Security apparatus

摘要

The apparatus is for detecting interference with an object e.g. a vehicle 1 and comprises a plurality of detectors e.g. ultrasonic range finding detectors 2-11 on the vehicle and directed towards its wheels or the ground. They register a different output if an unauthorized object is passed through their beam. Such detection is memorized in a central unit 13, and its occurrence is indicated on the unit when the latter is interrogated by a remote unit 17.