So when I flash the code to these, I check that the LEDs all light up (which is why I put that little power on flourish in the code). But even then, it’s probably the most likely issue with these boards. Almost every QC failure has to something to do with them.
It’s totally my fault, but I think I had a good reason, let me explain:
So when you normally use these WS2812C-2020-V1 Addressable RGBs, and want to place them at a 2.54mm pitch, this is how you’re supposed to place them on the board:
Notice how the contacts are nice and far away from one another? There’s much less risk of shorts this way (this is how they’re arranged on the wishbone board.)
But because I wanted to be sure these domes slot nicely into the holes in the bottom of the breadboard clips, I arranged them 90° from the recommended way like this:
This helps the light diffuse in the breadboard rows, so it’s not just the middle hole lit up and the rest kinda dark. But that kinda creates a potential problem:
Those being so close together creates a lot of opportunities for shorts. I also suspect the PCB fab recognizes this and puts less solder paste there, which can also cause the opposite problem of them not being fully soldered down. This is much more likely to be your issue, because I’ve tested every board before it got to you, so for it to be intermittent like that, it’s probably a not-fully-soldered LED.
So I’m going to put up some general things to try when your LEDs are doing something like this
These are addressable LEDs, so each one takes in data and then actively passes it along to the next one. So if you have this problem, you can find which LED is being a dick by looking at this and seeing where the signal stops being passed along.
To start, we should be able to see when your troubleshooting efforts have worked, so here’s how to get to the Rainbow Bounce Test
That will make the LEDs continuously run the startup sequence.
The first thing you should try with a bad LED is to get one of those extra long pin headers (or something similar) and stick it in the middle hole of the first LED that’s not coming on and kinda press down on the LED to see if it does anything.
If that doesn’t do anything, try the same thing with the last working LED. Your problem is with one of those two.
Whether that works or not, the next easiest thing to try is to reflow the solder in just that area. So with the long headers in both of the potential problem LEDs, heat up the back of the board in just that area with either a hot air gun or a soldering iron. It’s gonna take a lot of heat, but if this works, you’ve saved yourself a ton of effort.
The next escalation is to remove the top plastic shell, you can do this without desoldering the clips, it’s just gonna take a lot of force. Start at the feet in the corners an shimmy it up slowly from each corner. If you need to pry against the board, be careful not to cut the traces on the front of the board while doing it (ask me how I know.)
Or if you’re really good at it, desoldering all the clips will work too.
Now that the board is free, desolder just the spring clips covering the 2 potential problem LEDs and try to reflow them from the front.
If they’re just totally dead, you’ll need to replace them. You can either ask me for some spares or just buy a few.
Or if by now you’ve given up, you can always send the board back to me and I’ll fix it for you. Just send me a message and I’ll send you a shipping label.
Anyway, I hope this helps with some LEDs issues you might be having. Feel free to post pictures of your specific issue and I’ll help you with getting it figured out.