hybridfree/eevblog-posts huggingface dataset:
Elongated plastic washer for a test jig - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: October 27, 2015, 08:35:00 pm
content: I'm putting together a test jig with some pogo pins and was hoping to secure it down during the test. I know I've seen this type of hardware before but I'm having trouble finding it.Basically what I'm looking for is an elongated plastic washer. A plastic washer that has a slot instead of a circle cutout. There has to be another name for something like this because so far all I've found were toilet seats.The end goal is to have something that could sit on top of a spacer and swing or slide in-and-out to retain the board-under-test in contact with the pins while the test is being run. I could probably makeshift something out of some scrap plastic or wood but I wanted to make this jig look professional.Any ideas?

author: lincoln
author_rank: Regular Contributor
timestamp: October 27, 2015, 10:39:22 pm
content: Hmm, Do you mean like a slot (ref A) for adjustment, or like a key hole (ref B) for easy installation ect?Link

author: Paul Price
author_rank: Super Contributor
timestamp: October 27, 2015, 10:45:46 pm
content: Obtain a circle washer and cut into the circle to create the slot.

author: Pack34
author_rank: Frequent Contributor
timestamp: October 27, 2015, 11:59:55 pm
content: Quote from: lincoln on October 27, 2015, 10:39:22 pmA. The one for adjustment.

author: langwadt
author_rank: Super Contributor
timestamp: October 28, 2015, 12:25:34 am
content: Quote from: Pack34 on October 27, 2015, 08:35:00 pmany old washer with an offset hole, just turn it to retain

author: calzap
author_rank: Frequent Contributor
timestamp: October 28, 2015, 02:19:04 am
content: Get a set of cork borers. See the pic. Essential for anyone who wants to make custom soft washers. Available from Amazon, eBay and any scientific supply house. Works for rubber, leather, and soft plastics (vinyl, polyethylene, polypropylene, Teflon, etc.). You can do the big cut first. Then if you need a rectangular slot, use a utility knife or scalpel to cut it. If you need keyhole slots or slots with rounded ends, use smaller cork borers plus a utility knife. If you need to make a lot of soft washers, you can buy a more expensive cork-boring machine that has a crank handle or motor.Mike in California

author: DTJ
author_rank: Super Contributor
timestamp: October 28, 2015, 03:09:06 am
content: I've used the little fingers of FR4 that come attached to panels of PCBs for exactly what you are talking about.They insulate, they are springy and they were free. I mounted them using M3 or M4 brass hex pillars.Alternately check out your local big hardware for any drawer or door clicky type fixings that could be adapted.
elr psu wo. - Page 1
Forum section: electronics / projects

author: m3vuv
author_rank: Super Contributor
timestamp: June 25, 2021, 10:41:28 am
content: hi all im building this psu from an old magazine issue i found,the issue i have is after building it, c9 exploded and r23 fried,is there an issue with b1 ie bridge rectifier as it seems to have strange pinouts,is it a ballsup?,cheers in advance.

author: m3vuv
author_rank: Super Contributor
timestamp: June 25, 2021, 10:49:51 pm
content: as in the pinouts of br1,seems wrong to me?

author: m3vuv
author_rank: Super Contributor
timestamp: June 25, 2021, 10:52:01 pm
content: b1 sorry seems to have weird pinouts,is nthat the issue?

author: xavier60
author_rank: Super Contributor
timestamp: June 25, 2021, 11:13:34 pm
content: BR1's pinout is unusual,https://www.bing.com/images/search?q=inline+bridge+rectifier&form=HDRSC2&first=1&tsc=ImageBasicHoverAdded: If you have a round type, the pins might be able to be bent to the correct position.

author: m3vuv
author_rank: Super Contributor
timestamp: June 26, 2021, 01:18:20 am
content: thatsw exactlly my issue,ie is it a missprint,i bent the legs of a bridge rectifier to natch the silkscreen but its wierd as to why the cap blewup,almost like the polarity was reversed ?

author: xavier60
author_rank: Super Contributor
timestamp: June 26, 2021, 02:17:55 am
content: I can't see a link between BR1 being incorrectly wired and the other damage.Harrison/floating designs can be tricky to make sense of.Replace R23 with something higher like 470 ohms for now.Extra: mains to the power transformer should be removed for initial tests.Check the control rails and the reference voltage.The outputs of both opamps should be high.

author: m3vuv
author_rank: Super Contributor
timestamp: June 26, 2021, 08:00:26 am
content: this is the only datasheet i can find for b1,should both center legs both go to ac?,i wonder if the pdf is a missprint?,would that cause the magic smoke?.

author: m3vuv
author_rank: Super Contributor
timestamp: June 26, 2021, 08:11:06 am
content: also forgot to mention the small transformer powering b1 got hot as well,as if it was shorted.

author: xavier60
author_rank: Super Contributor
timestamp: June 26, 2021, 08:35:58 am
content: Quote from: m3vuv on June 26, 2021, 08:00:26 amYes, if that's what you have.This shows what suits the PCB,https://www.ebay.es/i/142969826800Show us a photo of what you have there.

author: xavier60
author_rank: Super Contributor
timestamp: June 26, 2021, 11:06:20 pm
content: Or The orientation of the internal diodes can be checked with a DMM on Diode test, better if it makes diode beeps.
Elusive OR gate - Page 1
Forum section: electronics / projects

author: Zom-B
author_rank: Regular Contributor
timestamp: January 22, 2017, 09:18:17 am
content: What does NXP'sElusive OR gatedo?

