With this library you can obtain ppm for every MQ135 detectable gases
The way is simple, only imports the library to your .ino source code
#include <MQ135.h>
Instantiate the object
MQ135 mqSensor(A0);/*Where A0 is the analogic input pin 0 where the output(analogic) of the sensor is A0*/
First you need the resistance zero, leave the sensor connected 24hrs outside and obtain it for each gas with this methods:
float getRZeroCO(); float getRZeroCO2(); float getRZeroEthanol(); float getRZeroNH4(); float getRZeroToluene(); float getRZeroAcetone();
Call them with
> ```
float resistanceZero = mqSensor.getRZeroCO();
Change the resistance zero in
MQ135/MQ135.h
Get the resistance (in void loop method)
float resistance = mqSensor.getResistance();//resistance
Get the gas reading
float co = mqSensor.getCO(resistance);//co ppm float co2 = mqSensor.getCO2(resistance);//co2 ppm float ethanol = mqSensor.getEthanol(resistance);//ethanol ppm float nh4 = mqSensor.getNH4(resistance); //NH4 ppm float toluene = mqSensor.getToluene(resistance); //toluene ppm float acetone = mqSensor.getAcetone(resistance); //acetone ppm