How do microwave detectors work?
Electromagnetic energy in the range of 24.125 GHz (+ or – 50 MHz) is emitted from a point source located generally about 12 feet above a target area (e.g, curbside area or area within a crosswalk). By processing the characteristics of the energy reflected from an object (in this case, a pedestrian) within the path of the energy, the detector is able to recognize the presence of a pedestrian (via detection of his/her motion) in the target area. The detection of motion in the target area (for example, curbside) is equivalent in this case to a pedestrian pressing the call button. In either case, the result is the same; i.e., WALK, DONT WALK information is appropriately displayed to the pedestrian.