author: amyk
author_rank: Super Contributor
timestamp: January 22, 2017, 09:24:10 am
content: It's an OR gate, but it's hard to get a straight answer out of it.

author: tautech
author_rank: Super Contributor
timestamp: January 22, 2017, 09:29:20 am
content: Quote from: Zom-B on January 22, 2017, 09:18:17 amUse this to see how it functions and how it might suit your needs.....or not:https://tams.informatik.uni-hamburg.de/applets/hades/webdemos/10-gates/00-gates/xor.html

author: tautech
author_rank: Super Contributor
timestamp: January 22, 2017, 09:30:31 am
content: Quote from: amyk on January 22, 2017, 09:24:10 amJust like some woman I know.

author: Gyro
author_rank: Super Contributor
timestamp: January 22, 2017, 10:45:20 am
content: Must be hell trying to keep track of their stock!

author: MK14
author_rank: Super Contributor
timestamp: January 22, 2017, 12:30:25 pm
content: Quote from: Zom-B on January 22, 2017, 09:18:17 amIt's a member of this type of logicFAMILY:

author: Luminax
author_rank: Regular Contributor
timestamp: January 23, 2017, 05:03:20 am
content: Sounds like a Neither Nor gate

author: edpalmer42
author_rank: Super Contributor
timestamp: January 23, 2017, 05:19:10 am
content: Isn't it related to the maybe gate or the sometimes gate?Another reason it's elusive is because the minimum order quantity is 9000!

author: obiwanjacobi
author_rank: Super Contributor
timestamp: January 23, 2017, 08:25:32 am
content: Is that the Heisenberg or Schrödinger version?

author: Fulcrum
author_rank: Regular Contributor
timestamp: January 23, 2017, 08:46:53 am
content: A basic building block of the quantum computer
email replies from Android phones loose html format - Anyone seen this? - Page 1
Forum section: electronics / projects

author: AndersJ
author_rank: Frequent Contributor
timestamp: February 12, 2018, 01:30:50 am
content: Scenario:* Compose html email, with embedded picture, bullets, colors, fonts, etc.* Send to receiver, that responds on a Android phone.* When response comes back, all formatting is gone.If the response is written on a ”normal” PC the formatting is preserved.Has anyone seen this?Any explanation?
embedded µC with voice messages - Page 1
Forum section: electronics / projects

author: voja
author_rank: Contributor
timestamp: January 13, 2015, 08:58:20 pm
content: I have to design the PIC controller with prerecorded multi-messages (for some stand-alone Bingo blower, with no PC support) and in my previous project, I used Nuvoton's ISD4004. In the datasheet they say that their analog NV memory cells with zero compression (patented, blah, blah...) guarantee the good sound quality. But it was catastrophic, approximately at the telephony quality level! So I redesigned it for ISD15100, which has the following characteristics:ADPCM: 2, 3, 4 or 5 bits per sample?-Law: 6, 7 or 8 bits per sampleDifferential ?-Law: 6, 7 or 8 bits per samplePCM: 8, 10 or 12 bits per sample. Each sampled value is stored as a code, offering no compression but preserving maximum resolutionI made the new PCB design, but before I order my PCBs, is there any hint? Some better idea? Is it worth trying with dsPIC µC some other time?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 13, 2015, 09:16:17 pm
content: SPI flash and CD player DACSPI flash is ridiculously cheap these days (like 4Mbits for $0.10), especially from SpansionYou can stream direct from the flash to the DAC, using the SPI clock (data doesn't pass through the micro).
Embedded Computer Design - Page 1
Forum section: electronics / projects

author: IntegratedValve
author_rank: Regular Contributor
timestamp: January 13, 2014, 08:10:43 pm
content: Maybe this is too much to ask for in one question, but I only need advice on how to start building my own embedded computer system. I want to use uP and RAM to run Linux. the system has to produce fast graphics so I need a graphics processor. Is there any guide I can refer to on creating an embedded computer? Thanks.

author: nctnico
author_rank: Super Contributor
timestamp: January 13, 2014, 09:49:52 pm
content: Get a reference design for a Freescale or TI Omap device and go from there.
Embedded computer using Allwinner H3 - Power management - Page 1
Forum section: electronics / projects

author: dingari
author_rank: Contributor
timestamp: July 26, 2016, 11:51:05 am
content: Hi, my team is staring work on an embedded computer using the Allwinner H3 SOC and we have a few questions to get out of the way regarding the power management.I've looked at the FriendlyArm NanoPi (both NEO and M1) and OrangePi Plus schematics (all using Allwinner H3), and they seem to be using seperate regulator ICs for the different voltage rails. While the CHIP computer (Allwinner R8) is using a single AXP209 PMU IC (including a battery charger).My product will run from a battery, so I'm leaning more toward the single PMU IC route. I've foundAXP209,AXP221,AXP223andAXP809, which all seem to be fitting. I've not looked too much into the differences, but the AXP221 or 223 seem appropriate at first glance. The AXP809 is also much more expensive than the others.Is this a cost / size / availability tradeoff? Or is there another reason the H3 boards all utilize seperate ICs?Also, what WiFi + Bluetooth chip would you recommend?NanoPi M1 schematic:http://wiki.friendlyarm.com/wiki/images/d/d8/NanoPi-M1-1603-Schematic.pdfNanoPi NEO schematic:http://wiki.friendlyarm.com/wiki/images/a/aa/NanoPi-NEO-1606-Schematic.pdfOrangePi Plus schematic:http://pan.baidu.com/s/1bnppzv5CHIP schematic:https://github.com/NextThingCo/CHIP-Hardware/blob/master/CHIP%5Bv1_0%5D/CHIP_v1_0_SCHEMATIC_20151203.pdf
Embedded graphic LCD library - Page 1
Forum section: electronics / projects

