The three main aspects of the electrical design are the switch sensor circuits, the potentiometer circuit, and the solenoid power circuit.

Switch Circuits

The switches are put in series with resistors with the digital input connected between the two elements. When the switch is off, the circuit is open, and the digital input reads low. When the switch is closed, the circuit is closed, and the digital input reads high. A schematic of this circuit is below.

Potentiometer Circuit

The potentiometer is connected directly to the handy board with the swing in the analog input. This causes the input to swing from 0-5 volts. A schematic of this circuit is below.

Solenoid Power Circuit

Because the digital output cannot supply a large ammount of current, it cannot directly power the solenoid. If the handyboard had another motor output, this circuit would not be needed. The digital output is connected to the base of a power transistor while the collector is connected to an external 12 V power source. The emitter is then connected to the solenoid. The ground of the external power supply is also connected to the ground of the handyboard so the transistor will function properly. A schematic of this circuit is below.