E/CS 53 was my first independent project class. I built a 68HC11-based "power puncher", capable (somewhat) of automatically opening the type of combo locks that are on all the doors at Caltech. It mechanically punches in all possible combinations, testing the latch and determining what the combination is to the room. Solenoids are used for punching the buttons, a stepper motor turns the latch, and there is an LED display and a rudimentary user interface.