Arduino Controlled Can Crusher With LCD Readout.

Step 8 Part 7: Attaching an external power supply and finnishing up

Find an old 12v power supply that meets the needs of the motor and doesn't exceed the limits of the motor controller, and wire the positive to pin 16 of the motor controller and the negative to pin 4, 5, 12, or 13 of the motor controller. The Wire should be fed through the wire wrap and into the control box.