Dheera Venkatraman have decided that using keys is boring and obsolete. So he managed to build electronic door unlocker.
He used PIC16F630 microcontroller attached to PS/2 keyboard and stepper motor to slide the head. Keyboard is placed outside the door. When 5 correct numbers are pressed – the door unlocks itself. Circuit and C program is available if you want to modernize your college dorm room.