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His Divine Shadow posted:I added some 1uf capacitors and I got a slight hiss, that's about where I started out, it was like real bad last night so it's an improvement but a static hiss again. I tried different cables and one stereo to mono jack gave a hiss free sound. Do you have a ground loop?
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Feb 14, 2024 06:16
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I'm not sure, how would I determine that?
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Feb 14, 2024 07:09
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Rocko Bonaparte posted:Does somebody have a recommended method for homebrew PCB's or should I just get them fab'd? Toner transfer works with solid reliability here. I use iron (3) chloride etchant just because it's always available in the lab where i work. Benefit compared to getting boards made is that you can design your board in the morning, and have the circuit board the same afternoon. When i have the design, the whole process from printing to having a finished board takes 30-45 minutes for a single sided board. Double sided is a whole other can of worms, DIY'ing via's is no fun. Quality of the board houses is almost always better than what you do yourself. But i want things quickly so i still do my own boards. LimaBiker fucked around with this message at 08:08 on Feb 14, 2024 |
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Feb 14, 2024 08:06
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Rocko Bonaparte posted:Does somebody have a recommended method for homebrew PCB's or should I just get them fab'd? For single- or double-sided that fit in the work envelope, the various 3018 CNC routers work pretty well. Etching works well, too.
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Feb 14, 2024 13:38
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LimaBiker posted:Toner transfer works with solid reliability here. I use iron (3) chloride etchant just because it's always available in the lab where i work. Toner Transfer is definitely the easiest to get going if you already have a laser printer and works well enough, yeah. I've moved on to UV but it's definitely more fiddly, needs more stuff to do it and has a lot more variables to adjust. But yeah the only benefit is you can get your board in like two hours instead of a week, and if you can wait a week then getting it fab'd is better 100% of the time.
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Feb 14, 2024 14:13
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Rocko Bonaparte posted:Does somebody have a recommended method for homebrew PCB's or should I just get them fab'd? Yeah there's no way this is worth the effort anymore. Especially considering what you can get for like 25 cents per board and $20 shipping (queue up a couple boards to spread that out if you like, but even paying full shipping every single time is worth it). Even 4 layer boards have gotten so cheap I almost don't even bother with 2 layer anymore, unless the board is very large and would make 4 layer prohibitively expensive. If nothing else, the proper solder mask makes SMD soldering so much easier, the frustration alone is worth it. Add in stuff like having a silkscreen, lining up vias and holes on a 2 layer board, etc.... no loving way.
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Feb 14, 2024 16:48
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I'm pretty amazed by that. I never did my own PCB and my memories of it go back to classmates doing senior projects in college something like 20 years ago. So I figured I was going to have a miniature meth lab going on to prototype some stuff. I'm just making a board to reroute pins for the Jumperless breadboard and various microcontrollers and microprocessor projects I have here like an ESP32 board I want to use, some older and newer Raspberry Pis, and some other things. So I was assuming I'd need a 2-layer just for worming stuff around. Now I get screw around in KiCAD for the first time.
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Feb 14, 2024 17:20
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His Divine Shadow posted:I'm not sure, how would I determine that? If the phone is being powered by a charger and the charger is grounded separately from the stereo, that's a classic ground loop. You can also have AC ground loops where maybe there's not a physical connection back to ground but there's some stray capacitance between your phone or your cable and ground. My experience with ground loops has been that they pick up power line hum more than static though. The best example I can think of is my car, where the line-in connector is between the seats and I keep my phone charger in the cigarette lighter connector in the dash. Each of these has its own local ground but the phone winds up being part of a huge ground loop and picking up a lot of alternator whine and ignition noise. The only way to get good sound is to unplug the phone from the charger.
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Feb 14, 2024 18:22
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It all depends on how fast you want to iterate your designs. It's really satisfying to just have a completely finished prototype in a single day. If you design a double sided board with a very limited amount of bottom traces (that will become jumper wires if you etch the board yourself, or get fabricated as normal if you order the board somewhere) you can easily try it out. The CAD stuff takes much more time than making a board. The amount of lab stuff you need is limited. My first tiny boards i did in a 500ml beaker of etchant sitting on the lab hot plate with a stir bar in it. Only recently i made an actual etching tank that fits an eurocard, from some laser cut polycarbonate. Aquarium air pump and a glass rod i blew some holes in to bubble air through it. The etching solution stays warm enough for the time needed, so it doesn't have heating. I never bothered with UV exposing transparencies, because i often only need a single board. Using the transparancies makes it easier to create larger numbers, but if you need larger numbers i'd just order them. I have also been thinking about laser ablating etch resist, since we have a laser cutter (for plastics and wood) at work. That would be absolutely fantastic. LimaBiker fucked around with this message at 18:29 on Feb 14, 2024 |
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Feb 14, 2024 18:26
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Home etching your own boards has flipped from "this is how you get started into the hobby, but few experts will do it" to "ONLY experts will do it, you really have to know you want to do it"
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Feb 14, 2024 21:16
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Yeah, I etched my own boards a few times (using ammonium persulphate I think it was, it was much better than the "standard" acid because you could actually see through it and also it turned an extremely pleasant blue after use) and I would not recommend it to anyone. I only did it as I was a penniless electronics hobbyist about 20 years ago and though singlesided was manageable, doublesided was a nightmare (though I did get them to work) and every board you make looks incredibly home made. Instead just spend like $25 and get incredibly professional looking boards.
