METHOD AND SYSTEM OF INTRUDER ALARM Russian patent published in 2009 - IPC G08B13/12 

FIELD: physics, alarm.

SUBSTANCE: intruder alarm for closed volumes of premises such as separately standing houses, cottages, warehouses, vehicles, etc. Air pressure sensor is installed in protected room, which registers oscillations of air pressure in room in frequency bands with central frequencies of 0.1 and 0.01 Hz, at that area of 0.1 Hz corresponds to signal stipulated by intrusion of trespasser into secured room by means of ventilator window, window or entrance door opening, breaking of glass, damage of walls and ceilings, and area of 0.01 Hz - to interference from noise in case of wind action at external walls and ceilings used by logical circuit of sensor or connected to sensor by computer to make decision on fact of intrusion, and in case of vehicle protection, apart from internal sensor, external sensor is used, which is placed, for instance, under hood, for registration of interference from transport passing by, which also reacts to opening of hood to prevent vehicle theft.

EFFECT: increased noise immunity.

3 cl