The sensor adopts the principle of laser-scattering.The scattered light is collected at a certain Angle to obtain the curve of the scattered light intensity changing with time.Furthermore, the microprocessor used the algorithm based on MIE to obtain the equivalent particle size and the number of particles with different particle sizes per unit volume. Data interface: 2 pins are serial data communication interfaces, which adopt general asynchronous transceiver protocol (UART);1 pin is the control signal interface, using high and low level control, the average of all electricity is 3.3VTTL level. Note: SET=1 module works in the continuous sampling mode. After each sampling, the module takes the initiative to upload the sampling data. The sampling response time is less than 600 milliseconds, and the data update time is less than 2 seconds. SET=0 module enters low power standby mode PM2.5 sensor How it works: laser-scattering Measuring diameter: 0.3-1.0um 1.0-2.5um 2.5-10um Measurement unit: /m3 Measurement accuracy: /m3 Response time: Less than 10s Working current: 5V200ma@ working status 5V2ma@ standby status Data interface: Serial port (3.3VTTL level) Material: metal shell colour: blue Package Contents: 1 x Gas Sensor Module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.