author: Harvs
author_rank: Super Contributor
timestamp: November 22, 2012, 11:40:11 am
content: Anyone using a generic graphic LCD library that's available at low cost (or even better open source...) preferably able to do both colour displays and monochrome. I don't care about the hardware interfacing routine, that’s easy. It's just the routines for drawing everything in RAM that I'm finding time consuming.A colleague suggested having a look at C/PEG before he left for the week, but it looks like that is going to be quite expensive for a one off project.I've started writing my own, but to be honest, writing graphics routines don't really enthral me. I'd much rather be spending my limited time getting the hardware and control system sorted...I’ll probably be running it on a PIC32 or move over to ARM.

author: enz
author_rank: Regular Contributor
timestamp: November 22, 2012, 12:33:13 pm
content: I have no idea regarding a solution for the PIC. But since you are already considering a move to ARM, i recommend to especially consider a NXP device and take a look at the lpcware site.http://www.lpcware.com/content/project/emwin-graphics-libraryIf you are happy with an object library and don't need the source code of the graphics library then NXP provides you with an unlimited license (private and/or commercial use) of Seggers emwinhttp://www.segger.com/emwin.html.This is a very powerful graphics library.I plan to use it in one of my next projects.Regards,Martin

author: Harvs
author_rank: Super Contributor
timestamp: November 22, 2012, 01:07:18 pm
content: Looks great, another reason to move to arm!

author: baljemmett
author_rank: Unknown
timestamp: November 22, 2012, 01:51:55 pm
content: I've not looked at it or used it (just spotted it whilst looking for something else), but Microchip appear to offer a graphics library for their 16- and 32-bit chips; it's part of their freeLibraries for Applicationsbundle.

author: ptricks
author_rank: Frequent Contributor
timestamp: November 22, 2012, 02:49:54 pm
content: The glcd programs by Mikroelektronika, work on multiple targets and doesn't cost too much.http://www.mikroe.com/visualglcd/Downside is you have to use one of their compilers. Combined with the compiler though it has been the fastest way for me to get GLCD and TFT working . They include features like touch screen controls, animations, loading data from sd card for display, fonts, bitmaps. The one program works with any of their compiler platforms, so if you want to do pic and use it later on arm you just have to export it for arm.
Embedded GUI Software Tools - Page 1
Forum section: electronics / projects

author: jmag999
author_rank: Contributor
timestamp: August 05, 2014, 11:51:10 am
content: I am looking for recommendations on Embedded GUI software tools. Has anyone used something they like? I will be running on a Kinetis K70 processor with an 800x480 display. Would like to have anti-aliased font support. In the past, I have used EasyGUI, which worked well. But I am starting this design from scratch and was wondering if there is anything better out there. I am looking for something that creates a set of C files.This one looks impressive, but so far have not been able to get a pricehttp://www.altia.com/

author: Kjelt
author_rank: Super Contributor
timestamp: August 05, 2014, 12:35:19 pm
content: No experience with it but I know this one:http://www.segger.com/emwin.htmlQuite pricey (from 1,5k€ upto 10k€) but for some targets in combination with their development tools the pre compiled libs are free of charge (NxpExpresso, STM32), not for the K70 though AFAIK.

author: TerraHertz
author_rank: Super Contributor
timestamp: August 06, 2014, 05:19:40 am
content: I know this isn't what you want, since you already have a hardware platform. But just 5 minutes ago I'd read this:Nvidia Jetson TK1 Reviewedhttp://www.drdobbs.com/embedded-systems/nvidia-jetson-tk1-reviewed/240168804?&elq=4d238d3375694f5a846370ba90a9a57d&elqCampaignId=6983Which is relevant due to enabling a really powerful GUI on a small single board.

author: dannyf
author_rank: Super Contributor
timestamp: August 06, 2014, 11:00:12 am
content: emwin and ucgui.

author: VEGETA
author_rank: Super Contributor
timestamp: May 12, 2016, 05:21:08 am
content: I intend to make a GUI that shows video feedback of a camera and various other stuff, while controlled by FreeRTOS. Is there any solution which is free or cheap?
Embedded Linux Project with a SAM9G45 ARM Microprocessor - Page 1
Forum section: electronics / projects

