Carnegie Mellon University researchers have found ways to track body movements and detect shape changes using arrays of RFID tags. RFID-embedded clothing thus could be used to control avatars in video games. Or embedded clothing could to tell you when you should sit up straight. Researchers devised for tracking the tags, and thus monitoring movements and shapes. RFID tags reflect certain radio frequencies. It would be possible to use multiple antennas to track this backscatter and triangulate the locations of the tags.
Rather, the CMU researchers showed they could use a single, mobile antenna to monitor an array of tags without any prior calibration. Just how this works varies based on whether the tags are being used to track the body's skeletal positions or to track changes in shape. For body movement tracking, arrays of RFID tags are positioned on either side of the knee, elbow or other joints. By keeping track of the ever-so-slight differences in when the backscattered radio signals from each tag reach the antenna, it's possible to calculate the angle of bend in a joint.