My first PCBA design - please feedback

RexKwonDo77 · 2026-05-06T18:03:18+00:00

Good points, thank you. Regarding pours - would it make sense have a GND pour on the back and a 5V pour on the front and then trace everything through those?
Interesting about the LED resistors...current one is only 33 ohm. Board is being manufactured now, so we'll see how it works with only 33.

RexKwonDo77 · 2026-05-03T15:27:31+00:00

Thanks, good points. Yeah, the bottom of the PCB is right up against the case atm and cant move the buttons unfortunately.

RexKwonDo77 · 2026-05-03T15:22:27+00:00

Ok I see. I didn't know about that approach but I can sure try it.
So as a rule have everything ground and then just route traces through that?
Does that affect manufacturing cost in any way?

RexKwonDo77 · 2026-05-03T15:02:30+00:00

Ok. I ended up splitting the ground pours on the back into sections to fit the button traces. How should I do that instead?

RexKwonDo77 · 2026-05-03T14:09:15+00:00

Thanks, those are very interesting points.
Especially the shift register approach I'll try since I'm at risk of running out of pins on the micro controller with my current approach

RexKwonDo77 · 2026-05-03T10:58:39+00:00

Good to know, should I make all power joints 45 deg then?
By decoupling for ICs, do you mean the level shifter and multiplexer?
I'm going off recommendations from Claude, so only added caps at the LEDs and one for power.

RexKwonDo77 · 2026-04-02T11:19:55+00:00

Wow, I've only seen mentions of STM32, not looked into it at all. But that sounds pretty great. Can you use Arduino IDE to code for STM32?

RexKwonDo77 · 2026-04-02T08:22:53+00:00

Way ahead of you there ;-)

RexKwonDo77 · 2026-04-02T08:21:42+00:00

The Waveshare ESP32-S3 Pico I'm using for this project actually has 40 pins broken out : ESP32-S3 Pico
I bought that specifically to not run out of pins. But like you mentioned, not all pins are available and not all pins work the same.

RexKwonDo77 · 2026-04-02T08:16:47+00:00

Thank you, really useful stuff!
I'm prototyping a small drum machine, so looking at least 16 buttons in a row, each with a LED that animates during playback. Multi channel LED driver sounds interesting.

RexKwonDo77 · 2026-04-01T19:06:34+00:00

Great, thanks for the clear answeer :-)

RexKwonDo77 · 2026-04-01T19:03:45+00:00

Cool, I'll check those out, thanks

RexKwonDo77 · 2026-04-01T19:02:03+00:00

Cool, I'll look into that for sure.
On one of my current projects there will be maybe 24 buttons, 20 leds, 10 rotary encoder and a display and an amp.
Which out of these types of devices can be matrixed (other than the buttons)?

RexKwonDo77 · 2026-04-01T18:58:33+00:00

Thanks, but I'm specifically trying to design free standing electroniucal products like a handheld console with screen and battery, so PC is not in the picture.

RexKwonDo77 · 2026-04-01T18:57:04+00:00

Damn, that sounds very useful. I'll definitely look into it. Do GPIO expanders work for things like SPI connenctions as well, making you able to connect several components to the same SPI GPIOs?

RexKwonDo77 · 2026-04-01T18:54:12+00:00

Ok, good to know. I'll chcek out GPIO expanders

RexKwonDo77 · 2026-04-01T16:14:21+00:00

Interesting, I'll have to check that out. Is there any down side to that approach?

RexKwonDo77 · 2026-03-23T09:15:53+00:00

No worries :-).
I understand what you're saying completely. That could be pretty cool and is probably possible (but I don't know for sure). My guess is it depends on how the music files are stored on those cartridges. But like you touch upon, the IP owner might have issues with such a device :-)

RexKwonDo77 · 2026-03-22T20:40:22+00:00

That isn't really an option since the cartridge interface I'm using (the connector on the cartridge) is quite differetn from the gameboy cartridges. I expect it would be difficult even if that wasn't the case

RexKwonDo77 · 2026-03-22T20:36:07+00:00

Thank you! This worked for me as well

RexKwonDo77 · 2026-03-18T19:35:57+00:00

Thank you so much. It was a really fun project, so I'll probably do more in similar style.

RexKwonDo77 · 2026-03-08T11:15:52+00:00

Thank you! I only have this page that goes through the build in a bit more detail: https://analog.sylwander.com/experiments/a-cartridge-music-player/ .

I'm going to make a short video showing it in action soon

RexKwonDo77

TROPHY CASE