author: Write_to_Smokegenerator
author_rank: Regular Contributor
timestamp: March 13, 2012, 11:08:45 pm
content: Hello everyone!I started a project with a friend of mine.What is it?Basically it's a motherboard for this device:www.ic-board.de/data/datasheet/305000044B_ICnova%20SAM9G45%20SODIMM.pdf(don't worry about the German description features are still in English )We have an 10" Display which will serve as a Screen for the OS.Also there will be an XMEGA-A1 connected via SPI to the ARM processor.All kind of functions of the Arm and the Xmega will be available through connectors (like I2C, SPI the ADC and 1 DAC interface of the Xmega, the Ethernet port of the ARM, the USB interface of the ARM and so on..)We want to use 2 SD Cards for memory purpose (1 is only for the ARM OS)What we did so far:build separate modules 1 ARM PCB and 1 XMEGA PCB (both 2 layer 100x160mm)both PCBs were manufactured at home.the ARM Module is assembled so far and currently under test (looks good so far but the Linux gives my friend trouble)the Xmega PCB is finishedWhat we'll do next:Assemble the Xmega PCB.testing our 2 PCB'sWhat we want to in the distant future:Build both parts on one 4 Layer PCB (also 100x160mm but if bigger ones don't cost so much more we might go up with the size)We're not quite sure if it's possible to do it on a 100x160 with all our specs but it's still to early to tell because we're far away from being finished.Here are some pics of the PCB's more information will come soon^^http://www.flickr.com/photos/77940640@N04/6980482467/#topview - XMEGA-PCBhttp://www.flickr.com/photos/77940640@N04/6834338766/#closer look-XMEGA PCBhttp://www.flickr.com/photos/77940640@N04/6834339168/#bottom view of the Xmega PCBhttp://www.flickr.com/photos/77940640@N04/6980467489/#ARM PCB general viewhttp://www.flickr.com/photos/77940640@N04/6980468079/#ARM PCB closer lookThe Xmega PCB has the nickname (so ugly can be a piece of modern art, because the first Layout was so ugly)Cheers.
Embedded USB host for USB - GPIB communication - Page 1
Forum section: electronics / projects

author: franciscoPT
author_rank: Contributor
timestamp: January 08, 2025, 11:55:48 am
content: Hi, i have designed a pcb to communicate with a equipment via a USB - GPIB cable, from prologix, in my PCB i used a FTDI FT232RL to convert usb to uart connected to a stm32, i have tested the prologix with a computer and got it to work, and the same thing for my PCB, but i cant get the PCB to communicate with the prologix, i made some search and i believe that the problem is not having a host in the usb line, does this make sense? if is that the problem how can i solve it?, someone have some feedback on the vincullum IC of ftdi? can i use it for my purpose?

author: abeyer
author_rank: Frequent Contributor
timestamp: January 08, 2025, 08:08:27 pm
content: Quote from: franciscoPT on January 08, 2025, 11:55:48 amCorrect, you absolutely can't connect two usb devices directly without a host.Quote from: franciscoPT on January 08, 2025, 11:55:48 amI'm not familiar with them, but a quick glance at the datasheet seems like it could be part of a solution. Looks like you'd still need to write a firmware for it to handle the direct interface of the prologix, if you wanted to support that, and maybe for the ft245r as well... not clear if any of the prebuilt ones would work.
Embedded Video Design - Page 1
Forum section: electronics / projects

author: karken
author_rank: Newbie
timestamp: July 17, 2017, 03:17:51 am
content: I am looking for some advice on how to handle video data in an embedded system. My situation is this, I want to take the raw data from a CMOS camera and store the information to an SD card. Naturally, the raw data from the camera is uncompressed and would severely limit how much information I could store so I would assume it is common to encode the data into a more compressed form. From the research I have done it looks like h.254 is a very common codec on full blown computers, but I have no idea what is typically used in embedded systems. Additionally, how is the encoding usually handled? Do take the information and plug it straight into a micro controller and via firmware encode the stream? Do you send the data to some sort of encoding chip (if so can you show me an example) that then goes to a micro controller? Do you send the raw data to an FPGA and have that do the encoding? I have found the Di Vinci series of chips by TI and they seem like the closes thing I could find to solve this problem.http://www.ti.com/product/tms320dm365Also how do DSPs factor into this situation?Any wisdom from some one who has done this before, or knows how it is typically done, would be greatly appreciated.

author: Jeroen3
author_rank: Super Contributor
timestamp: July 17, 2017, 06:08:30 am
content: These media processors are often custom silicons of the brand that uses them. But there are a few catalog ones, TI and NXP have a few.https://en.wikipedia.org/wiki/Image_processor#Processor_brand_names

author: karken
author_rank: Newbie
timestamp: July 17, 2017, 11:57:53 pm
content: Thanks for the reply Jeron3, yah it looks like the Di Vinci chips form TI may be my only realistic option. Truly those chips look pretty good so I don't think it is a bad option. Additionally, I wonder if it is possible to implement the encoding in an FPGA. I checked github to see if there where any verilog/vhdl H.264 projects but I didnt see any. Lastly, I think I could always just run embedded linux and see how well it preforms with the encoding. If anyone is interested in this let me know, I will be checking out the options.

author: aandrew
author_rank: Frequent Contributor
timestamp: July 18, 2017, 02:47:23 pm
content: While there is nothing wrong with Davinci processors themselves, the support surrounding them is horrendous.RidgeRun was hired by TI to create GStreamer drivers and libraries to use the Davinci hardware. Thing is, RidgeRun also needs to make money. The stuff you can get for free is *ancient* and full of known issues. RidgeRun's answer is "pay us, we have code that runs with current GStreamer and fixes the issues."I don't blame RidgeRun, I blame TI. I'd stay far, far away from Davinci. I've been involved in several projects using these devices and it's always an exercise in frustration. TI's support on Davinci, at least for the hobby and low volume (<10k) crowd is pathetic.
Embedding electronics in concrete/cement - Page 1
Forum section: electronics / projects

author: QSmits
author_rank: Newbie
timestamp: March 13, 2013, 01:37:45 pm
content: A few months ago I had the idea of embedding a grid of temperature sensors (like the DS18B20) in the floor of our new (still under construction) house. I don't know if it will actually be useful, but it'd be a fun project and these sensors aren't too expensive (if they still work after being embedded in the floor, that is..).Would there be anything against embedding electronic components in concrete or cement?

