Air Quality sensor-MQ135 is used to detect the air quality. MQ-135 gas sensor applies SnO2 which has a lower conductivity in the clear air as a gas-sensing material. In an atmosphere where there may be polluting gas, the conductivity of the gas sensor raises along with the concentration of the polluting gas increases. MQ-135 performs a good detection to smoke and other harmful gas, especially sensitive to ammonia, sulfide and benzene steam. Its ability to detect various harmful gas and lower cost make MQ-135 an ideal choice of different applications of gas detection.
It has four pins: D0, A0, VCC, GND.
We can get the output of the sensor in two ways either digital output or else analog output.
If we take the output from the digital pin then the output will be either 0 or 1 based on the air quality. If the air quality is good then the output will be 1 and if the air quality is bad then the output will be 0.
If we take the output from the analog pin then the output ranges from 0 to 1024. If the air quality is good then the output value will be more and vice versa.
The output values range can be adjusted by adjusting the potentiometer which is present on the sensor.
This sensor is suitable for detecting of NH3, NOx, alcohol, Benzene, smoke,CO2 ,etc. so in order to detect these particular gases in the air we need to read the analog output from the sensor. The analog output value will be different for every gas.
• Operating Voltage: 5V DC
• Type: Analog & Digital
• Detecting Type: Air Quality
• Sensitivity to Ammonia, Sulphide and Benzene steam
• Detecting Range: 100-1000ppm
• Can be used for pollution check and air quality detection.