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Basic Principle and Application Benefit of Air Quality Sensor

Update: 2019-08-02 17:12 Source: LUFTMY

Now more and more families will choose to use air purifiers to purify all kinds of air pollution (such as PM2.5, dust, dust, formaldehyde and other pollution), effectively improving the air quality.Air purifiers rely on air quality sensors to achieve this effect.

Working principle

The air quality sensor is mainly used in various air purification devices, and has extremely high sensitivity to PM2.5 particles, dust concentration, dust concentration, sulfide, formaldehyde and other pollution sources. There are two kinds of mainstream sensors in the market: infrared dust particle sensor and laser dust particle sensor.

Infrared PM2.5 Sensor Module HPD05

HPD05 Infrared PM2.5 Sensor Module

Infrared dust particle sensor

Infrared sensor with an infrared light-emitting diode and a high sensitivity photoelectric receiving sensors, infrared leds emit light in particulate matter will produce reflection, photoelectric sensor by measuring the intensity of the reflected light to measure the concentration of particulates in the air, sensor output PWM signals directly, the PWM width is the current density (1 ms = 1 ug/m3).

infrared sensor

Infrared sensor Detecting Principle

Per the principle of optical scattering,the Transmitter emits light, and the light meets the dust to produce the scotch light, the high sensitive Photoelectric Receiving Sensor detects the intensity of the scotch light then output intensity signal, current which is proportional to the size and quality of intensity of the scotch light, the current is amplified by amplifier and calibrated by CPU, finally output digital PWM signal or IIC data of concentration of dust.

Laser dust particle sensor:

The laser sensor can continuously collect and calculate the number of suspended particles with different particle diameters in the air per unit volume, that is, the concentration distribution of particles, and then convert it into mass concentration, and output it in the form of universal digital interface.

Laser dust particle sensor Working principle:

laser sensor uses laser to irradiate suspended particulate matter in the air to produce light scattering, photoelectric detector collects scattering light intensity in a certain angle range, the scattering light intensity will be linearly converted to voltage, and then sent to data processing system, the data processing system take the principle of Michaelis scattering theory to deal with the datas, then the equivalent particle size and the number of particles with different particle sizes per unit volume are obtained.

infrared sensor

Limitations of air quality sensors

The air quality sensor can only detect a small part of the surrounding air, that is, the content of air particles inside the purifier. Therefore, the quality control sensor should be able to connect with the purifier through bluetooth or WiFi and act as the controller of the sensor. Such an air quality sensor can be placed in any position indoors to monitor air quality in real time.

TAGsensor manufacturer air quality sensor infrared sensor