The iMPAQ iQ-PIR-IN wireless motion sensor is designed to track human movement in a guarded room. The sensor ignores pets weighing up to 20 kg. The principle of operation of the sensor is based on the determination of infrared (IR) radiation. Every living thing is a source of infrared radiation. Therefore, as soon as the sensor notices it, it analyzes the mass, and if it exceeds 20 kg, sends an alarm signal to the central alarm system unit via a radio channel (without wires). Microprocessor processing of the incoming signal provides an additional check for movement and mass, to eliminate false positives from animals. The sensor works only when a person moves. For example, if an object falls in the room, or a cat runs, the sensor will not work.