The measuring principle of our micro-dust sensors is the detection of the scattered light from a collimated laser beam within an interaction chamber. Each sensor consists of the optical chamber and a control board.
The board is equipped with a micro-processor which performs the measurement and transmits it to any external control unit via serial communication (USB or RS-232 protocol). For complete operation, the sensor simply requires a serial connection, power supply, and a suitable pneumatic hose circuitry to allow the air under test to flow within the chamber. In order to select the particulate matter dimension (PM10, PM5, PM2.5) the sensor should be coupled with a selecting filter, either of the porous, impact or centrifugal kind ( cyclone dust collector).
Recently the Laser scattering cell and the microcontroller board have been re-engineered to be more compact, less power consuming, and compatible with 3.3/5V battery or USB power supply. They are now completely enclosed in a sealed ABS 10x10x10 cm3 box.
For further details see: Technical Note
To see an example of real-time environmental monitoring application: www.pm2.5firenze.it
Example of PM2.5 measurement in air:
These sensors are also indicated to measure smoke densities in furnaces and stove chimneys. The graph reported below shows a recording of the smoke density in a stove chimney for a time interval of approximately 30 minutes. The peak corresponds to the occurrence of a wood chunk fracture in the stove chamber, with a consequent sudden flame reduction.