DYIer Steve Hoefer has created quite an interesting device.  Upon tapping a correct sequence and rhythm on a door this Arduino board-based device will unlock a dead-bolted door.  After artfully smushing together a microcontroller, a piezoelectric speaker, a gear reduction motor, and some PVC pipe Hoefer posted his dramatic results in the video above.  Neat, huh?

[Via Engadget]