Piezoelectric elements can be used to make sound or detect sound. Steve Hoefer has made a Knock Lock, which is a device that can listen to knocks on the door.
Vacuum Tube Prototyping Design Board2009.11.20
Another stationary bike VR rig2009.11.20
Axe your camera (again!)2009.11.20
Software for designing circuits2009.11.20
DIY vacuum tube prototyping board2009.11.20
Marble Maze that is Remote Controlled using an Accelerometer2009.11.19
Outerspace: reactive robotics2009.11.18
LIS331AL – ADXL322 Accelerometer benchmarks2009.11.18
Build a Seismic Reflector2009.11.18
Argh, thar be a big wheel2009.11.18
