Lumitrack is a motion capture technology developed by Robert Xiao, Chris Harrison and Scott Hudson at Carnegie Mellon University. It combines projectors and sensors to provide high-fidelity motion-tracking. These types of sensors are used in video game controllers, such as Microsoft's Kinect, and in motion capture for movie and television production.
Although the research prototype of Lumitrack currently uses visible light, it could be adapted to utilize invisible infrared light. According to the university, the sensors require little power and should be cheap to mass-produce. They could even be built into smartphones.