author: SeanB
author_rank: Super Contributor
timestamp: March 13, 2013, 04:15:10 pm
content: No problem, just encapsulate them in an electronics grade silicone, and then place inside a PVC conduit that will be buried in the concrete. As they are 1 wire devices just use a CAT5 cable and place each sensor in the one pair, so that you have a long string of them after encapsulation to put in the pipe. Seal the far end and bring the tail end up through an elbow to a junction box in the wall, so that you can connect to it. When doing the concrete lay them down and tie to the reinforcing, and place the junction box in position, with 3m of cable free wrapped up in a bundle and cable tied to the junction box, the box being wrapped in heavy plastic for protection and to keep the builders from breaking it. After cure mark the conduit position and use the construction measurements to mark the sensor positions on the concrete with either some acrylic paint or stain.

author: ftransform
author_rank: Frequent Contributor
timestamp: March 13, 2013, 04:54:16 pm
content: Go read about the American built soviet embassy (or vice versa?) which included all sorts of interesting concrete spy electronics, including batteries which ran on the concrete reaction lol

author: Ratib
author_rank: Newbie
timestamp: March 13, 2013, 06:06:03 pm
content: That was the American Embassy in Moscow, sometimes known as the "roach motel" due to the amount of bugs built into it. i do not remember "concrete batteries" but bowtie antennas that were designed to power bugs when microwaves were directed at the building.
EMC - CM DM separator - Page 1
Forum section: electronics / projects

author: mattko
author_rank: Contributor
timestamp: October 03, 2018, 08:40:22 am
content: Hello!Does anybody know where it is possible to buy a CM DM separator for conducted EMC measurements? I found proposed circuits like this onehttps://www.edn.com/Home/PrintView?contentItemId=4169136.I allready contacted the company aemc.fr, however I couldn't find anything on their website.If it is not possible to buy it I Will make it, but I imagine it is a bit tricky with frequency responses of transformers and other components...Any tips would be welcomeThanks!

author: 2N3055
author_rank: Super Contributor
timestamp: October 03, 2018, 10:51:05 am
content: Checkhttps://www.tekbox.com/product/tblm1-lisn-mate/
EMC Problems with Arduino Nano - Page 1
Forum section: electronics / projects

author: luky315
author_rank: Regular Contributor
timestamp: August 17, 2023, 09:42:37 pm
content: I have a product that failed EMC precompliance testing.It uses an Arduino Nano clone (chinese version with the CH340 and with as bad schematic and layout as the "original") and not much else appart from a bunch of LEDs (with PWM dimming, 5mA each), switches and connectors. We saw a noticeable emission around 120MHz but strangely no significant harmonics, just this line. Any ideas what this can be? It is for sure from the Arduino because it disappears when the microcontroller is in reset.

author: Niklas
author_rank: Frequent Contributor
timestamp: August 19, 2023, 08:34:10 am
content: What type of measurement, radiated or conducted?What do you have connected to your test object? Is the Arduino board connected as a CPU module to some kind of kind or motherboard, possibly with several cables attached?What is used to power the test object?

author: Shonky
author_rank: Frequent Contributor
timestamp: August 19, 2023, 09:57:44 am
content: Conducted is typically only up to 30MHz so would be radiated.First thought was USB related as 480/120 is neat and there's usually some multiple of 20MHz around but CH340 is only Full Speed USB so should only have a 12MHz clock.What other clocks are there including on your board?Got some near field probes?

author: luky315
author_rank: Regular Contributor
timestamp: August 19, 2023, 11:04:12 am
content: The USB is not connected, the Arduino Nano is used as a cheap "CPU module" and there is not much else on the main board except of a few 5mA leds which are driven by a PWM (directly from the AVR), no long wires or anything. This could make some noise, but then I would expect to see a lot of harmonics and not a single line at 120MHz. It looks like some kind of oscillation, but there are no DC/DC regulators (just the LDO on the Arduino) and no Opamps or something similar that could oscillate.I didn't expect any problems with this product and was very surprised.

author: moffy
author_rank: Super Contributor
timestamp: August 19, 2023, 11:31:23 am
content: My guess would be the CH340 chip and its 12MHz crystal, even though the USB is not connected the CH340 could still be signaling the D+ and D- wires as well as its own 12MHz square wave clock. Can you disable the chip and its oscillator as a test since it is not in use?

author: luky315
author_rank: Regular Contributor
timestamp: August 19, 2023, 12:04:47 pm
content: I think that I have to desolder it since the CH340 has no RESET Pin but it is definitely worth a try. Interestingly it is the CH340C variant with the internal clock, so there is no 12MHz oscillator.
EMC Standards - Page 1
Forum section: electronics / projects

author: PixieDust
author_rank: Frequent Contributor
timestamp: April 26, 2020, 08:00:58 am
content: I'm currently reading about EMC standards, ACMA/FCC/CE compliance. I'm just looking at the description of "AS/NZS 61000.6.3-2012" haven't bought it yet. It says:"Adopts IEC 61000-6-3, Ed.2.1 to specify emission requirements in the frequency range 0 Hz to 400 GHz for electrical and electronic apparatus intended for use in residential, commercial and light-industrial environments."Seems pointless even buying it for me given that the frequency range goes to 400Ghz! I haven't looked, but I'm sure a spectrum analyser with that kind of bandwidth would cost as much as a house. Can anyone shed some light on this? How can a standard intended for the broadest category of consumer goods require testing to such high frequencies? It would make most useless trinkets economically nonviable to develop, yet there's so much stuff on the market. Confused!

