Once on your home network, they detect motion within their wide-angle field of vision.

These sensors can be worn on the legs, arms and chest to detect motion, muscle activity and vital signs.

That's because every third of a second your eye 'saccades', or snaps from location to location, a restless activity brought about by the need to detect motion.

In motion simulation, when our internal motion sensors can no longer detect motion, a washout of the motion system may occur.

For example, an occupancy sensor controlling lights in an office should not detect motion in the corridor outside the office.