How does a human infrared sensor work?

Human body infrared sensors are very common in smart home sensors. They are based on the development of traditional infrared sensors and play an important role in modern production practices. How does the human infrared sensor work? This article will take everyone to analyze it.

How does a human infrared sensor work?

Infrared sensors are measuring devices using infrared as a medium. The basic principle is to use the physical effects of the interaction of infrared radiation and matter to detect infrared radiation. In most cases, the electrical effects exhibited by this interaction are used. Such detectors can be classified into two major types: photon detectors and heat-sensitive detectors.

The infrared sensor used by people belongs to this type of heat-sensitive detector. It is called the pyroelectric infrared body sensor. It is a sensor that can detect the stationary human body. It consists of a lens, a photosensitive component, and a photosensitive circuit. Mechanical part and mechanical control part. Through the mechanical control part and the mechanical part, the infrared sensing part is driven to make a slight left-right or circular movement, and the position is moved, so that relative movement between the sensor and the human body can be formed.

Therefore, regardless of whether the human body is moving or stationary, light sensitive components can produce a polarization voltage difference, and the photosensitive circuit sends out a human identification signal to achieve the purpose of detecting a stationary human body. This infrared pyrolysis sensor can be applied to human body induction control, and achieve infrared anti-theft and infrared control integration, expanding the scope of application of human body infrared pyrolysis sensor. It is characterized in that the lens and the photosensitive element are arranged on the mechanical part.

On the common human infrared sensor, the outermost layer has a lens, which is called a Fresnel lens. Such lens is processed into many narrow and long cells, each cell covering a certain viewing angle and alternately focusing on the dual detector window. When the human body passes through the field of view, the emitted infrared light enables the dual detectors to generate alternating pulse signals, which can expand the sensor's field of vision and detectability of the target.

In addition, the lens material has a filtering function, which can block visible light and infrared light other than infrared radiation of the human body, increase anti-interference ability, and can also collect as much infrared light as possible to improve its sensitivity.

Infrared sensors are currently widely used in banks, shopping malls, hotels, buildings and other occasions. They provide great protection for consumers in terms of theft prevention and so on. They can also greatly reduce some potential safety hazards when they are used in households.

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