Beacon Devlog #7: PRIMARY PCB COMPLETE!

This one took about 20 hours, so I’ll go over the primary setbacks here:

• initial schematic didn’t really consider high threshold voltage of warm white LEDs - trying to power them off of the primary 3.3v rail would result in manufacturing differences just killing some of them most likely. I instead connected the MOSFETs which power the breakouts directly to the battery regulator voltage, which should hover closer to 4V.
• A couple of my components (e.g. a 3.3v i2s MEMS microphone) had faulty footprints when downloaded through vendors like DigiKey, which took me embarrassingly long to work out
• My last post shows a comical amount of errors: these stem from many of my footprints for smaller components (e.g. TVS diode array) having small pads with low distances between each other. I downloaded custom design rules for JLCPCB without really understanding what they did, and had to shuffle with them a bit to get round the 300 warnings (down to about 9 now, I think they’re safe to ignore)
• Finding suitable headers for the breakout boards (the 2 8-pins at the top) took a while, given how little room I’m working with. Every connector on the board posed a major routing challenge until I realised that I could change my schematic in response to a dead end on the PCB. On a related note, I’m mixing and matching connectors here to fit the few components I already own (e.g. standard 2.54mm headers for my E-Ink)
• Working out differential pairs was less than fun
• About 4 hours of work didn’t record while I was working out how to use an old spare monitor with my laptop: not the end of the world, but a shame

This is my first project with KiCad: the resolution’s not great, but if you spot any issues please mention them

What’s Next

Before I apply for funding, I need to make a 3D model of the enclosure, design the LED breakout boards, and make a proper GitHub repo out of these.

I hope to have that done in the next 5 days or so, so I can focus more on school when it starts up again.

When it’s done, hope you guys give it a try!