Simco, Inc.

John E Pfeifer

Stanley I Mason, Jr

An intrusion alarm is encased within a housing hung from a doorknob by a conductive strap which makes electrical contact with the doorknob apparatus. A monitoring circuit within the housing is connected to the hanging strap for sensing capacitance changes corresponding to touching of the exterior portion of the doorknob apparatus by a would-be intruder. Alarm means within the housing are activated by the monitoring circuit to generate a local audible alarm or an FM transmission signal sent to a remote receiver or both. A latching circuit maintains the alarm means in an activated state after the capacitance coupled to the doorknob apparatus has been removed, and switch means on the exterior of the housing are provided for resetting the alarm to a non-activated state to permit sensing of a subsequent capacitance change. The alarm further includes means for temporarily disabling the alarm device for a predetermined period of time during which it may be touched without activating an alarm signal. A status indicator is included to provide a flashing signal when the device is actuated and the batteries are supplying power.

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Weston, CT, United States of America

John E Pfeifer