Even if you hide behind a wall, MITs 3D motion-tracking tech can still see you. It can even tell if youve fallen and cant get up. Sure the tech sounds invasive, but the teams WiTrack (as its been dubbed) device is actually less intrusive than Microsofts Kinect — theres no camera watching your every move. Nor is there any wearable tech involved. Instead, the setup relies solely on a wireless network and your bodys ability to bounce back those radio waves.