A quick update on the power controller schema. The updates:
- The first version showed relays connected directly to the Arduino. In this version, the relays are properly connected; with a flyback diode (to prevent current flowing back when the coil in the relay is discharged). And a transistor to prevent drawing too much current from the arduino pin.
- To detect if the pinball machine is still switched on, the previous schema used a +5V DC line from the PC PSU on an analog input on the Arduino. While that may work, it is better to keep the PC PSU electronically disconnected from the power controller. Instead, a photoresistor will “look” at the PC Power LED (that I will take out of an old PC case) and detect if the PC is on or off that way.
The new diagram: