When particulate matter in the air obstructs this beam, the infrared light undergoes diffuse reflection; the phototransistor subsequently detects this reflected light, causing a corresponding change in the voltage at the signal output pin Serving as the core detection component, the sensor operates based on the principle of infrared light scattering. It is capable of detecting suspended particulate matter in the air-such as dust and -with a diameter 0.8 microns The sensor features a central aperture that allows for the free circulation of air. An infrared light-emitting diode (LED) and a phototransistor are mounted at adjacent internal corners; the infrared LED emits a directional beam of infrared light Within a specific range, this voltage value exhibits a linear relationship with the dust concentration; therefore, during operation, an Analog-to-Digital Converter (ADC) is required to sample this voltage signal, thereby enabling the calculation of the dust concentration in the air based on the measured voltage value, Weight: 0.05842249943 Pounds, Manufacturer: Teuypty