This is an interesting project that uses an old CD-ROM drive to make a CD-ROM Door Lock. Granted the system isn’t very secure however it would be trivial to connect it to a real deadbolt. It sounds like the system is voice activated but it is just the inventor asking his son to control the system while it was being recorded.

"The circuit board in the middle is an H-bridge circuit I built to allow the motor to move in both directions. There are two position sensing switches so the Arduino senses when the motor has reached its limit in either direction. A 9V power supply powers the Arduino board, and a separate 5V supply drives the motor through the H-bridge. The dead bolt is literally a bolt — connected to the assembly with a piece of scrap circuit board — that travels through the door jamb and into the door."

Arduino-Controlled Lock from nootropicdesign on Vimeo.