As a Christmas gift for 2025 I made some PCBs in the shape of a Christmas tree to give to friends and family as little presents. They took quite a while to design!
I designed the PCB in EasyEDA.
There is one ATTiny-3217 that drives the main system, decides what patterns to show on the LEDs, etc.
The LEDs are driven by four IS31FL3731s, I used four because each one can only support 144 LEDs, and I thought this was not nearly enough LEDs. Also, because of different electrical properties of the different colour LEDs, it was suggeted by the datasheet to have each chip only drive one colour of LED, though I didn't discover that until after the first prototype (it had a lot of cross talk and some LEDs would often come on then they weren't supposed to).
Each chip is meant to drive two grids of LEDs and these were really fiddly to wire up the right way.
In the image below you can see how I laid out the main part of the board.
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