BURGLAR ALARM DEVICE FOR WINDOW AND GLASS DOOR STRUCTURES Russian patent published in 2015 - IPC G08B13/04 G08B13/08 

FIELD: physics.

SUBSTANCE: invention enables to determine the open state of a window or door, the closed state of a window or glass door, action on a window or door, breakdown of a window or door structure, interference and malfunction. The device is also capable of determining its own operating capacity and presence of interference preventing accurate determination of breakdown of a window structure. The device comprises a sensor for monitoring the state of a structure and a signal processing unit, a sensor for displacement of the movable part of a glazed window or door structure relative to the frame, and the sensor used to monitor the state of the structure is an accelerometer which is connected to said displacement sensor such that said accelerometer is turned on when the window or door is closed and turned off when the window or door is open. Breakdown of a window or door structure is determined by measuring the frequency of its natural vibrations based on analysis of a signal in the form of alternating voltage from said accelerometer and comparing the obtained frequency with given values for an intact structure. Breakdown of the structure is determined from the comparison results.

EFFECT: high reliability of determining the state of a window or door.

15 cl, 5 dwg