Motion Detectors for movement detection

Motion detectors are one of most widely used intrusion detection device for alarm system.  Now there are four kinds of motion detector that most of companies are providing; Active Infrared Motion Detector, PIR based Motion Detector, Microwave Motion detector, PIR + Microwave Motion Detector (Dual Technology).

What's Active Infrared Motion Detector ?

Active infrared motion detectors are adopts invisible infrared beam transmitting and receiving theory to detection the intruder. The detector come with a pair that consist of transmitter (emit infrared beam) and receiver (receive the beam from transmitter).When intruder cross the beam between transmitter and receiver, the alarm will be triggered.  Due to reduce the false alarm, many Active infrared motion detectors adopt dual beams, triple beams, as well as quad beams technology. For example, only intruder cross the dual beams simultaneously, the alarm will be triggered, cut one beam, the alarm will be not triggered. Active infrared motion detector can install inside and outside.

What's PIR based Motion Detector ?

PIR based motion detectors do not emit any infrared beam or ray, it only receive the infrared from moving objects. The detector will be trigger, when it detects the infrared changes from detection area. Owning to PIR based motion detector are very sensitive on the temperature changes, so it mainly installed indoor. There are several PIR based motion detectors like DG85 that consist of 2 separate PIR motion sensors inside of housing for detection of the movement and reduce the false alarm. We call these detectors are Dual Sensor PIR motion detectors.

What's Microwave Motion Detector ?

Micro-wave motion detectors emit microwave energy that fills the detection area. When there is movement objects, it will disrupt the microwave, then detector will be triggered. The drawbacks of using microwave motion detectors is the microwave can penetrate most of types of surfaces (metal is not among them). Therefore, the detector may detect movement that detection is not desirable. If you live in high density living area, then you may not consider the microwave motion detectors, as someone in the neighboring apartment may trigger a false alarm. Due to metal can shield the microwave, then the detection area with big size of metal may form an blind detection spot.

What's Dual Tech  or Tri Tech Motion Detector ?

Installation movement detectors outside may interfered by the weather changes, such as wind, direct sunshine, flying birds, or small animal. Detectors may trigger false alarms when under these environment, so most of motion detectors are allowed to install inside. But installation motion detectors interior only can detect movement inside when intruder break in, can not keep the intruder out of house.

PIR + Microwave Motion detectors combined the PIR detection technology and Microwave detection technology (Dual Technology). The Dual technology motion detector consist of two separate sensors in the housing; PIR-motion sensor and Microwave sensor. The alarm will be triggered only when these two sensors are detecting the motion. Dual Technology Motion detectors overcome the disadvantages both of PIR-based motion detector and microwave motion detectors. It is widely used indoor and outdoor movement detection. Tri-Tech motion detector means PIR + Microwave + DSP Digital Signal Processing Technology.