hybridfree/eevblog-posts huggingface dataset:
WLP-72 is it possible? - Page 1
Forum section: electronics / projects

author: soubitos
author_rank: Frequent Contributor
timestamp: February 25, 2018, 07:46:58 pm
content: Has anybody experience working with WLP72 chips?What kind of vias, track width etc you use? Is it absolutely needed to go for a 4 layer pcb?And can the average chinese pcb manufacturer handle them?Is it possible for the average hobbyist to have such a prototype made (i dont expect to solder this, will go for PCBA service of course but desing the pcb and have it made???)

author: Rerouter
author_rank: Super Contributor
timestamp: February 26, 2018, 10:27:35 am
content: The footprint itself, relying on 0.25mm pad diameters just clears the manufacturers clearances of 0.2mm, however that does not help you for breakout of inner traces,if you have a single pad to break out, your out of luck, you will need tiny plugged vias, if you have 2x2 groupings of pads to break out, you can just make it work. with a soldermask coated 0.3mm / 0.6mm annular via which the cheap manufacturers allow.If you have the small vias / via in pad, the number of breakout layers comes down to whether pin functions are unique or grouped, most small packages will group things to reduce the number of layers required, if its for instance the MAX77818 (only thing i could find using that package), there own datasheet shows how to break it out on 2 layers.

author: soubitos
author_rank: Frequent Contributor
timestamp: February 26, 2018, 09:13:35 pm
content: Quote from: Rerouter on February 26, 2018, 10:27:35 amThat is the culprit... but am going to abandon the idea of using it, not so much because of how demanding it is on the pcb side but because of cost/functionality which does not cover my task 100%.....Thank you anyway for taking the time to post, my endeavor in the world of electronics probably will bring more like this one my way sooner or later so dealing with it is not something i will be able to avoid after all ... but for now Adios Amigo!
WNTD  antenna teardown  - Page 1
Forum section: electronics / projects

author: daniel444
author_rank: Regular Contributor
timestamp: August 04, 2019, 01:50:17 am
content: got a few of these wntd outdoor units from my local dumpim planning on mounting a 30w to 60w cree led cob to the raised square part of the castingi have machined it perfectly flat , as far as machining goes this material is great to work onits 900grams of aluminumill probably also mount some 18650s and a boost driver in there also for a portable lamphas anyone else come across lots of these ?im not sure what to do with the electronics i took out of it as its above my level, ill probably take it back to the dump

author: daniel444
author_rank: Regular Contributor
timestamp: August 04, 2019, 03:34:34 am
content: this is how the unit looked before the teardownhow common are these units? , i wouldn't mind getting some more

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 04, 2019, 03:17:16 pm
content: Post a higher resolution picture of the board (including part numbers of the chips) and we'll determine if it is worth hacking for personal use. I would have to guess at least one of the wireless cards is Wifi, but also apparently mini PCI (as opposed to mini PCIe or M.2) and probably too old to be worth much.
Word Clock [Generator] (a watch not a frequency generator ;-) ) - Page 1
Forum section: electronics / projects

author: pknoe3lh
author_rank: Regular Contributor
timestamp: March 06, 2017, 09:42:52 am
content: Hey Everyone!Want to share my new finished ProjectYoutube:https://youtu.be/fn1k5g4bUQ0(English Version)https://youtu.be/0pOK-t7EvA4(German Version)Photos:https://goo.gl/photos/oPc46iBzidNVpt4Q7The Word Clock Generator:https://github.com/pknoe3lh/WordClockGenerator(Source)https://github.com/pknoe3lh/WordClockGenerator/releases(Binary)Hope someone find this useful!greetingsPatrick

author: pknoe3lh
author_rank: Regular Contributor
timestamp: March 06, 2017, 12:02:34 pm
content: Hello Willfed,Thanks for the feedback!The next half a year I will not have a lot of time to make new Videos .... but I'm positive!!!Yes Its is distracting. I tried explaining all important stuff verbal.I don't have the resources to make Videos like you linked.So when i do a project i focus on that and after i cut and narrate the Video.The Idea is also to get a feeling about the "true" effort and not the one selected seen in other videos.Will see when i have more time in the Future i will try to make a Video like you posted.I also planing in making Tutorial Videos. There i will also not use high speed content.Will see how it develops.greetingsPatrick

author: pknoe3lh
author_rank: Regular Contributor
timestamp: March 07, 2017, 09:08:33 pm
content: I tried ... Actually its not that much effort :-)https://youtu.be/tNPpLDylUQ0Tell me how you like that.greetingsPatrick
Word clock project (LED matrix) - Page 1
Forum section: electronics / projects

author: 8086
author_rank: Super Contributor
timestamp: December 22, 2013, 06:17:34 pm
content: .

author: liquibyte
author_rank: Frequent Contributor
timestamp: December 22, 2013, 06:31:17 pm
content: Not sure how you intend on programming things but I recently did a number to names conversion usingthis code. I'm not even sure this would be useful to you, I just gave that page a cursory look. My clock was a lua plugin for conky if anyone's interested in how I did things it'shere.

author: Relaxed
author_rank: Contributor
timestamp: December 23, 2013, 08:49:48 pm
content: Nice project! I just finished a word clock myself.I control the words as a whole, so I just need to have 24 outputs. I use an Atmega 328 with 595 shift registers and high side drivers.For the front panel I had to buy the original one from clocktwo, because getting it made locally would be much more expensive and I didn't want to gamble with quality.If you have any questions, just ask.

