Analysis on the characteristics of three common human body sensing technologies

　　1. Infrared induction: The principle of pyroelectric infrared induction is adopted. The sensor action is triggered by collecting the changes of infrared energy. Affected by the ambient temperature, when the ambient temperature is close to the human body temperature in summer, there is no change of infrared energy when people enter the sensing range, so the human body induction performance is very insensitive in summer. Disadvantages: It is greatly affected by the ambient temperature, and the infrared probe part needs to be exposed. The overall beauty of the product is not high. Advantages: it is cheap

　　2. Doppler microwave induction: the common frequency bands of 5.8G, 10GHz, 24GHZ are based on the Doppler principle. If a moving object enters the induction range, the radar signal waveform will be changed, thus triggering the action of the radar sensor; Features: It can only sense the movement of people, and can penetrate the plastic hidden installation, which is more beautiful; Disadvantages: unable to sense people in the state of meditation and sleep.

　　3. PCR radar sensor sensing: operating frequency band 61GHZ, the principle is high-precision micro motion detection, which can detect human respiratory signals. Features: it can penetrate the plastic shell, detect the moving human body, and detect the static or sleeping people. This technology is the most advanced generation of human body sensing detection technology.

Read recommendations:

NTC thermistor linear control circuit for fan speed based on room temperature.Pyroelectric infrared

NTC electronic temperature Hygrometer.Human Body Infrared Temperature Sensor

2210 PIR lens

PIR Lens 7709-1

Digital PIR Sensing Controller 3312-3s