Working principle and difference between microwave induction and infrared induction
Microwave inductor, microwave inductor, or microwave radar, microwave inductive switch, is mainly realized by the Doppler effect of electromagnetic wave. Any wave has the characteristic of reflection. When a wave of a certain frequency touches a barrier, part of the wave will be reflected back. If the barrier is stationary, the wavelength of the reflected wave will be constant. If the barrier moves toward the wave source, the wavelength of the reflected wave will be shorter than the wavelength of the wave source. If the barrier moves away from the wave source, the wavelength of the reflected wave will be longer than the wavelength of the wave source, It means the change of frequency. In short, if the barrier is stationary, the wavelength and frequency will not change. If the barrier moves, the wavelength and frequency will change. Microwave induction is to transmit microwave within a certain range, and then judge whether moving objects are approaching or far away by the change of reflected wave. Microwave induction mainly reacts to the movement of objects (human bodies), so it has fast reaction speed and strong penetrability. It is suitable for detecting objects that are close to or far from the microwave sensor at a certain speed. For example, if a person walks at a certain speed through a certain place, it can be easily detected by microwave. Products based on the principle of microwave induction can effectively sense people or objects moving within one to ten meters, so they are widely used in garage entrances, factory intersections and other places.
The infrared sensor mainly works by detecting the infrared ray emitted by the human body or other objects. We all know that any object with a temperature greater than absolute zero will have thermal radiation. The infrared sensor can collect the infrared radiation from the outside world and gather it on the infrared sensor source through Fresnel lens. Pyroelectric components are usually used as infrared induction sources. When receiving infrared radiation temperature changes, such components will release charges and generate signals after detection and processing. Our commonly used sensors are mainly used to sense the human body, so they are customized according to the specific wavelength range of human radiation. The advantage of the infrared detector is that it does not emit any type of radiation, the power consumption of the device is very small, the concealment is good, and it reacts to the existence of the object, no matter whether the object moves or not, as long as it is within the scanning range of the sensor, it will react.