is a free, open-source motion tracking application designed for PC simulators (flight, racing, space sims). It uses a standard webcam and a lightweight head-mounted model (e.g., three-point LED clip or cap with reflective dots) to provide 6-degree-of-freedom (6DOF) head tracking. It emerged as a low-cost alternative to commercial products like TrackIR.
FreeTrack version is generally the most stable for Windows 7 users. FreeTrack - EyeComTec
: To ensure the camera only "sees" the LEDs, you can use a piece of developed film or a floppy disk magnetic strip over the lens to block visible light. Installation on Windows 7