author: Relaxed
author_rank: Contributor
timestamp: December 29, 2013, 10:23:18 am
content: I'm just using a DS1307 RTC. But I would probably use a more precise RTC for the next project.

author: IanB
author_rank: Super Contributor
timestamp: December 29, 2013, 11:10:40 am
content: What do you think makes this clock uniquely different? Is it just the words, or maybe the large square design, the backlit letters, the artistic statement, or something else?Because clearly you could tell the time in words on any typical dot matrix display. I imagine the appeal is more to do with the large, picture size design that hangs on the wall like a piece of art?
Ignore me!  - Page 1
Forum section: electronics / projects

author: Vertigo_01
author_rank: Newbie
timestamp: September 16, 2016, 05:55:31 am
content: Nevermind. Ignore me! I missed a pre-existing thread!I'm picking up a few new pieces of test equipment, and their addition to my workbench means that I'm now at a point where I'm going to need to redesign my workbench, including the shelving to hold the test equipment...Rather than asking for specific ideas, I thought I'd ask if people could post their favourite workbench designs for myself, and others, to draw inspiration from.So... Who has photos and/or design schematics for either their own workbench, or even just things you've seen on the internet and especially liked?Really cool I-wish-I-had-that-on-my-bench features?Pitfalls or things that you've seen implemented poorly?

author: daqq
author_rank: Super Contributor
timestamp: September 16, 2016, 06:16:11 am
content: This is already being discussed here:https://www.eevblog.com/forum/chat/whats-your-work-benchlab-look-like-post-some-pictures-of-your-lab/

author: Vertigo_01
author_rank: Newbie
timestamp: September 16, 2016, 06:36:43 am
content: Doh!I don't know how on earth I missed that one. Sorry! I swear I tried to look about, but somehow managed to skip past that thread!
Working on Adj Current/Voltage SMPS Lab PSU. Questions... - Page 1
Forum section: electronics / projects

author: FenderBender
author_rank: Super Contributor
timestamp: September 17, 2011, 02:49:29 pm
content: Hi everyone,I'm kind of a newbie so if I sound like a moron, that's probably why.I'd like to design my own switchmode bench supply that can be configured to have an adjustable current limit and adjustable output voltage.I like National's Simple Switcher chips, as I've used an LM2576-5.0V once before and it worked very well.However, I need a simple way to do this and I don't want to use an L200c for that would mean huge transformer, huge heatsinks, and a big pricetag. At which point a commercial PSU is probably the best option. I figure that I can build my own for quite cheap if I use a switching design and have something that I can trust.So I was going to try to use a LM2576-Adj which National has a nice 1-30V adjustable schematic for in the datasheet. But I'm too stupid to figure out how to do adjustable current limit. I know you'd probably need some op-amps or something, but really don't have much of an idea of how to do it correctly.Then I saw the LM2673 which is called "3A Step-Down Voltage Regulator with Adjustable Current Limit", but it SEEMS that in the datasheet, that you can't have a very wide output voltage range due to something with inductors and capacitors and resonance they have with eachother. However, I don't know that for sure. LM2673 also switches at 260KHz which means I have more places to screw up my layout.So I have a few questions. Does anyone have a decent solution to adding adjustable current limit to the LM2576? If not, how about getting a full range of voltage adjustment on the LM2673? If not, do you have any other ideas for this? Other chips/designs etc?Thank you.

author: Gall
author_rank: Frequent Contributor
timestamp: September 18, 2011, 09:38:38 am
content: Generally, adjustable current limit is done independently of the chip. Voltage too.You just measure both voltage and current using opamp-based circuits, compare them to references and provide a feedback to the regulator. The regulator may be SMPS or linear, doesn't matter.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 18, 2011, 01:05:09 pm
content: Take a look at power converters intended for charging batteries, since those need to control both voltage and current.
Working with CSI - Page 1
Forum section: electronics / projects

author: machinehum
author_rank: Contributor
timestamp: February 17, 2022, 06:29:12 pm
content: I'm working with an Allwinner A33, which is a 1.2Ghz quad core MPU. I want to connect this to two cameras, however, I have two problems.There is only one CSI bus.The CSI format is "CCIR601" which appears to be synonymous to: Rec. 601, BT. 601 and ITU.RHere are some details pulled from the datasheet.My question is a four-parter.Is there a way to interface two camera into the same bus?Is the defacto standard to find a sensor that has this output, or do some conversion? In hardware or otherwise.Does anyone have some documents or resources for learning more about this? I'm not sure if it's obvious but I'm pretty new to working with cameras at the sensor level.Is there a huge matrix of camera sensors anywhere?

