Vibratory and ultrasonic fence intruder detection system

Claim 1

In combination with a fence enclosing an area to be protected against intrusion and supported by a plurality of spaced rigid, substantially vertical fence posts, an intrusion detection system comprising: a plurality of sections of relatively rigid electrical conduit supported on and in contact with the fence serially therealong and independently of the fence posts so that relatively small vibrations of the fence cause vibration of the conduit in contact therewith; a plurality of housings, each interposed between and having a connection with two adjacent sections of the conduit so that the sections are serially connected together by the housings; a vibration sensor secured in each of the housings and responsive to vibrations transmitted to the housing in which it is located, each of the vibration sensors being effective to produce a vibratory electrical signal in response to the conduit being vibrated; an ultrasonic intrusion sensor mounted in each of the housings for sensing changes in ultrasonic waves resulting from movement of an object in a zone proximate the fence, each of the ultrasonic intrusion sensors being effective to produce an output signal in response to said changes; an indicating device; first connecting means operatively connecting a group of the vibration sensors to the indicating device; and second connecting means operatively connecting a group of the ultrasonic intrusion sensors to the indicating device; whereby the indicating device in response to said vibratory signals and/or said output signals, indicates an intrusion.