will make it safer. It has been a nightmare trying to get this thing ready for production. I mean we are trying to spray a material that tacks in 10/15 minutes through tiny nozzles and connection points. The maintenance and cleaning has been crazy and will continue to be. The PCB I am programming for takes about 15 minutes to run (very large board) This causes conformal coat to start tacking on the tip of the nozzle. It’s been a year since we started this project. The quality is also much lower compared to the current method (a lot of process indicators like small bubbles and wet lines). The higher ups think this machine fell from heaven when it feels so inefficient to me and like a terrible purchase.I am curious if anyone has any experience with conformal coat machines and any tips or tricks??

author: moffy
author_rank: Super Contributor
timestamp: July 30, 2025, 02:10:23 am
content: I would suggest a low pressure degassing stage before it gets tacky to remove bubbles from the conformal coating.
Implementing a USB C Rp / Rd switch (with CH32V203) - Page 1
Forum section: electronics / projects

author: eigenvektor
author_rank: Contributor
timestamp: April 12, 2023, 08:03:14 am
content: Hi all,I'd like to implement an Rp / Rd switch as described byhttps://www.ti.com/lit/wp/slyy109b/slyy109b.pdfin figure 5 and 6.I'm making a split keyboard with no battery to worry about.Basically just needs to switch between connecting the cc pins to a Rd or Rp resistor, with the default (no power) state being connected to Rd. Connection sensing would be nice but is optional.What would be the easiest way to implement this? I feel like the microcontroller I'm using should have this functionality integrated as it advertises "USB Host / Device" (CH32V203) but I can't find any info in the datasheet and all the dev boards just pull the CC pins to ground on all USB ports.One option is using a CC controller by TI but those are 1usd @ 99 units and seem very overkill.Another is implementing it with transistors, but I'm not entirely sure what the best way would be. Here's one I found in a knowledge base article on the infineon forum (https://community.infineon.com/t5/Knowledge-Base-Articles/DEAD-BATTERY-CHARGING-IMPLEMENTATION-IN-CCG1-SOLUTIONS-KBA97273/ta-p/259059)Are there any recommendations? I can't seem to find an "official" implementation.

author: eigenvektor
author_rank: Contributor
timestamp: April 25, 2023, 07:02:25 am
content: I'm not sure if I have an error in my thinking, but wouldn't the attached solution work?When the ic pin is in the default (floating) state, the cc pin is pulled down to ground over Rd (5.1k) and identifies as a UFP. The ic pin can be used to monitor voltage on the cc line and detect current capability of the DFP.When the ic pin is driven high it identifies as a DFP. Driven to 3.3 V, the voltage on the cc line is about 1.61 V and advertises current capability of 3A, when it is driven to 0.85 V the voltage on the cc line is 0.41 V and advertises a current capability of 0.9 A.
Implementing an interchangeable RS232 pinout - Page 1
Forum section: electronics / projects

author: michaelym
author_rank: Regular Contributor
timestamp: December 16, 2012, 03:42:55 pm
content: I need to figure out how to use two RS232 pinout variations with the same RJ45 connector and cable.I tried Googling for an IC that will do the job but I don't know what keywords to look for.The pinout can be set by the software and I don't need my circuit to detect it.Any ideas?

author: david77
author_rank: Frequent Contributor
timestamp: December 16, 2012, 04:07:22 pm
content: Maybe analog switches or multiplexers, CD4066 or 4051?