author: ra.hulk
author_rank: Newbie
timestamp: September 22, 2023, 09:54:39 am
content: You can use 2:1 multiplexer, I used this TS3DV642A0RUAR. You will only be able to get data of one camera at a time. I dont know your exact requirements and my reply is probably too late. Might be helpful to future someone.
Working with domestic & Overseas manufacturers/suppliers - Page 1
Forum section: electronics / projects

author: bearman
author_rank: Regular Contributor
timestamp: March 21, 2011, 01:38:02 am
content: I have several questions regarding getting product to market. Mainly relating to partnering with overseas manufacturers. I live in the U.S. If any fellow Yanks that can provide feedback I appreciate hearing your experiences.1) Dave you always talk about buying parts from providers (ie; Digikey etc.) for products you are building for yourself and your work.A thought came to mind about this. If you are a manufacturer of a product that you are going to sell retail don't you shop for wholesale pricing for materials that you would be selling? Digikey and such are retailers are they not?2) Once you have a total cost (parts, packageing documentation and such) and want to sell your product at a retail outlet how do you determine your retail price to customer and distributor price for vedor selling your product.? Someone once told me to charge 5 times your cost.3) When ordering product from overseas, mainly China, do you talk live with anyone or just through emails to discuss your product needs? I assume companies will have English speaking agents available. Are they staffed with folks that can communicate efficiently in Engrish?4) When ordering buying products from overseas does the U.S. require any taxes or duty to be paid? Hopefully someone from the U.S. can answer this.5) Do overseas providers charge any taxes/duty when shipping to the U.S.?6) Any other gotchas to be aware of when buying from overseas providers? Besides buying stuff that may compromise national security. LOLJohn

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 21, 2011, 01:51:27 am
content: Quote from: bearman on March 21, 2011, 01:38:02 amDepends on quantity. For passives they are usually already so cheap it's not worth the hassle shopping around.More expensive stuff can often be bought cheaper from franchised distributors but they will often only deal in whole reels or other high min order qtys, and may not carry stock so you may have weeks or months of leadtime.QuoteNot that simple - partly due to what the market will bear, and also your development costs, which are rarely related to parts cost.QuoteAbove a certain value there are usually import duties.QuoteNo. Duty is always on import, not export. But obviously there will be shipping costs.

author: bearman
author_rank: Regular Contributor
timestamp: March 21, 2011, 02:15:15 am
content: Thanks for the quick reply.
World's Smallest Power Supply 3-25v, 2Amp - Page 1
Forum section: electronics / projects

author: Kedar264
author_rank: Regular Contributor
timestamp: December 23, 2015, 06:46:59 am
content: Watch The Videohttps://youtu.be/0I_GVAxdO9M# Features1. 3-25v Adjustable Voltage Output2. Built in 720mAh Battery Backup3. 2 Amp Max Current4. Built in Live LED Voltmeter5. Built in Voltmeter For Quick Measurement6. In Built 3.7v Battery Charger

author: Molenaar
author_rank: Regular Contributor
timestamp: December 23, 2015, 11:37:22 am
content: How stable is it under load and how does it react to transients?

author: SeanB
author_rank: Super Contributor
timestamp: December 23, 2015, 12:01:35 pm
content: Kedar, hope you cleaned up Umma's kitchen afterwards.Does anybody want to send him a new soldering iron to replace the firestick he has, just to improve his soldering skills. I still have one or two of those wood burners around, usable in a pinch, or to solder up radiators.

author: retrolefty
author_rank: Super Contributor
timestamp: December 23, 2015, 12:27:18 pm
content: Great project for a beginner DIY.Not only does one have a reasonable chance at success but they also end up with something useful when done. Telling a beginner that they shouldn't start without first reading and understanding the datasheet used for the buck SM regulator chip.

author: zapta
author_rank: Super Contributor
timestamp: December 25, 2015, 07:26:02 pm
content: Very nice project. A small case will be useful.Quote from: SeanB on December 23, 2015, 12:01:35 pmOr a Hakko clone handpiece to power it by this portable power supply (with some temperature control loop added).

author: pmbrunelle
author_rank: Regular Contributor
timestamp: December 26, 2015, 05:26:53 am
content: Disclaimer: I don't do small stuff; nothing below 0805.But I don't see what the fuss is over soldering stations. For my personal hobby stuff, I use a mains-powered Weller WP-35 (apparently has some bi-metallic strip temp control) as my main electronics soldering iron for PCB work, and a Weller 140/100 W soldering gun for the heavier jobs (soldering ~16 AWG wire and larger).At work, I sometimes use a Hakko FX-951 soldering station, and I don't find it works any better... it just takes up more desk space.OP needs to improve his basic soldering technique before worrying about getting the fancy equipment.The highest priority purchase should be a vise, so that OP can hold parts securely without grinding off his fingers with a Dremel.
worlds lowest noise circuits ? (cryogenic) - Page 1
Forum section: electronics / projects

author: CopperCone
author_rank: Super Contributor
timestamp: July 04, 2017, 10:47:06 pm
content: What kind of noise figures can be expected from cryogenic amplifiers.?This thread is meant to be a discussion/general overview of expected real-world behavior of cryogenic circuits.what happens to 1/f noise?Discussions about all frequencies is welcome. This is meant to be a more of a fun threadI would also like for people to post stories about cryogenic circuits and practical lab stuff, etc. A broad discussion of low noise low temperature design and implementation.

author: CopperCone
author_rank: Super Contributor
timestamp: July 05, 2017, 10:48:07 pm
content: https://www.eevblog.com/forum/metrology/quietest-voltage-for-testing/relatedhttps://www.eevblog.com/forum/metrology/quietest-voltage-for-testing/

author: MK
author_rank: Regular Contributor
timestamp: July 06, 2017, 07:38:25 am
content: http://www.picovolt.com/win/elec/articles/Lepaisant_preamp-xfmrs_RSI.pdf65pV rt Hz good enough to count?
World’s sexiest Tesla Coil (Vertical). - Page 1
Forum section: electronics / projects

author: @rt
author_rank: Super Contributor
timestamp: May 31, 2016, 01:20:32 pm
content: Any sexier (Vertical) Tesla coil out there pls let me knowBearing in mind it’s an SLA powered baby!!

