The Adjacent Reality open source wireless head/hand Tracker : http://www.mtbs3d.com/phpBB/viewtopic.php?f=138&t=15184

https://twitter.com/AdjacentReality

From Wikipedia :
The latest version includes Oculus' new 1000 Hz Adjacent Reality Tracker that will allow for much lower latency tracking than almost any other tracker. It uses a combination of 3-axis gyros, accelerometers, and magnetometers, which make it capable of absolute (relative to earth) head orientation tracking without drift.[15][20]

http://eclecti.cc/computergraphics/snow-globe-and-the-adjacent-reality-tracker

http://eclecti.cc/tag/adjacent-reality

http://www.roadtovr.com/2012/10/25/oculus-rift-headtracker-adjacent-reality-1695

http://adjacentreality.org/

http://adjacentreality.org/NodeHardware/

https://github.com/AdjacentReality/NodeHardware