The Geneva drive
is a classic way to convert continuous rotary motion into intermittent rotary motion. Usually, homemade demonstrations are done with 3d-printed parts, but I wanted to try incorporating a circuit.
The theory of operation is simple: An LED acts as the "pin" that pushes the slotted Geneva wheel along. Either a 5mm RGB LED, or a 3mm single-color LED for the proof-of-concept. A spacer underneath the Geneva wheel periodically closes or breaks a connection that then goes to the LED cathode(s).
Does it work? Nope! Well, not yet at least. I may try ordering the boards again, with no soldermask around the contacts. But I'm in no hurry.
Let me know if you have ideas or suggestions! Should I put little solder daubs on the exposed traces, or will that create high/low spots and make things worse?