author: OwO
author_rank: Super Contributor
timestamp: April 26, 2020, 08:09:35 am
content: The frequency you are required to test up to is some multiple of the highest clock or RF frequency used in your design. The standard has to go up to 400GHz to define requirements for <100GHz ISM band applications.

author: PixieDust
author_rank: Frequent Contributor
timestamp: April 26, 2020, 08:34:11 am
content: And why are there multiple applicable standards next to some categories? Do you need to comply with all, or does compliance with one suffice?

author: PixieDust
author_rank: Frequent Contributor
timestamp: April 28, 2020, 10:58:41 am
content: Quote from: PixieDust on April 26, 2020, 08:34:11 amAh, found thishttps://www.compeng.com.au/wp-content/uploads/2014/10/ACMA_C-Tick_booklet.pdf:QuoteThis raises a question. I haven't checked the requirements in Europe or USA yet, but at least in Australia, you basically can sell a product if it complies with these other standards i.e. if it just has an FCC sticker if it's coming from America etc? Why are there multiple jurisdiction certifications available by EMC Compliance testing facilities if at least in Australia, it seems to accept multiple certificates?Also, the following:QuoteThis is quite interesting, immunity isn't a requirement! At least for what I'm planning to make.

author: Neilm
author_rank: Super Contributor
timestamp: April 28, 2020, 07:08:48 pm
content: Selling into Europe you will need to look at the the standard that is applicable to your product. For instance test and measurement equipment requires meeting IEC 61326. That specifies the frequency range ithe unit has to meet for emissions and what immunity testing is required - it variy depending on the product and where it is used.For EMC you may have to meet either the EMC directive or the Radio Equipment Directive (if you have a transmitter in the unit). It would also have to meet the Low Voltage Directive for safety as the CE mark covers both. Depending on your product you may have to meet other directives - those are the ones I am immediately familar with.
EMC testing - Page 1
Forum section: electronics / projects

author: keef46
author_rank: Contributor
timestamp: February 16, 2021, 10:36:32 am
content: Can anyone recommend any EMC test houses and also any freelancers in the UK that can assist with pre-compliance testing and resolving EMC issues that crop up?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 16, 2021, 10:38:58 am
content: If you're in the south-east :https://www.rnelectronics.com

author: jc101
author_rank: Frequent Contributor
timestamp: February 17, 2021, 05:24:13 pm
content: I've used these people a few times now, very helpful and offered suggestions as to how to resolve some errant emissions. I found them quite reasonable costs wise too.There are near Cambridge.https://www.dbtechnology.co.uk

author: penfold
author_rank: Frequent Contributor
timestamp: February 17, 2021, 06:09:47 pm
content: Test houses... in the North, York EMC (now part of Eurofins) and Element (Skem or Hull branch have been good in my experience).As for freelancers, if you get stuck finding someone, drop me a PM, I may be able to make a recommendation but I forget which of them has what kit available and it would depend a little on specific product area.
EMC testing - Page 1
Forum section: electronics / projects

author: lgbeno
author_rank: Frequent Contributor
timestamp: March 20, 2014, 01:01:14 pm
content: Totally random question but does anyone have a picture of a ferrite sample case from a EMC chamber. I was telling a co-worker about them but need a picture to give a full explanation...

author: MartinX
author_rank: Regular Contributor
timestamp: March 20, 2014, 06:29:43 pm
content: Something like this TDK datasheet may do the trick:http://www.mouser.com/ds/2/400/e9s-23129.pdf
EMERSON 7001605-j000  mod to 13.8V ????? - Page 1
Forum section: electronics / projects

author: Fizfi
author_rank: Newbie
timestamp: December 22, 2022, 06:36:02 am
content: Does anyone have knowledge about the voltage adjustment for this power supply?I couldn't find anything specific to this model online and the control PCB looks quite different to the many videos I have seen regarding adding or removing resistors for the other various models. There are only 2 potentiometers and the one to the right only gives minimal adjustment up to about 12.32v.Any advice or pointing to other resources much appreciated! This PSU seems to be made by FRU and original p/n is 7001605-j002IBM P/N 94Y8070

author: bingo600
author_rank: Super Contributor
timestamp: December 24, 2022, 04:22:51 pm
content: Just a hint ...FRU is an IBM term for "Field Replaceable Unit" , not the Manuf.

author: Fizfi
author_rank: Newbie
timestamp: December 24, 2022, 06:48:43 pm
content: I do not understand what do you mean?

author: ded0145
author_rank: Newbie
timestamp: December 28, 2024, 04:37:34 pm
content: Good morning, I came across this post for the same reason as you, I'm wondering if you've found a solution as I can't find anything online.Thank youRoberto
EMG data acquisition - Page 1
Forum section: electronics / projects

author: Moturki
author_rank: Newbie
timestamp: August 31, 2018, 02:35:13 am
content: HelloI'm working on project called"design & implementation of EMG data acquisition",I search on these systems but I really confused about what the gain required and the filter type I have to use.at first stage i use instrumentation amplifier to amplify the signal, so how much the gain of this stage should be?the second stage which is filtering out unwanted frequency components, which type of filter should i use to get a very clean EMG signal and how much should the order of filter be?thanks.......
EMG front-end design-review wanted - Page 1
Forum section: electronics / projects

author: kxenos
author_rank: Frequent Contributor
timestamp: October 18, 2016, 11:00:37 pm
content: Sorry, no one's interested, so I think I should delete the post

