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Infrared Detector Classification and Working Principle Analysis

May 28, 2018

Infrared Detector Classification and Working Principle Analysis

Infrared detector is a common security product. The infrared detector is installed on the door or above the window. When someone illegally approaches the house, the alarm system will automatically alarm and send the information to the user's mobile phone. This article is to popularize the classification of infrared detectors.

Infrared detectors can be classified into passive infrared detectors and active infrared detectors according to the working principle.

1. Passive Infrared Detector

Passive infrared detector Advantages: The sensor does not emit any type of radiation signal, its power consumption is very small, concealment is good, and the cost is low. Infrared sensors are used in passive infrared detectors.


Disadvantages of passive infrared detectors: easy to be affected by various heat sources, radiation sources, passive infrared detectors poor penetration, the body's infrared radiation is easily obstructed by the object, not easily received by the detector.

2. Active Infrared Detector

The active infrared detector is a device that uses the linear propagation characteristics of light to detect intrusion. It is composed of an optical transmitter and an optical receiver. The receiver and the transmitter are installed on both sides of the door or window, respectively, at the receiver and the transmitter. A light alert line is formed between the intruder and the police. When the intruder touches this line, some light is blocked. When the receiver receives no light signal, it will trigger an alarm signal.

The human body can emit infrared rays. This infrared radiation emitted by humans is the basis for the work of infrared detectors. Infrared sensors generally use pyroelectric elements. After receiving the infrared radiation from the human body, the phenomenon of charge imbalance occurs, and the charge is released outward. After monitoring the charge change in the circuit, an alarm signal can be issued.

Infrared detectors are generally used in smart security systems and play a very important role in protecting home security. Consumers can immediately know the hidden dangers through the mobile phone when security threats occur and can handle them in time. The infrared detector can be said to be a smart home product necessary for home security.