Cheap CO2 meter using the MQ135 sensor with AVR ATmegaMQ135 is an Air Quality Sensor suitable for detecting of NH3, Alcohol, Benzene and other gases. The description below, is what i derive from the poor datasheet of this sensor, it may be uncorrect, so if you have suggestions please leave me a feedback. update - Here you can find a way to estimate the correlation function of MQ sensors, and extrapolate coefficients from the datasheet curves: http://
