Surface with object detector - is used in security system and has object located in capacitive field changing if object is removed

摘要

A security system detector is triggered when an object is removed from the sensing surface. The object (3) is located on a plate which is made of insulating material (2) that has a looped conductor inset into the surface. The conductor is connected to the detector stage (6). The ground line (7) is connected to the base plate (1). A capacitive field is generated that changes considerably when the object is removed.