Abstract: A security system includes an intrusion detector having a transmitter coupled with a portable receiver to alert a homeowner or the like that an intrusion has taken place or occurred within a pre-set time period. The area under surveillance is monitored by an infrared detector which activates the transmitter upon the receipt of abrupt differences in infrared radiation levels, associated with the presence of a warm body in an otherwise equilibrated environment. A radio signal is emitted by the transmitter upon activation by a transmitter-receiver carried by the homeowner or the like as he/she approaches the protected area. The radio signal from the transmitter is received by the portable remote transmitter-receiver. A first signal, indicating that an intrusion has been detected in the monitored areas, is displayed on the receiver for a preselected period of time.

Abstract: A security system has a flee-standing intrusion detector. The free standing intrusion detector has a transmitter coupled with a portable receiver to alert a homeowner that an intrusion has taken place or occurred within a pre-set time period. The area under surveillance is monitored by an infrared detector which activates the transmitter upon the detection of abrupt differences in infrared radiation levels, associated with the presence of a warm body in an otherwise equilibrated environment. A radio signal is emitted by the transmitter which is received by the portable hand-held remote receiver. A first signal, indicating that an intrusion has been detected less than a preselected period of time in the past in the monitored areas, is displayed on the receiver for that preselected period of time.