Surveillance system for objects or rooms - uses several capacitive circuits connected via evaluation circuit to display or alarm

摘要

The surveillance system is used for protecting an object or room and employs a number of capacitive circuits. The latter are connected to an evaluation circuit (MEI) for monitoring capacitance variations, indicating in alarm condition, with a display (A) or alarm device connected to the evaluation circuit (MEI). The capacitance is provided by a number of partial capacitance, each geometrically associated with a protected object (U1, U4) so that any disturbance of the latter causes the partial capacitance to vary. Pref. each capacitance circuit employs an oscillator (O1, O2, O3, O4) with the oscillators connected to the evaluation circuit (MEI) via a multiplexer (M1).