author: AndyC_772
author_rank: Super Contributor
timestamp: December 16, 2012, 06:10:18 pm
content: The easiest way may be to use two RS232 transceivers, each wired according to one of your required pinouts, and then to enable only one or the other. You'll need a transceiver which can have its output turned off and made high impedance.
Implementing Bluetooth SPP on a budget PCB - Page 1
Forum section: electronics / projects

author: cluelessjoe
author_rank: Newbie
timestamp: July 11, 2022, 11:00:04 am
content: Hi, for my final project I am using an STM32 MCU to gather analog information and saving them on an SD card. I also need to send this data wirelessly via Bluetooth. I am considering using Bluetooth SPP since I am quite familiar with UART and serial and for my use case simplicity is more important than an elegant design.I have looked around to find a simple Bluetooth SPP solution around Digi-Key and Mouser however the solutions I found were overkill MCUs with Bluetooth capability. I am quite familiar with STM32 and since I do not currently have access to STM32WB series chips I have to find another way. I thought about using a barebones HC-06 board but I believe that's really janky even for this project.I am currently looking at IS1678 from Microchip since it does support Bluetooth SPP but I cannot find stock anywhere.I would really appreciate any opinion/advice regarding possible Bluetooth solutions. What IC/module should I use?Thank you so much for your help guys <3
Implementing Stereo Volume Control - Page 1
Forum section: electronics / projects

author: knapik
author_rank: Regular Contributor
timestamp: March 28, 2020, 06:46:09 am
content: I'm planning to use an ISSI IS31AP2110 Class-D amplifier with line level audio input, but am kind of stuck in regards to how to implement volume control. The easiest way I can think of is with a dual gang potentiometer, but I want to try and avoid big, clunky through hole parts. I thought about using digital potentiometers, but found out they're not really suitable for AC coupled inputs.Any opinions or ideas how I can do this? I'm a bit out of ideas.

author: Messtechniker
author_rank: Frequent Contributor
timestamp: March 28, 2020, 06:50:35 am
content: Have a look at the PGA2311 chip and its brothers.

author: knapik
author_rank: Regular Contributor
timestamp: March 28, 2020, 07:03:55 am
content: Quote from: Messtechniker on March 28, 2020, 06:50:35 amLooks pretty fancy and easy to use, but its ~10x the price of the amplifier itself, so I'll take a look at other similar ICs

author: knapik
author_rank: Regular Contributor
timestamp: March 28, 2020, 07:33:17 am
content: The LM1972 will probably do the job, so thanks for the help there.

author: SiliconWizard
author_rank: Super Contributor
timestamp: March 28, 2020, 04:08:09 pm
content: Quote from: knapik on March 28, 2020, 07:03:55 amI've used similar PGA2320 in the past - very good stuff. But yes, a bit pricy.There's also the CS3310 in a similar vein. Not cheap either.The LM1972 looks adequate if you're not after ultra-low distortion figures (but it looks already not bad at all, and getting better wouldn't make sense using an IS31AP2110 anyway). One extra thing you get with the 2 above is gain and not just attenuation, but even that you could add for cheap if it were needed here.

author: glentek
author_rank: Regular Contributor
timestamp: March 29, 2020, 10:35:52 pm
content: I use the m62429 in my car amplifier.http://nice.kaze.com/M62429.pdfEasily controlled by arduino. You can buy a prebuilt module from Sure on Aliexpress or ebay, or the chip itself for under $2http://store3.sure-electronics.com/aa-aa11117

author: knapik
author_rank: Regular Contributor
timestamp: March 29, 2020, 10:48:35 pm
content: I'll keep that in mind for any future revisions/projects. Does seem about 1/2 the price of the lm1972 and it includes the buffers on the IC.
Implications for outdated UL reports  - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: December 18, 2020, 10:50:42 pm
content: Suppose you make a medical device and have multiple factories. What are the consequences if a factory is not added to the safety report prior to the first article being produced? It is certified at the other locations

author: m k
author_rank: Super Contributor
timestamp: December 19, 2020, 12:28:37 pm
content: Before or after accident?If latter then don't worry, your insurance company will inform you.
Implications of Slow or Floating CMOS Inputs.... Great read... - Page 1
Forum section: electronics / projects

