For Electric field proximity sensing with the TI-MSP430 Microcontroller (MSP430F2013, specifically).
A simple circuit with two pieces of copper foil can be used to detect the distance of someone's hand.
Two different methods: Time-division Multiplexing (TDM) and Code-division Multiplexing (CDM).
A processing patch which displays a gui depicting the distance of the user's hand in real time is included.