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A brief analysis of the working principle of PM2.5 dust sensor

Update: 2021-04-07 16:45 Source: LUFTMY Reading: ↻ News

PM2.5 sensor can also be a dust sensor, dust sensor or dust sensor, can be used to detect the dust concentration in the air around us, that is, we often hear the PM2.5 value size.Aerodynamically, dust with a diameter of less than 10μm that can enter the alveolar area is usually called respirable dust.Dust particles with a diameter of more than 10μm are mostly deposited by impact, and most of them are deposited in nasopharynx when inhaled, while dust with a diameter of less than 10μm can enter deep breathing.Most of the dust deposited in the alveoli was less than 5μm.


PM10 refers to particulate matter with aerodynamic equivalent diameter of 10μm or less in ambient air.PM2.5 fine particulate matter has a small diameter, is suspended in the atmosphere for a long time, spreads over a long distance, and usually contains a large number of toxic and harmful substances, so it has a greater impact on human health. PM2.5 can enter the lungs and blood, and if it carries germs, it will do great harm to human health.

A brief analysis of the working principle of PM2.5 dust sens

The working principle of dust sensor is developed according to the scattering principle of light, particles and molecules under the irradiation of light will produce the scattering phenomenon of light, at the same time, but also absorb part of the irradiated light energy.When a beam of parallel monochromatic light incident into the measured particle field, it will be affected by the scattering and absorption around the particle, and the light intensity will be attenuated.Thus the relative attenuation rate of the incident light through the concentration field to be measured can be obtained.The relative attenuation rate can basically linearly reflect the relative concentration of dust in the field to be measured.The size of the light intensity is proportional to the strength of the electrical signal converted by photoelectricity. The relative attenuation rate can be obtained by measuring the electrical signal, and then the concentration of dust in the field to be measured can be determined.


Dust sensor is designed to sense dust particles in the air, its internal diagonal placed infrared light-emitting diode and photoelectric transistor, their optical axis intersection, when dust airflow through the intersection of the optical axis of the intersection of the intersection area, dust reflected infrared light, reflected light intensity is proportional to the concentration of dust.Phototransistor that it would be able to detect reflected light dust in the air, even very small particles such as tobacco smoke can be detected, infrared leds emit light meets dust produced reflected light, receives the sensor detects the reflected light intensity, the output signal, according to the size of the output signal intensity judge dust concentration, through the output pulse width modulation (PWM) signal to distinguish between two different concentrations of different dust particles.


The GDS06 infrared PM2.5 dust sensor from Lefmeier is a sensor that uses optical methods to detect airborne dust concentrations (e.g. PM2.5, PM10).An IRLED intersects the optical axis of an image sensor in the sensor, and when a dust-bearing airflow passes through the intersecting region, it produces reflected light.The image sensor detects the IRLED light reflected by the dust and determines the concentration of the dust according to the strength of the output.The dust sensor can detect particulate matter such as cigarette particle size and indoor dust particles, by output different PWM pulse width watch modulation signal to distinguish, thus achieving PM2.5 and PM10 measurements.

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