Tiniest possible arduino

[thesko]

Recently I've discovered this design for a 0.4" x 0.4" arduino compatible board:
https://hackaday.io/project/3117-a-even-smaller-nanite

My proposal:

• a similarily sized Tinyduino, possibly powered by a small battery cell
• a neopixel addon board which can be soldered to the bottom side of the board (using spacers)

[tiresomethink]

I agree with the suggestions you have made.
8 ball pool

[Yulianes]

Recently, I came across the schematic for a tiny arduino-compatible board measuring just 0.41 by 0.41 millimeters (0.4 by 0.41 inches), called a Tinyduino, and perhaps powered by a coin-cell battery.
run 3