Multifunction occupancy sensor

Abstract

A multifunction passive infrared occupancy sensor functions as an occupancy sensor for security systems and also as an occupancy sensor for energy management control systems. The occupancy sensor comprises at least one segmented infrared lens array wherein the segments of the infrared lens array establish different optical lobes in the field of view of the occupancy sensor. At least one pyroelectric infrared detector is positioned at or near the focal point of the segmented infrared lens array, for detecting movement of infrared sources within the field of view of the occupancy sensor and producing an output signal representative thereof. A processing means analyzes the output signal of the detector for security detection purposes by detecting changes in the output signal greater than a given security threshold. The processing means also analyzes the output signal of the detector for energy management purposes by detecting changes in the output signal greater than a given energy management threshold, which is less than the security threshold. In one embodiment first and second processing circuits detect changes in the detector output signal greater than the security threshold and energy management threshold. In a second embodiment the output of the detector is coupled to an analog to digital converter, the output of which is coupled to a digital processor which utilizes one of two different software processing routines, a security threshold processing routine, and an energy management threshold processing routine. A further embodiment electronically switches detector elements in a detector element array.