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: October 20, 2016, 08:01:17 am
content: Oh wew, much more complex circuit then what I had (at least it must work). Also attached schematic is outdated, OPAMP was changed to MCP6004, instrumentation amplifier was changed to INA826, and full-wave rectifier was changed to one that can work with a single supply. Need to get back to it once higher priority tasks come down.For the skin contacts I tried using a couple of uSIM headers but not sure how well that would have worked since build circuit had a few issues (should have breadboarded it first). I have also got some proper ones (the ones that have gel on the sticky pad), so have that to fall back on. Is that what you meant by connectors?

author: kxenos
author_rank: Frequent Contributor
timestamp: October 20, 2016, 08:40:39 pm
content: Nevermind

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: October 22, 2016, 01:08:38 pm
content: Ah gotcha, the cables I got use a 3.5mm audio jack, any reason not to go with this?

author: kxenos
author_rank: Frequent Contributor
timestamp: November 19, 2016, 05:10:29 pm
content: Nevermind
EMI considerations for LED PWM dimming - Page 1
Forum section: electronics / projects

author: exp1
author_rank: Contributor
timestamp: January 05, 2014, 06:38:55 am
content: Hello, I am thinking about installing some of those cheap 5m 12v LED strips in my apartment and want to be able to dim them. The issue is that i just realized that I would be rapidly switching currents in the order of 2 amps in and out of pretty long strips of copper. I have a feeling that such a device would be a pretty powerful interference radiator, so I got thinking of ways I could make the whole thing as quiet as possible while retaining dimming capabilities.Filter high frequency components (ie: increase rise time): That should put an upper limit to radiated frequencies, but also would reduce the efficiency of the dimmer considerably, plus would impose a hard limit on the switching frequency.Use the lowest reasonable switching frequency: Lowest limit would be what causes annoying flicker at any light level, I've read about using 200Hz at least. I dunno if it would be better to use a mains frequency harmonic and phase lock with it to bury the noise there.Spread spectrum on the PWM frequency(long shot?)If it has to come to that, perhaps consider constant current drive, though I have my doubts on feeding so many series-parallel series circuits with a constant current supply.I'd like to hear your opinions on the matter, is there something I hadn't considered yet?
EMI considerations on LC filter SMPS - Page 1
Forum section: electronics / projects

author: MacIntoshCZ
author_rank: Regular Contributor
timestamp: January 03, 2024, 07:38:22 pm
content: I have two stage LC filter, by two stage i means this:https://ridleyengineering.com/images/phocadownload/1%20second%20stage%20filter%20design.pdfCoil in first stage is placed on noisy node (100Khz 250V peak), first idea i got was to place inductors at "grounds nodes" (see picture to get idea what i mean by that, and ignore thats seconds stage inductor) but by doing so, feedback loop will mess up.So this is probably not the way i guess. Or is that possible? I never saw that to be honest =D. Even most of application notes has coils next to cap+ nodes....So probably the only way is to use shielded inductor. Dont know if i can rely on Ycap connected to the enclosure, since EMI is my invisible enemy number one =D.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 03, 2024, 09:33:58 pm
content: If ground is declared after the inductor, that's fine. This likely precludes sync rect and common-ground (non-isolated buck/boost) applications. But other than that, the loop doesn't know anything different.I suppose I can assume isolated, since you mention Y cap. Notice there is a common mode path through the series capacitors, so the Y cap can still be placed at the output ground side without much difference.Back in the day, ground-side chokes were a common trick to alleviate isolation ratings in transmitters -- otherwise it would have to stand off the full, whatever, 3000V the transmitter is powered by -- way back in the tube amplifier days that is, where a 5kW transmitter might use 3kV 2A or so, into a forced-air or even water-cooled ceramic triode or tetrode.Tim

author: MacIntoshCZ
author_rank: Regular Contributor
timestamp: January 04, 2024, 04:18:20 pm
content: You are right, thanks for noticing!Yes, its isolated!

author: MacIntoshCZ
author_rank: Regular Contributor
timestamp: January 04, 2024, 05:15:15 pm
content: Do you think its necessary to have inductor isolated? Since it will be in conductive enclosure connected wit Y cap to primary and secondary ground, it should limit EMI to go outside, but inside enclosure it could affect near electronics.I am trying not to place anything sensitive nearby. In worst case its peaking at 250V 100Khz. Its rise time/ fall time what matter the most
EMI feedthrough filter product and manufacturer recommendations - Page 1
Forum section: electronics / projects

author: matthuszagh
author_rank: Frequent Contributor
timestamp: September 03, 2023, 05:53:31 pm
content: I'm looking for EMI feedthrough filters to pass power into a Hammond enclosure. What products and manufacturers do other people use for this? I was planning to use a Pi filter.From a look on Mouser, Tusonix / CTS sell quite a few of these and the performance (at least judging by the datasheets) look good. Some of the prices are reasonable, others are quite high. One filter that looks good is4202-004LF. However, it's quite large. Apart from space considerations, I haven't been able to find a terminal lug lockwasher for a #12 thread.Sort of related: I haven't been able to find chassis-mount pins for ground connections (as an alternative to the terminal lug lockwasher). I know these exist because I've seen them in finished assemblies. Can anyone point me in the right direction here? What are these called. What's an example product number?
EMI filters on Mains ( do you use them on DIY projects )  - Page 1
Forum section: electronics / projects

