Arrangement in order to prevent false alarms of a passive infrared motion alarm

摘要

In an infrared motion alarm an optical filter arranged in front of an input of an infrared detector is attached to a heat sink in the form of a solid metal crucible in order to reduce the sensitivity to glass- penetrating electromagnetic radiation. Changes in radiation absorbed in the optical filter are either captured in the thermal sink or decelerated at least as to the characteristic thermal radiation of the optical filter and no longer fall within the characteristic range of change of the motion alarm.