The new Kinect, released a few days ago, uses an infrared light to illuminate whatever is in front of the sensor, and the pixels of an infrared camera watch for each pulse to reflect back. Just like radar, distance is calculated by the time it takes for light to reach a particular pixel and reflect back.
The new Kinect can process 6 people at a time and, instead of the wire-frame skeletal tracking from the past, can now track fingers, muscle and force, facial expressions, joint orientation and do it all in light or dark and without distortion from side or inconsistent light sources.
It took a few months for hackers to make use of the previous Kinect for robotic apps. With so much added to the new version, robotics is sure to get a major boost from this new Kinect.