author: DutchGert
author_rank: Frequent Contributor
timestamp: May 31, 2016, 02:28:32 pm
content: I want!

author: Arjan Emm
author_rank: Regular Contributor
timestamp: May 31, 2016, 03:42:56 pm
content: I think mine is sexierNicely made though!Wooden black base like yours and alot of acrylic like yours, including the secundairy.Shame it needed a recoil after this run.

author: @rt
author_rank: Super Contributor
timestamp: May 31, 2016, 05:12:32 pm
content: Well it clearly wins in performance!For mine the secondary coil wire part is about 35cm, but this assembly ends up closer to 60cm.With regard to aesthetics, those new tube torus shapes have something going for them visually.However, yours will remain the same, while mine will become many times more sexy

author: tantulatum
author_rank: Newbie
timestamp: June 02, 2016, 02:56:50 am
content: I've always like this one. Fiber optic LCD remote control.

author: @rt
author_rank: Super Contributor
timestamp: June 02, 2016, 06:55:58 am
content: For the World’s sexiest vertical Tesla coil, that could just be assumed haha :The nicer keypad from RS is in the cardboard box at the back.

author: Psi
author_rank: Super Contributor
timestamp: June 02, 2016, 07:33:06 am
content: Quote from: tantulatum on June 02, 2016, 02:56:50 amFiber optic SS Tesla coil control is very common.It's not a good idea to have a conductive piece of wire between you and the coil electronics

author: @rt
author_rank: Super Contributor
timestamp: June 16, 2016, 02:20:42 pm
content: Ok, One more part to go for this assembly. I have it, but not fitted yet.It’s a matching acrylic base shape that goes under the ground plane,so that it looks like a silver band around the perimeter of the base.For the top disc, it’s kind of a shame it covers the more detailed clear stuff, but it should still be there.Laser cutting is getting expensive!! :O

author: alsetalokin4017
author_rank: Super Contributor
timestamp: June 16, 2016, 03:29:04 pm
content: Can I play too?(Powered by 2 x 12v SLA batteries)

author: Gyro
author_rank: Super Contributor
timestamp: June 16, 2016, 04:15:53 pm
content: Quote from: Arjan Emm on May 31, 2016, 03:42:56 pmThat soundtrack was worthy of 'Forbidden Planet', particularly the way as the pitch increased.
World's Simplest Soft Latching Power Switch Circuit doesn't work - Page 1
Forum section: electronics / projects

author: aveei
author_rank: Newbie
timestamp: September 20, 2018, 10:03:08 am
content: Hello to allSo I've built the circuit as in the video but the only thing which happened was that one of the supply wires got burned without me doing anything.Is this circuit really supposed to be like this since the base/gate of the p channel transistor will always be grounded and I've checked that a P channel transistor gets on with a positive voltage to the baseAfter a couple more tries the base of the p channel transistor is always grounded

author: alexig
author_rank: Contributor
timestamp: September 29, 2018, 10:55:28 am
content: Hi there,You shouldn't be using a PNP transistor, it's a P mosfet that was shown in the video.The gate needs to be isolated otherwise current will flow through the E-B when the switch is pressed.Here's a handy circuit simulator program you can try the circuit in -https://www.falstad.com/circuit/
Worth doing GSM based project? - Page 1
Forum section: electronics / projects

author: engineerguy
author_rank: Contributor
timestamp: March 27, 2018, 01:26:03 pm
content: So early last year I started a personal project to create a GSM based dev board, I got so far as to create the schematic and PCB in KiCad. The whole project was based around the Quectel M95 module:http://satronel.com/product/Quectel/M95I purchased one in anticipation of using it...however I didn't realise that 2G/GSM was being phased out in Australia, with the last carrier closing off the network in September that year. I didn't get around to completing the project on time, to be able to send an SMS and whatnot, but I still have the part, and I still have the design files...so I'm wondering whether there's anything else I can do?

author: mjs
author_rank: Regular Contributor
timestamp: March 27, 2018, 04:23:36 pm
content: Check if their LTE Cat-M1 modules (like BG96) have the same footprint. Seems that Cat-M1 is being rolled out down there. Network registration time, energy budget and especially power supply design is much nicer when you get rid of 2G!

author: engineerguy
author_rank: Contributor
timestamp: March 28, 2018, 02:10:09 pm
content: Thanks for your input. Seems like my options are very limited then? :/

author: engineerguy
author_rank: Contributor
timestamp: March 29, 2018, 11:02:07 am
content: Nobody else have any ideas?
Wot no SCLK using FT2232H - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 22, 2022, 02:03:07 pm
content: This is driving me nuts...A while ago I built a breakout board using FT2232HL-REEL and now I am trying to use it to read the ID from an SPI deviceNothing was working with the real device so I unhooked it and added my cheapo Logic Analyser to it and I see..i.e. SCK seems to be missing... there is a CS and some data going out on MOSI but nothing on SCLKAccording to the schematic SLK should come out of pin 16 but I am seeing a flat linepin 17 and pin 19 (not wired on the schematic but shown on the logic analyser trace) are looking lively.I check continuity and it looks like I am really observing pin 16This has me stumped! Why isn't my FT2232H sending a clock out on pin 16PSI am driving it via pyfdi on Win10.

