The MIT Fish

 

This device is a modern day version of the Theremin interface, it gets its name from the way certain fish use low voltage
electricity as a means of sensing and communicating. The device works on the principle of transmitting an electromagentic
field which can then be sensed by four receiver aerials.
The result is that the body becomes a direct and unencumbered interface in 3D space.

MIT have developed the Fish as a research project - and are in the process of producing a commercially available version...

Details of the device and the people involved can be found at:

The principle of Field imaging

The people in the research group

Complex swiss cheese mathematics for reading a hand in 3D space via field sensing