author: Smokey
author_rank: Super Contributor
timestamp: March 27, 2014, 07:26:29 pm
content: No matter how much stuff you think you know, there is always something super fundamental that you don't know that will make your widget blow up."Implications of Slow or Floating CMOS Inputs"http://www.ti.com/lit/an/scba004c/scba004c.pdf
Importing a component into MultiSim 13.0 - Page 1
Forum section: electronics / projects

author: MCPorche
author_rank: Contributor
timestamp: February 25, 2015, 08:52:02 pm
content: I downloaded a project file that someone created with MultiSim 10.0. The circuit includes an LM317 Adjustable Voltage Regulator.This component is not included with the library that comes with MultiSim 13.0. I tried to copy the Spice model data, and create a new component. However, it doesn't work as it should. I made a circuit out of the one from the project I downloaded, and with the resistors I used, I get 3.317V. When I replace it with the component I created, I end up with 11.996V.Is there some way to take a component from a circuit, and save it into your database? Or could someone maybe point me in a direction to troubleshoot why the component I created didn't work?Thanks.Monte
Importing a frequency domain plot into AWG? - Page 1
Forum section: electronics / projects

author: Mark
author_rank: Frequent Contributor
timestamp: October 15, 2021, 11:14:24 am
content: I can record a time-domain waveform and upload it to an AWG to recreate the signal.If I have a frequency-domain plot from a spectrum analyser, can I use that to generate an AWG signal with the same harmonic content?Ideally I would want to automate the process, not manually enter every peak on the frequency plot.Thnak you.Mark.

author: jeremy
author_rank: Super Contributor
timestamp: October 15, 2021, 11:24:21 am
content: The issue is that a time domain plot is not equal to a frequency domain plot on a spectrum analyser; the spectrum analyser does not capture the signal phase.But I don’t see why you couldn’t just do an inverse Fourier transform and then use that (assuming the AWG has enough bandwidth); the time domain signal will be all messed up because you will need to make up the phase data though.
Impossible to find a 120VAC to 12VAC adapter? - Page 1
Forum section: electronics / projects

author: SharpEars
author_rank: Unknown
timestamp: November 08, 2016, 05:03:07 pm
content: I am trying to find a plug in adapter that takes in 120 VAC and produces an output of 12 VAC with at least 4A of output current. I tried search AliExpress but all the hits are for adapters that produce 21 V DC. Is there anything available that can take in 120 VAC and produce 12 VAC with at least 4A of output?

author: Ian.M
author_rank: Super Contributor
timestamp: November 08, 2016, 05:17:27 pm
content: https://www.altex.com/MG-Electronics-12VAC-50VA-Class-II-Power-Supply-MGT-1250-P155702.aspxKeywords: 120V 12VAC 50VA

author: SharpEars
author_rank: Unknown
timestamp: November 08, 2016, 08:35:36 pm
content: Quote from: Ian.M on November 08, 2016, 05:17:27 pmThanks!
Improve a magnetic alarm for the door - Page 1
Forum section: electronics / projects

author: Micky
author_rank: Newbie
timestamp: January 12, 2016, 09:57:38 pm
content: Hi,I've bought this simple "alarm" for a door:Which is internally provided with a reed switch; but when the door is closed, and so the magnet will be placed again near to the reed switch, the internal buzzer of the alarm will stop to ringing. I'd like to extend the ringing time of the buzzer: the most simple idea which I have in my mind is to connect a very big capacitor (or a batch of capacitors) in parallel with the batteries of the alarm: would be a good idea? Since the batteries are simple button cells, if the alarm would be activated indefinitely, the batteries will discharge quickly. So would be a good compromise a ringing time of about ten/fifteen minutes: that would be a viable solution or someone could suggest me a better and smarter idea? I can also consider to attach better batteries (eg Eneloop).Kind regards.

author: jeroen79
author_rank: Frequent Contributor
timestamp: January 12, 2016, 10:15:32 pm
content: You could use a monostable 555 timer.The timer would be triggered with the reedswitch and it's output would control a transistor in place of the reedswitch.