Intrusion Alarm Systems > High Sensitive Sensors

PIR Detectors
Passive Infrared Sensor or PIR is a motion sensing device. It operates in two phases. First it registers the different temperature zones with respect to the ambient temperature, namely the body heat of an intruder. In the second phase it observes if the perceived temperature mass moves across the area covered by the PIR. PIR spreads infrared pulses in passive and negative modes alternatively. Any movement within the area naturally cuts the positive and negative pulses which are invisible. This pulse cutting results in a confirmed intrusion and a relay signal will be delivered to the intrusion alarm control panel for further action. All PIR units will have lines for power, relay and tamper. Hence tampering the cables or opening the PIR case results in an alarm activation. Various models available in PIR are :
 

Photo Electric Beam Detectors
Photo Electric Beams will be used to detect intrusion along the compound or perimeter walls. A transmitter and a receiver unit is mounted on the two extreme ends of the same wall (which are in straight line and with no angular deviations in between). An invisible photo electric beam will pass between the two. Anyone trying to jump the wall will cut the beam and hence an intrusion signal will be generated. Photo electric beams are available in single, dual and quad beams to suit the conditions which are dependent on the level of risk and possibility of false signals. Various models available in this category are as follows:
 

Magnetic Contacts
Magnetic Contacts will be placed on doors. When activated they produce a magnetic field between them. This magnetic field will be broken when a door is opened as one of the contact will be fixed on the door frame and another, on the door itself. Depending on the application, they again are divided into two categories: