I had to build a blinking device as a Proof of Value (PoV).
The concept is quite simple:
- The device should blink in green during 2 hours,
- After two hours, the device should blink in red,
- After two more hours, the device should stop blinking,
- The time counter can be reset with a magnet near the device.
- The device had to be as small as possible, as it should be wear and visible.
I chose the components, made the PCB layout, write the code, and built the case with my 3D printer.