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Feb 14, 2024 21:37
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custom 2-layer boards have the same NRE and turnaround time as custom vinyl stickers
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Feb 14, 2024 22:18
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Big thanks to the thread for helping me with my greenhouse project a little while back. It’s coming along, and I’m getting pretty dang close to a wrap, here. The board itself:  And the ridiculous back side that nobody will ever see, especially once installed, but I love the extravagance:  Assembled (edit: pre-solder, apparently) with the socket for the rpi zero that’ll sit above the majority of the components:  An enclosure I drew up, it has mounting holes and some areas that are fully enclosed to separate all the 120VAC parts from any foreign objects and such, acting as safety baffles. I dunno, seemed like a good idea.  Everything installed, power runs in through one end there, and there’s a slot at the other end for external connections (fans, lights, sensors, etc)  Super tidy, I love it  Everything seems to be working, the pi is happy, I can control the lights when I hook them up, even seem to have gotten the polarity right on the screw terminal for the light dimmers there. Even the weird fan connectors I had to order from a guy in a trench coat behind the ihop are perfect. The only known issue is that when I dim the lights to zero, they aren’t shutting completely off, which is different from my breadboard proof, but I thiiiiink I might know what’s going on there and if I’m right, it can be addressed by leaving one specific capacitor off the board. Hopefully. If not that, then I think swapping the resistors for a different value may do it. Anyhow, like I said: thanks, y’all! Super jazzed with how this went. Bad Munki fucked around with this message at 02:34 on Feb 15, 2024 |
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Feb 15, 2024 02:23
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^^ Congrats on finishing it! Looks pretty slick in the enclosure and all. https://www.youtube.com/watch?v=AF8d72mA41M I saw this Veritasium video about blue leds. The story of how Shuji Nakamura invented it is pretty cool (too bad he got shafted by a company) and he's got a somewhat detailed explanation of how the physics work. So apparently blue leds are a really recent thing?? Like only-easily-available-in-the-1990's recent. Occasionally I wonder why I never got pretty blue ones as a kid, but it never occurred to me that maybe they actually didn't exist back then.  I gottem now though... 
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Feb 15, 2024 07:35
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Charles Ford posted:Yeah, I etched my own boards a few times (using ammonium persulphate I think it was, it was much better than the "standard" acid because you could actually see through it and also it turned an extremely pleasant blue after use) and I would not recommend it to anyone. I only did it as I was a penniless electronics hobbyist about 20 years ago and though singlesided was manageable, doublesided was a nightmare (though I did get them to work) and every board you make looks incredibly home made. I made my own board once and I would probably do it again if I needed to because there's something about me that dislikes buying services.
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Feb 15, 2024 08:30
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Rescue Toaster posted:Anyone have micro grabbers they're happy with? I've had various of the cheapo ones from aliexpress that work-ish but have slowly driven me mad or injured me. Recently I picked up a set of these from ProbeMaster. Haven't tried the micro grabbers but the rest is very good so far: https://probemaster.com/8000-series-test-lead-master-kits/
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Feb 15, 2024 13:25
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Stack Machine posted:If the phone is being powered by a charger and the charger is grounded separately from the stereo, that's a classic ground loop. You can also have AC ground loops where maybe there's not a physical connection back to ground but there's some stray capacitance between your phone or your cable and ground. Yeah it's definitely not that kind of hum, I know that one. I do think the phone is doing something fucky, seems with the right connector it might work. Need to test it in the car again.
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Feb 15, 2024 14:41
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I have an AC adapter with a USB-C output (this one) that seems to have stopped charging. I bought it at the end of November so I may be able to persuade Anker to replace it if it really is completely broken. I also have a multimeter, but I'm not sure if I'd be taking my life into my hands testing it without knowing exactly what I'm doing. I could buy a dedicated USB-C tester that would be easier to use but is there a way to use a multimeter without electrocuting myself? I haven't found any useful videos (my usual go-to for things like this) but I might not be using the right keywords.
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Feb 17, 2024 02:39
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You won't electrocute yourself on 5V, but also, you won't be able to hit USB-C contacts with a multimeter. Do you have any other USB-C devices?
