Ultrasonic space surveillance system esp. for closed room - has cylindrical ring mounting with foamed plastics support for screened units in metal cans with main and auxiliary sonic alarms

The device for space surveillance, without direct entry, uses an ultrasonic type detector with alarm units. The transmission and reception units are mounted in screened housings, made of metal, typically of aluminium or of a ferromagnetic material. The mounting is made on at least two annular members with cylindrical shapes and axes parallel with the cylindrical axes of the housings and equipped with flexible foamed material. The alarm system operates through the loudspeaker component of the receiver but is supported by an auxiliary unit, for example a microwave alarm signal unit. The active components of the transmission and reception units are responsive to specific function signals and have operation and test units aligned to the same functions.