Infrared intrusion detector (sensor) mainly includes active infrared detector (AIR) and passive infrared detector (PIR). The principle of working theory is different for both kind of detectors. Active infrared Detectors are using dual beam transmission as structure, one side with transmitter for emitting infrared ray, the other side with receiver for receiving the ray, it is suitable for the outdoor point to point intrusion detection. Different from active infrared detector, the passive infrared detector doesn't emit the infrared ray, it receives the infrared ray that is emitted by objects.
The active infrared detector with professional name: Photoelectric Beam Detector, it consists of alignment hole, beam strength LED indicators, spherical mirror, LED...etc.
The working theory is infrared LED emits the infrared ray, then infrared ray get focused when go through spherical mirror and becoming infrared beam, after transmit long distance, the receiver accept the infrared beam. When the beam is cut (break) by the objects, then it will trigger the alarm.
Due to infrared beam with cone spread effect, the active infrared beam detector can not transmit long range distance. As our experience, it's reasonable to place (install) infrared beam detector in the distance of 20-300 meters.
Passive Infrared Detectors are looking the changes of infrared energy level that caused by movement from objects (human, pets...etc).
Some suggestion about installation of PIR motion detection and active infrared beam detector:
A. PIR Motion detector is very easy interfered by the varies of heat sources, and sunlight, so PIR Motion detector is more suitable for the indoor movement detection which in the closed environment.
1. PIR Motion Detector should not be installed near the Air conditioner places where with cold wind or hot wind flow, because PIR motion detector is sensitive with the temperature changes of environment. Environment changes quickly will cause false alarm.
2. PIR should not be installed facing the glass window, facing glass window will interfered by the outside sunlight and moving objects (people or vehicle). The infrared energy can penetrate the glass window.
3. PIR should not be installed facing the moving objects or background changing objects, movement object will cause airflow change, it may cause false alarm.
4. Between the detection range of PIR Motion detector, there is should be less objects. Many objects may reduce the sensitive of detection range.
5. Do not install more than one (2 or above) Wireless PIR in the same detection space (like at the same room).
6. After installed the PIR motion detector, installer should walk S steps in the detection range for checking the PIR Motion detector.
B. Active Infrared Beam Detectors are mainly install outside, duo to it adopts transmitter and receiver theory for detection, it's must important that beam can go through the detection area and reach to receiver.
1. Don't install active infrared beam detector near the place where with strong fog (smoke), heavy fog can interfere Active infrared beam detector (AIR) seriously, it's better to choose active infrared beam detector with AGC design which can reduce the interference that is caused by fog.
2. When using active infrared beam detector for outdoor installation, it's must that use the dual beam or 3, 4 beam active infrared detector, muti-beam active infrared detector can reduce the false alarms that are caused by bird, pet, leaf...etc.
3. Choose the active infrared beam detector which use the LED infrared wave length 0.9um.