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Feb 17, 2024 04:54
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His Divine Shadow posted:Yeah it's definitely not that kind of hum, I know that one. I do think the phone is doing something fucky, seems with the right connector it might work. Need to test it in the car again. Success! Or so it seems like for now. I noticed the static noise started and stopped despite the phone being plugged in, happened when switching apps or going into settings, times when the sound was likely off. So I got pretty convinced the reason for the noise is the android software and the auto-impedance matching I hear it does. I believe it simply couldn't figure out the right match because this was no headphone, it was now hooked into the amplifier input of a car stereo. Probably not at all what it was expecting. The solution turned out to be to put two 100 ohm resistors in series with each channel, along with the 1uf capacitors. Why 100 ohm, it's what I had around. I had some higher resistance too but I have a gut feeling a lower value is better or I would likely be attenuating the signal too much. I think adding the resistors make it more like connecting to a pair of head phones so the phone can do a proper match. This is all pulled out of my rear end however.
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Feb 17, 2024 10:17
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Lemniscate Blue posted:I have an AC adapter with a USB-C output (this one) that seems to have stopped charging. I bought it at the end of November so I may be able to persuade Anker to replace it if it really is completely broken. You can buy a USB-C "trigger" for $6 or less than that if you look around: https://www.amazon.com/JacobsParts-Voltage-Trigger-Module-Adjustable/dp/B08NWG1B3M/ They are little adjustable thingies that will plug in to your USB-C Anker Power Supply, and tell it what voltage they want supplied, which you can then verify by tapping your multimeter to the pads. a USB-C power delivery (PD) supply like that Anker is supposed to be able to supply 5v, 9v, 12v, 15v, and 20v as requested by the receiving side, which is what those triggers do. Those triggers are good to have in general because you can use them to add power ports to all kinds of things.
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Feb 17, 2024 10:35
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Lemniscate Blue posted:I have an AC adapter with a USB-C output (this one) that seems to have stopped charging. I bought it at the end of November so I may be able to persuade Anker to replace it if it really is completely broken. Tell Anker: "I tried it with a different cable and different phone, and it still won't charge. Please replace." No way do they want you to poke it with a multimeter and try to debug it yourself.
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Feb 17, 2024 17:46
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I just realized my Rigol scope has an Ethernet port on the back. What the hell is that for?
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Feb 18, 2024 04:56
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kid sinister posted:I just realized my Rigol scope has an Ethernet port on the back. What the hell is that for? If it's really ethernet and not them just recycling an RJ45 socket for something weird (which seems more common the more "enterprise" some equipment is) it might let you remote control it, including seeing the screen, possibly requiring some software you don't have access to. The ~1990 HP logic analyser I have was available with a network card I haven't managed to acquire yet (occasionally they pop up on eBay for twice the price I paid for the machine with probes - but occasionally a machine pops up with the card in it for about the price I paid, so I might get that for spares too. Particularly since the cards in the "mainframe" are interchangeable), and if you have that, it starts an X server so you can access it remotely like it was a Unix app, and control all the functionality from the comfort of your PC. If it's not ethernet it might just be a port for reflashing the microcontroller or something even weirder.
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Feb 18, 2024 05:12
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kid sinister posted:I just realized my Rigol scope has an Ethernet port on the back. What the hell is that for? You can control it by sending it UDP commands. I use this script basically weekly to grab screenshots: https://github.com/rdpoor/rigol-grab I also did some complicated scripting once, alongside an embedded device I was developing to get a whole bunch of data with different configurations.
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Feb 18, 2024 06:17
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ante posted:You can control it by sending it UDP commands. You mean I don't have to fiddle with a thumb drive to do a screen grab? I could kiss you.
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Feb 18, 2024 06:19
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I trigger it from across the room, even.
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Feb 18, 2024 06:25
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Hey finally installed in the car, turned out looking real well. Aux input next to cigarette lighter. Now if I'd find where I put that last plug so I can cover up the unused button space.
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Feb 18, 2024 13:03
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kid sinister posted:I just realized my Rigol scope has an Ethernet port on the back. What the hell is that for? Controlling the device. There is probably some kind of GPIB over Ethernet functionality implemented, that you can use if you find the documentation.
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Feb 18, 2024 13:32
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His Divine Shadow posted:Hey finally installed in the car, turned out looking real well. Aux input next to cigarette lighter. Now if I'd find where I put that last plug so I can cover up the unused button space. Looks real good, neat!