author: Ian.M
author_rank: Super Contributor
timestamp: May 22, 2022, 03:41:20 pm
content: Pin 16 of the FT2232H is TXD1 in UART mode, (UART channel A) so configure it as a pair of COM ports and send data to it on whichever one is channel A. If neither port wiggles that pin, you've got a blown pin! If it wiggles, there's probably a problem with your Python configuration code using pyftdi.Sorry I've only got a CJMCU FT232H board here so I cant offer tested code or test your code.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 22, 2022, 04:12:36 pm
content: I like your thinking... I was in denial about having a faulty output...Reset the drivers and configured as an output..COM3... nothing on pin 16COM4... nice wobbles on pin 38Looks like that chip is heading towards the bin! Shame they are super expensive and relatively hard to find now... at least I have a few spares.Will report back when I have replaced it.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 22, 2022, 08:10:50 pm
content: Wow... well that pretty much wiped out a days work...When I went to replace the FT2232H I was about to reflow and then on inspection under the microscope I saw that the gap between pins 15 and 16 wasn't quite as distinct as I would expect... I couldn't see a short it just looked a bit 'wrong'... reflowed the area around 16 and...Thanks Ian.M, I needed that prod.
Would like some help understanding power supply circuit - Page 1
Forum section: electronics / projects

author: Bratster
author_rank: Frequent Contributor
timestamp: October 03, 2017, 01:29:31 am
content: Hello,I would like some help understanding what this circuit is doing.This is from a fluke BC 190 power supply / battery charger for the 19x scopemeter series.It seems to be mostly unregulated so I'm not sure why they put so much circuitry in this.Two out of the three Active Components I'm not sure what they are. I just used a transistor schematic symbol, but I don't actually know what they are.ThanksSent from my Nexus 6 using Tapatalk

author: rmacintosh
author_rank: Regular Contributor
timestamp: October 03, 2017, 01:45:19 am
content: The 431 makes it a 4.3v zenerThe other marking DGs makes it a generic PNP transistorLooking up small SMD markings parts is really easy with this cross referencehttp://www.dl7avf.info/charts/smdcode/cc.html#TOC

author: amspire
author_rank: Super Contributor
timestamp: October 03, 2017, 01:55:46 am
content: The 431 is a TL431 regulator IC.http://www.ti.com/lit/ds/symlink/tl431.pdfIt regulates so that the voltage between the REF to Anode is 2.5V.

author: expinkolator
author_rank: Contributor
timestamp: October 03, 2017, 03:47:39 am
content: The circuit probably looks like the attached. The value you have for R1 looks wrong.Q3 emitter is held at about half supply which means about 2mA flows through R4. Some of that flows though Q3 and R5 generating a +ve voltage on Q1 gate to turn it on. Q1 turning on pulls OUT- low until there is enough voltage between OUT+ and OUT- for the TL431 to start drawing current from R4 and tend to turn Q1 off. There should be 2.5v across R2 and 17.8 - 2.5 across R1, R1 and R2 values should have that ratio.Your voltages indicate there is no regulation, Q1 has probably failed short circuit.

author: Bratster
author_rank: Frequent Contributor
timestamp: October 05, 2017, 05:49:15 am
content: Thanks everyone for the input!I should be able to take another look at this this weekend.I will look and see if that mosfet is shorted as well as check the other two of these that I have and see if they're output voltages line up with this one or not.Sent from my Nexus 6 using Tapatalk
Would like to have some feedback on my Trezor One Layout (pretty Newbie) - Page 1
Forum section: electronics / projects

author: M_a-r_k-u_s
author_rank: Newbie
timestamp: December 26, 2021, 11:55:24 am
content: Hi together,I'm quite new to PCB-Layout and would be thankful if you could give me some feedback on this PCB-design. I pretty much used the exact schematic of the Trezor One, which can be found on Github  and then only did the PCB-layout myself to practice PCB layouting. SMD parts I changed to 1206 for easier hand soldering.I'm particular unsure in my layout about the tracks underneath the STM32 on the bottom, if this could cause signal integrity issues because the bottom is otherwise a solid GND-plane. You can also comment on other things if you want to. I'm also not completely sure if the oscillator placement and routing is ok or could be done better.Thanks,Markus:https://github.com/trezor/trezor-hardware/tree/master/electronics/trezor_oneEdit: The stackup is 2-layer board with 1,6mm

author: jwet
author_rank: Frequent Contributor
timestamp: December 26, 2021, 09:37:40 pm
content: I think its looks very good especially for someone new at this. The tracks under the STM32 are no problem. Your use of a ground plane is a good choice, the circuit will be pretty quiet but this isn't really necessary- lots of microcontroller boards like this were made double sided without any planes. You have to take some care with bypassing and routing grounds well with fat traces. I love the test points- nice job. With boards being so cheap and quick these days, I'd check it over one more time and send it out for fab. It will work even if there is a little rework. You'll probably have a final cleanup pass anyway for little things or parts availability, etc.I noticed a few small things that are mostly just comments-1. Those two USB traces going through R3 and R4 are routed awfully close together- as long as your board vendor can do the line widths and and the spaces, its no problem but I don't think there is a good technical reason for this. These are USB D- and D+ and while they have to be matched, etc, they don't require this level of effort.2. All the traces on the board are pretty small, they look like 6 or 8 mil. If you're hand soldering, you might want to make all the traces 10 or 12 mils where they'll fit. Tiny traces are easy to overheat, lift pads, etc. Use the most conservative design rules that will work- its easier for everyone and improves yields.3. I don't see any mounting holes, this can be easy to overlook when you get buried in the routing.

