Description
It will let you estimate the quantity of volatile organic compounds (VOCs) in ambiant air via an USB connection, as well as record it on its internal flash for later retrieval when connected again by USB.
This meter circuit has been designed so that the sensor itself can be moved further away from the USB connector by a few meters: simply split the board into two parts and solder a 4-wire cable on the designated pads.
The MEMS metal oxide sensor used in this device measures the variation of volatile organic compounds in ambiant air, and use it to estimate their concentration in ppm CO2 equivalents (relative). The sensor is able to detect alcohols, aldehydes, aliphatic hydro-carbons, amines, aromatic hydro-carbons (petrol vapors, etc.), carbon oxides, CH4, LPG, ketones, and organic acids. Be aware that the first estimation is only available 15 minutes after powering on the device.
The initial value returned by the sensor is 450 ppm CO2 equivalents (theoretical value for fresh air). The sensor measure relative variations of volatile organic compounds to provide an estimated ppm value, with an automatic baseline correction. The absolute value must therefore be interpreted with great care, as it is subject to drift. It is not comparable with the absolute value returned by a Yocto-CO2 for instance, but it has the advantage of including a broader range of volatile organic compounds than a simple CO2 sensor.
