littleBits Electronics Pressure Sensor
This is one individual littleBits bit:
The pressure sensor is a touch-activated module; give its pad a little squeeze to activate it. The more pressure you apply, the more signal it sends out. Put it in front of a vibration motor to control how much it shakes!
What's littleBits? littleBits is an opensource library of electronic modules that snap together with magnets for prototyping, learning and fun.