author: M_a-r_k-u_s
author_rank: Newbie
timestamp: December 29, 2021, 12:30:19 pm
content: Hi jwet,thanks for your commenting I appreciate it.Unfortunately I can't get the board assembled b/c you don't get any STM32 uCs these days - but that's another issue.
Would the HDS200 really benefit from thermal pads? - Page 1
Forum section: electronics / projects

author: GelatinCapacitor
author_rank: Contributor
timestamp: June 16, 2024, 09:04:45 am
content: I just acquired the HDS272S.On this video for a more recent model of the device, they show an installed 'improvement': thermal pads on the ICs that generate most of the heat.I am seriously thinking about performing the same. But would it really help or even be necessary?Of course, I can gather that these thermal pads' heat capacity is not special at all, but at least they're good at conducting the heat, and the increased surface area would help transfer the heat to air or possibly nearby parts on the pcb.Does that make sense? What if this does not extend the device's life at all? The ICs may not even get too hot at all.A different video showed the device from the outside, on thermal camera approaching 33C°, while ON, after many minutes, laying flat on a 23°C table. But who knows what temperatures the ICs themselves were at.Look at my silly drawing:EDIT:done

author: tooki
author_rank: Super Contributor
timestamp: June 16, 2024, 09:07:16 am
content: The point of a thermal pad (or thermal paste, etc) is to be a better conductor of heat than air, which is quite poor. You get the heat out of the confined area and move it to a larger place where you can dissipate it.

author: GelatinCapacitor
author_rank: Contributor
timestamp: June 16, 2024, 09:18:59 am
content: And I assume that the thermal pad layer should always be as thin as possible.But I'm assuming the point here is to make the thicker thermal pads serve as better heat sinks than the surrounding air is; but they may not actually make that much of a difference.

author: 2N3055
author_rank: Super Contributor
timestamp: June 16, 2024, 09:27:21 am
content: Thermal pad is a spreader, an interface. On the other side of the pad you need a heatsink. A metal plate, metal case or something. An actual heat sink..

author: tooki
author_rank: Super Contributor
timestamp: June 16, 2024, 10:54:54 am
content: Quote from: GelatinCapacitor on June 16, 2024, 09:18:59 amAs thin as possible, but as thick as necessary: it’s still a better conductor of heat than air is!Why do you think it wouldn’t make a difference?

author: GelatinCapacitor
author_rank: Contributor
timestamp: June 16, 2024, 02:52:59 pm
content: Being specifid to this situation. Just trying to prove both sides.It'll help because the little mass avaiable will absorb the heat better.It won't because there is still nowhere directly to spread to.

author: SeanB
author_rank: Super Contributor
timestamp: June 16, 2024, 04:27:58 pm
content: Thick pads do at least spread the heat out to a larger area, even if it is plastic it will have a larger surface area to transfer heat through to ambient.
Would this intelligence which do PWM? - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: June 07, 2016, 06:28:07 pm
content: Would the attached smart MOSFET be any good for a power PWM control? I have just noticed that it has no ground to terminal so I can only assume that every time it is turned on or is it off by grounding the input it boots up its internal circuitry and perhaps stays alive for some time after turning off. But if it has a bootup time then presumably the lag to switch on will be horrendous and maybe it's not something that wants to be turned on and off continuously?

author: CM800
author_rank: Frequent Contributor
timestamp: June 07, 2016, 06:34:30 pm
content: Honestly I wouldn't even think about it. No:

author: Simon
author_rank: Unknown
timestamp: June 07, 2016, 06:35:12 pm
content: I was looking for those figures. I was going to use it at low-frequency but as you say I think it's totally the wrong device perhaps

author: Siwastaja
author_rank: Super Contributor
timestamp: June 08, 2016, 06:04:36 am
content: Why not, if you are going to PWM at a really low frequency, for example, a heater.But generally, I'd think the frequency should be 1/100 of the transition time max, i.e., around 20Hz.This could maybe very barely PWM a light bulb at 50Hz without too much visible flicker.

author: Simon
author_rank: Unknown
timestamp: June 08, 2016, 06:25:59 am
content: I'm going to use one of their half bridge drivers, it's more suited to the job and will be more flexible, even has a variable slew rate.

author: batteksystem
author_rank: Regular Contributor
timestamp: June 08, 2016, 09:32:17 am
content: Quote from: Simon on June 08, 2016, 06:25:59 amThese are good as ON/OFF switch, but not so good as motor driver for PWM. I think Infineon has some updated Smart MOSFET which can do PWM up to 100KHz.

