EP 0013484 A1 19800723 - Alarm system and method for detecting the movement of an object away from a predetermined position.
Title (en)
Alarm system and method for detecting the movement of an object away from a predetermined position.
Title (de)
Alarmsystem und Verfahren, das die Entfernung eines Gegenstandes von seinem vorbestimmten Platz meldet.
Title (fr)
Système d'alarme et procédé détectant l'éloignement d'un objet par rapport à un point prédéterminé.
Publication
Application
Priority
- GB 7847724 A 19781208
- GB 7929297 A 19790822
Abstract (en)
Alarm system and method for detecting the movement of an object away from a predetermined position, such an object being typically an item on display in a shop or a door in a closed position. The alarm system comprises a sensing circuit (12) which includes two electrical conductors (10, 11) spaced from but adjacent each other and adjacent to the predetermined position to be occupied by at least one item (15 - 18) when in use. The sensing circuit (12) includes a signal generator responsive to the capacitance present between the two conductors (10, 11) to provide a first output condition indicative of a substantially constant capacitance value present between the electrodes due to the undisturbed presence of the item (15 - 18) and to provide a second output condition indicative of a change in capacitance value due to the disturbance of the item or items (15 - 18) present. The output of the sensing circuit (12) is received by an alarm actuating circuit (13) which causes actuation of an alarm element (6) when the output condition from the sensing circuit (12) changes significantly to cause the actuating circuit (13) to trigger due to the movement of the item (15 - 18) from its predetermined position.
IPC 1-7
IPC 8 full level
G08B 13/14 (2006.01); G08B 13/26 (2006.01)
CPC (source: EP)
G08B 13/149 (2013.01); G08B 13/26 (2013.01)
Citation (search report)
- US 3919705 A 19751111 - STENDIG JOSEPH L, et al
- DE 1121507 B 19620104 - SIEMENS AG
- DE 2323065 A1 19741128 - CORDES WERNER
- US 4091371 A 19780523 - MASON JR STANLEY I, et al
- DE 1808250 U 19600317 - TELEFONBAU & NORMALZEIT GMBH [DE]
Designated contracting state (EPC)
BE DE FR IT NL SE
DOCDB simple family (publication)
DOCDB simple family (application)
EP 79302781 A 19791204; AU 5341879 A 19791204