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: August 29, 2011, 03:45:36 am
content: EMI filter on Mains,metallic box mostly found in respectable devices, in the AC input of them.By voting you are showing how much do you care about them.Personally, I remove them from dead devices so to add them on my own projects.

author: PeterG
author_rank: Frequent Contributor
timestamp: August 29, 2011, 05:11:47 am
content: My projects are mostly low voltage and don't run directly off mains power.Regards

author: JuKu
author_rank: Frequent Contributor
timestamp: August 29, 2011, 05:45:27 am
content: A few years ago I got a few integrated AC inlet/switch/EMI filter components. Whenever my project has an AC input, I use those.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: August 29, 2011, 07:59:43 pm
content: I try to power things with wall warts, but if building something line powered I almost always use a Corcom or similar filter. The side benefit is they usually accept standard line/mains cords.

author: Gall
author_rank: Frequent Contributor
timestamp: August 29, 2011, 08:57:03 pm
content: I use Meanwell power modules, they have built-in EMI filters and fuses.

author: Psi
author_rank: Super Contributor
timestamp: August 29, 2011, 09:04:04 pm
content: Totally depends what your project is doing.No point putting an EMI filter on an electric blanket.

author: corlickmark
author_rank: Newbie
timestamp: January 08, 2012, 09:32:34 am
content: Well,EMI filteris just like any any other filter that try to reduce the frequency interference by filtering the frequency. I like to collect them and make a note about their rating so that i can use them in some of my own small projects like frequency jammer, FM transmitter etc.
EMI foam on top of ICs - Page 1
Forum section: electronics / projects

author: subliti
author_rank: Contributor
timestamp: July 06, 2019, 01:24:20 pm
content: HiI saw this teardown video from Dave (https://youtu.be/sKcH4JxnxbQ?t=992) and some of the chips had some kind of emi foam on top of it. I never saw this before and i find it interesting. Does this only work for low freq and does something similar exist for high freq ? And what is high or low freq in this context ?I was wondering....could one reduce the overall noise floor of a rf radio chip that is in the same enclosure with a bunch of other chips lika a mcu etc if i put this foam on top of the mcu etc, could this improve something ? Even if the rf section is already shielded by a metal case, could this improve something ?

author: Kleinstein
author_rank: Super Contributor
timestamp: July 06, 2019, 01:43:00 pm
content: A closed metal can is a RF resonator. For the really high frequency stuff (> 1 GHz) sometimes addition absorbers are added to dampen the resonances. The higher the frequency the more important it gets.Having this in a low frequency meter is odd. I am a bit with Daves guess - maybe a desperate late addition to meet EMI requirements.

author: coppercone2
author_rank: Super Contributor
timestamp: July 06, 2019, 02:37:54 pm
content: those digital chips can make high frequency emissions (MCU).If the converter has a pass transistor built into it then maybe? It could maybe have a high impedance some where that is being modulated by digital signals to effect a power rail (acting as a RF amplifier mainlining noise into the power rail at low impedance).
EMI for beginners: DAB Radio - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 10, 2020, 11:29:03 am
content: I built myself a VFD clock... it has...12V inputVoltage regulator (TPS5410) 12V -> 5VVoltage regulator (TPS61175)12V -> 70VFilament Supply (LM4871) 5V -> 5V ACMultiplexed IV-18 VFD tubeMy multiplexing is based around a 27kHz interrupt27kHz across 9 digits... = 3000 ticks/digit gives 100 'frames' per digit per second for effectsIt all works (although I do notice a certain amount of instability of brightness in the digits which I am investigating) but today I came across a big problem...I have a DAB radio which just about locks to BBC Radio 4 which I leave burbling along in the background whilst I work but today I discovered that if I turn my VFD clock on... DAB drops out entirely... nothing!The clock is not yet in a case... but I intended to use perspex so had not planned any shielding.What should I do next? Stop listening to DAB?Thanks

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 10, 2020, 12:52:44 pm
content: Yikes... that sounds hideous!Did you use ground planes?Tim

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 10, 2020, 01:03:22 pm
content: If your reception is already marginal than there's not much needed to stop it from working. First thing I'd say is trying to get a better reception by either moving the receiver to a better spot or hooking up an external antenna if that is possible. Of course you can also try to find the course of the interference but that will only work until you bring in another device and kill the reception again.Do you have a spectrum analyzer? If so you could examine the clock with a (home-made) near field probe and see where the problem is. If you stop the multiplexer is the problem gone? How do you create the 5V AC, is there an oscillator involved that is a bit too enthusiastic? Switch it off and see what happens. Ferrite beeds can actually help to suppress unwanted radiation, try them on the 12V entry and make sure you have no wires longer than needed. Lastly, a picture would be nice!

author: NivagSwerdna
author_rank: Super Contributor
timestamp: January 10, 2020, 01:29:02 pm
content: Quote from: PA0PBZ on January 10, 2020, 01:03:22 pmYeap DAB was barely working anyway; I have to wiggle the antenna to get a signal without distortion.Unfortunately I don't have a spectrum analyser. The design does have ground planes.I'm interested in what would be throwing the DAB off... isn't it up in the 200MHz range... miles away from the operating frequency of the clock.

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 10, 2020, 01:35:33 pm
content: Yes it is around 200MHz but you only need one square wave in your clock to get there, we are talking uVolts. I'd enable part by part of the clock (or the power supply) and see where the problem is. You mentioned flickering, that could also point to something oscillating that shouldn't oscillate. Time to get one of those SDR sticks for $15 I'd say.