author: Simon
author_rank: Unknown
timestamp: June 08, 2016, 04:37:59 pm
content: I'm using a BTN8982TA as i can switch either way and it will do PWM.
Would this opamp circuit work / is it a bad idea - Page 1
Forum section: electronics / projects

author: justinjja
author_rank: Regular Contributor
timestamp: January 18, 2016, 01:54:50 am
content: Circuit should input a single ended or differential signal,and then output it as balanced signal.Would the output #1 actually be the same as the inverse of the output #2?Is there a spec that determines how close they would be? (2x input offset voltage maybe?)Thanks.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: January 18, 2016, 02:11:51 am
content: Hi,It is a bad idea. There is no feedback around the lower op-amp.Keep the top amplifier. Configure the bottom op- amp as follows:Ground + inputResistor from top amplifier output to - input on bottom amplifier. And equal value resistor from - input to output of bottom amplifier. This make the bottom amplifier have a gain of -1.Regards,Jay_Diddy_B

author: ThomasDK
author_rank: Regular Contributor
timestamp: January 18, 2016, 04:20:12 am
content: Quote from: justinjja on January 18, 2016, 01:54:50 amNot really, this is one of the things that works in spice, and never will in reality.The input offset is one reason, but imagine what a 1 mv offset difference will do with a 1000x gain difference. You pretty much have to factor in everything with a "min/max/typ" value in the datasheet.

author: dom0
author_rank: Super Contributor
timestamp: January 18, 2016, 12:28:55 pm
content: Re. differential input amplifiers and fully differential amplifiersMake _sure_ that you really need at and that you really need the CMRR. Good CMRR requires very tight matching of components, both absolute and in tempco to get repeatable, stable performance.Think about your input and output requirements, what kind of CMRR you need etc. This will save you a lot of trouble.If you have no hands-on experience in this area it is probably simpler, cheaper, faster and better to use an integrated amplifier. They are available from TI, AD, THAT Corp and cost a couple bucks each, but these monolithic amplifiers generally have performance that is hard to achieve in a discrete op amp circuit.Edit: Oh, and if you want to build this as a box... DI boxes are commonly available and usually can do diff/SE <-> diff conversion, among other things.
Would this work as a variable high pass filter? - Page 1
Forum section: electronics / projects

author: theleakydiode
author_rank: Regular Contributor
timestamp: March 17, 2021, 06:21:01 am
content: Would this arrangement work as a variable high pass filter at the input of an audio amp? I've tried LTspice but I can't work out how to work it. Also what variable resistor value should I use for it have give good adjustability?I assume it would do something but what would the rolloff look like when plotted?I'm a bit of a noob,Thanks.

author: bob91343
author_rank: Super Contributor
timestamp: March 17, 2021, 06:27:45 am
content: The way it's set up you have two high pass filters in parallel. Turning the pot varies the contribution of one filter. With the pot at max the filter uses one capacitor. With the pot at zero, the frequency is dropped one octave. In between I think you will get a combination of the two. Of course this isn't a sharp filter so the results won't be startling.Imagine the cutoff characteristic of the filter in each extreme pot setting, and the characteristic would be a curve in between the two.Just a guess.

author: Berni
author_rank: Super Contributor
timestamp: March 17, 2021, 06:47:36 am
content: Yep as bob said this is two filters in parallel.You will probably get bit of a step in your cutoff response where you can run that step up and down with the potentiometer.The better way is to adjust that resistor to ground. This is what will actually shift the cutoff frequency back and forth. The values for that can be calculated using the online RC high pass filter calculators.Also if you expect the cutoff to be very sharp, this will not do it. Sharp cutoff filters need a different design or multiple stages.

author: thequantizer
author_rank: Newbie
timestamp: June 24, 2021, 04:34:56 am
content: Try simulating it and you can see how it will behave. We have a post that includes a video on how to simulate a RC High Pass Filter in KiCad. Just modify the circuit to look like your design and see how it works!High Pass Filter Calculator

author: magic
author_rank: Super Contributor
timestamp: June 24, 2021, 05:09:53 am
content: Quote from: theleakydiode on March 17, 2021, 06:21:01 amSet V1 value toAC 1.Replace VR1 with a resistor and set its value to{pot}.Presssand add.step param pot 0 1000 100or similar.Set simulation command to AC and choose your frequency range.Enjoy

author: mikerj
author_rank: Super Contributor
timestamp: June 24, 2021, 08:58:03 am
content: A 10k variable resistor will give a -3dB range of approximately 110-250Hz, assuming negligible source impedance and very high load impedance. I have attached a simple LTSpice model that you can experiment with.
Wrist watch enclosure, off the shelf and waterproof - Page 1
Forum section: electronics / projects

author: Poe
author_rank: Frequent Contributor
timestamp: February 28, 2020, 07:25:52 pm
content: Just found this while looking for a boring square box:https://www.serpac.com/bw-series.aspxI tried to make a custom watch around 2002 reusing my old Casio TV remote wrist watch enclosure.Prices for HDI have dropped significantly since then. Maybe it's time to revisit.

