Using an IR led array and some reflective tape, you can track fingers in thin air using the Wii Remote by Johnny Chung Lee, Carnegie Mellon University. The grid software is a custom program written using a C# wiimote library and DirectX. More information about the grid software can be found at http://www.cs.cmu.edu/~johnny/projects/wii/

Carnegie CMU computer finger human interaction Johnny Lee Mellon minor remote report tracking University wii wiimote