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Feb 18, 2024 17:48
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I'm trying to sort out typical ESP32 pinouts. I think this Whadda board is following fairly typical ESP32 pinouts: https://cdn.velleman.eu/downloads/25/prototyping/manual_wpb109.pdf But holy JPEG artifacting, Batman! It's gross to see it on there. Something I'm trying to figure out is if some pins are set aside for flash memory and can't be normally used. I've seen this come up before. I've also seen those pins come up for UART. Look at this image for an example showing them that way: https://www.teachmemicro.com/wp-content/uploads/2023/12/ESP32-pinout-diagram.jpg What confuses me is that I usually see UART1 pins all in that area, (RX1, TX1, CTS1, RTS1). However, I'll see RTS2 and CTS2 taken over as well, which just seems kind of strange. Also, UART0's CTS and RTS pins compete with VSPI ports. Yes, I know these ESP32 ports are very flexible but I was trying to keep stuff together that's labelled together. Edit: Do these ESP32 pins that are set aside mix a bunch of SPI and UART stuff together? I guess I see SPI roles for those pins too.
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Feb 19, 2024 10:54
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Use this page: https://randomnerdtutorials.com/esp32-pinout-reference-gpios/ There's a table down there with a much better description for which pins can be used for what. For things like the native SPI port - Unless you're on the bleeding edge of what the ESP32 can do, it literally doesn't matter. You pass it the pins you want in software, and the internal crossbar switch will handle it. I vaguely recall that if you're trying to maximise the speeds on QSPI, then using the native ports matter, but there are few other cases. Don't worry about it.
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Feb 19, 2024 19:16
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gently caress it, I'll ask here too: anyone got a rec for magnifying & lighting headgear that doesn't suck, but also doesn't break the bank? I'm having trouble telling the Tx from the Rx with this 2mm tall silkscreen text. Ready to go full dork.
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Feb 24, 2024 16:43
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Skinnymansbeerbelly posted:gently caress it, I'll ask here too: anyone got a rec for magnifying & lighting headgear that doesn't suck, but also doesn't break the bank? I'm having trouble telling the Tx from the Rx with this 2mm tall silkscreen text. Ready to go full dork. I have not used this brand but this is probably what you want, this visor design has been used by jewelers for a century: https://www.amazon.com/Dilzekui-Magnifier-Rechargeable-Magnifying-Optivisor/dp/B0C7LNGKLP/ They just stuck a USB-C rechargeable LED array on top and it seems to be angled correctly. No reason that shouldn't work fine.
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Feb 25, 2024 10:16
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Alright, I skimmed the datasheet (pgs 15-16) but I still don't understand: on an ESP32-C6, what is the difference between the UART and the LP UART, and then between I2C and LP I2C?
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Mar 4, 2024 06:09
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I'd like to gripe for a second about rubber wiring. Back in the 1940s before we had decent flexible plastics, cloth covered wire gave way to the first flexible total coverage material to cover wire: rubber! It worked great!... for a few decades. By now, it's hard, inflexible, cracking, falling off and dangerous. These days, it's best to replace said wires one at a time or, if you're lucky, slide heat shrink down the length and shrink those little suckers. If you enjoy monotony, you'll love replacing rubber wiring. OK, gripe over.
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Mar 4, 2024 06:11
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Skinnymansbeerbelly posted:Alright, I skimmed the datasheet (pgs 15-16) but I still don't understand: on an ESP32-C6, what is the difference between the UART and the LP UART, and then between I2C and LP I2C? Looks like it is low power, which means it works when the chip is in low power mode. I assume the other UARTs and I2C things do not work when set to low power mode.
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Mar 4, 2024 06:14
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Skinnymansbeerbelly posted:Alright, I skimmed the datasheet (pgs 15-16) but I still don't understand: on an ESP32-C6, what is the difference between the UART and the LP UART, and then between I2C and LP I2C? I'm guessing based on a quick skim of the family datasheet but I think LP stands for Low Power, available in some situation when the others are shut down.
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Mar 4, 2024 06:15
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kid sinister posted:I'd like to gripe for a second about rubber wiring. Yeah, that's why you can't use SOOW rubber cord inside walls. Rubber deteriorates pretty quickly. So what's a good 100-year insulation? I expect modern PVC will be cracked and brittle by then. Maybe PVDF?
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Mar 4, 2024 07:26
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ryanrs posted:So what's a good 100-year insulation? I expect modern PVC will be cracked and brittle by then. Maybe PVDF? At work we have a couple of rolls of teflon coated wire that are supposedly surplus from the Apollo program. The wire itself looks like it could have been made yesterday but the tin rolls it comes on are very obviously old and have 1960s-ish style design. One of our old engineers bought it at an auction then gave it to the lab before he retired and nobody has used it because nothing we work on is cool enough to warrant breaking into the moon wire stash. I'm on vacation right now but if anyone cares remind me after the 15th and I'll post some pics when I get back.
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Mar 4, 2024 07:41
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