We developed compact, robust and accurate particulate matter (PM) sensor that allows remote detection of particles in open air under straight ambient light (>10 kLux) and arbitrary wind (speed and direction). The sensor operates as a particle counter and employs interferometric detection of the coherent light scattered by moving particles. Performance of the developed sensor was evaluated both in open air under typical indoor conditions and under controllable conditions inside environmental chamber with the standard test particles (size range: 0.5 μm – 6 μm, concentrations: 0 μg/m3 – 1000 μg/m3, airflow: 10 cm/s – 0.4 m/s) in comparison with the laboratory grade reference equipment. We confirmed experimentally ±10 μg/m3 accuracy within 0 – 1000 μg/m3 detection range for PM2.5 particles. To our knowledge, the sensor has smallest footprint among available dust sensors and is suitable for surface mount packaging in a waterproof case. The sensor does not require maintenance, has high accuracy and low power consumption. Due to very compact optical design (3 mm × 6 mm × 3 mm), possible applications include wearable devices (smartphones, smartwatches), smart home things (smart speakers, hubs, weather stations), robotics (vacuum cleaners, home assistants), and other consumer devices.

https://ieeexplore.ieee.org/document/9695447