author: IDEngineer
author_rank: Super Contributor
timestamp: February 29, 2020, 12:31:46 am
content: Seeing those makes me want to design something with them, just because.
Wrist watch project... Micronucleus bootloader question. - Page 1
Forum section: electronics / projects

author: Chris3D
author_rank: Newbie
timestamp: January 23, 2019, 12:09:24 am
content: Hi all,Just thought I'd share this project and see if anyone could answer a bit of a technical question.I'm making a wrist watch for my son (he's 9 years old). It displays the time in two rings of LEDs, 12 each for the hours and minutes. It rounds the minutes to the nearest 5 minutes because who really needs to know the time any more accurately than that... not my son at least!Here's a video of it so far:I'm pretty much down to just finishing up the code and then designing and milling a housing from aluminum. So, on to the question...I wanted to keep the component count as low as possible so I could make the board as small as possible, so only one button, no external crystal on the Tiny841, no level shifting between components running at different voltages. Everything is powered from the lipo cell, soldered directly to the board. One everything is powered down/put in sleep mode between button presses, the board only draws .02 mAh, so it'll run for months between charges when not being used. The 5v from the USB only goes to the lipo charger IC.In a bit of an oversight, I discovered that with the Tiny841 powered full time from the battery, it doesn't reset when I unplug/plug in a USB cable... obvious in hindsight. So, that means the Micronucleus bootloader doesn't do the initial wait to accept programming. Not a huge deal, I've just been grounding the reset pin side of a pullup with some tweezers when I need to program it, and once the code is finalized, there won't be a need to reprogram it often, if at all. But... if I could reset it in code, that would be nice.I've tried to use the watchdog timer to initiate a reset, but it appears it's either not working at all, or a watchdog reset doesn't reset to a point early enough in the boot process for the Micronucleus boot loader to do it's programming wait. I read about reset vectors, but that's where it starts going over my head.So does anyone know if a watchdog reset is the equivalent of cutting/returning power, and if not, are there any other ways to force a full reset in software? Again, not a huge deal if not. I'd love to hear any feedback on the project as well.Thanks in advance.

author: Chris3D
author_rank: Newbie
timestamp: January 24, 2019, 05:04:00 pm
content: In case anyone else comes across the bootloader "issue" (not really an issue), the solution is in the configuration file when compiling the bootloader.There's a define: #define ENTRYMODE which can be set to always, watchdog, external reset or jumper. Setting it to always or watchdog and recompiling will cause the bootloader to enter programming mode on watchdog resets. I was kindly pointed to the solution by Gerben on Stack Exchange.
Wristwatch (also sun tracker ) MPU interface waterproof buttons - Page 1
Forum section: electronics / projects

author: eneuro
author_rank: Super Contributor
timestamp: May 07, 2015, 09:46:28 am
content: Hello,Another small PCB designed as simply interface for my custom wristwatch and sun tracker controler where I need MPU interface with waterproof buttons.Idea behind this is put four (~SMD 1206) NPN phototransistors in the corners of 1inch2 (2.5cm x 2.5cm PCB) with 13 LEDs in the midle (in the case of sun tracker another phototransistors there to catch sun light shadows and fine tune thermal solar CSP system to align with sun rays if clear sky available to help RTC keep perfect parabolic mirrors positioning).Anyway, my concern are those four buttons, while need this interface to be waterproof and in the case of wristwatch additionally pressure proof.While I might want also reflash MPU (or better implement boot loader capable reprogram itself) using four light sources eg. 1inch2 part of LCD screen or even cell phone displays to send flash program memory via those MPU interface buttons to bootloader, my first thought was using photodiodes or NPN phototransistors.It has some advantage, while in sun tracker control device I might need measure available sun light (it will work usually at daylight), so I will need them, so I thought it could be nice forget about capacitive buttons.I've found quite cheapy NPN phototransistors, so I will be able make prototype and see how this concept works in practice, but maybe someone see any pitfalls in this approach?Maybe something else, but probably it could allow me make MPU bootloader capable to reflash this thing using cell phone directly from my WWW page with video on demand based on customer settings and preferences without messing with reprograming those MPUs (Atmel AVRs) using classic programators, etc....

author: eneuro
author_rank: Super Contributor
timestamp: November 15, 2015, 07:47:18 pm
content: After a while, instead of using phototransistors in the corners, back to the idea of using 12 LED + one in the middle to display watch clock and sense light by using two cascaded74HC595to drive leds small curents and select given LED to sense lightI will use vias in pads to save PCB space while want this watch PCBs stacked one of top of another keep small and maybe I will use wireless charging using... PV solar cellsIdea is this watch should work forever powered by daylight (sun) and survive huge water pressure, so no bloody mechanic buttons, etc .It will be available in black with green display/sense leds
Writing a Service Manual from Scratch? - Page 1
Forum section: electronics / projects

author: Chris56000
author_rank: Frequent Contributor
timestamp: May 31, 2019, 08:25:22 pm
content: Hi!Has any Member ever attempted to take a piece of Test or other Equipment for which the schematics are either simply not made available, like all T & M oems claim is now industry standard practice, or known to exsist but refused, like Chauvin Arnoux, or where the OEM had them but has destroyed/disposed of remaining stocks, like Keysight does with old C.L.I.P.'s, and write/draw a complete Service Manual covering Specifications, Operation, Theory of Operation, Adjustment/Calibration, Fault Finding, Dismantling, Parts Lists, Circuit Diagrams & Layouts?I myself have but ended being distracted by domestic demands, car woes or bother at my employment that has diverted my mind away from the task, and by the time whatever else I had to do was completed, my train–of–thought on manual–writing had gone!I would be interested to see a home–authored Service Manual if any Member can point me in the direction of one!Chris Williams