1.The working principle of PIR sensor:
The human body has a constant body temperature, generally around 37 degrees, so it emits infrared rays with a specific wavelength of about 10uM. The infrared rays are reinforced by the Fresnel filter and then collected on the infrared sensing source. The infrared sensing source usually uses pyroelectric components. When the component receives the change of the infrared radiation temperature of the human body, it will lose the charge balance and release the charge outward. The subsequent circuit can generate an alarm signal after being detected and processed.

In short, the infrared sensor lamp is a kind of infrared heat radiation that
senses the human body to detect the light environment. The infrared sensing
distance sensitivity is better than the microwave. The sensitivity of the internal pyroelectric probe is reduced year by year, so that the sensing distance is shortened year by year; the stability is poor. By relying on the human body temperature and the temperature difference and movement to achieve detection, the environmental requirements are high, and the induction is completely ineffective when the temperature and the human body temperature are close. In the summer high temperature environment, the sensing range is shortened.

2.How the radar microwave sensor works:
The microwave induction lamp emits electromagnetic waves through a planar antenna and uses the Doppler principle of electromagnetic waves. Any wave has a reflection characteristic. When a moving object enters the environment of the electromagnetic wave, the waveform reflection is folded back, and the planar antenna receives the feedback. When the waveform is used, the subsequent circuit is detected by the detection trigger signal.

The radar microwave sensor is aimed at detecting people or objects that are active. As long as there are moving people or objects within the range of microwave control, the trigger can be sensitively triggered. The sensor performs the detection activity through an antenna board that performs both signal transmission and signal reception. The microwave signal emitted by the antenna can penetrate non-metallic objects such as curtains and thin walls. Microwave induction mainly reacts to the movement of an object, and thus the reaction speed is fast, and is suitable for detecting an object approaching or moving away from the microwave sensor at a certain speed. The microwave sensing module is built into the inside of the tube and is sensitive to 180 degrees. The distance sensitivity is better than infrared.

So we suggest solar street lights use microwave sensor,detect faster, father, Wider range .