Have some PCB photos.
Nerd statistics:
- STM32 (STM32F103C8T6)
- USB Type C PD-chip HUSB238 (to get 12V)
- LDOs making 5V and 3.3V
- Level shifter to make the correct 25kHz 5V PWM signal for the fan
- Variable dummy load to keep power bank on (for low fan speeds)
- RGB LED to indicate power level