This example is for Wiring version 0024+. If you have a previous version, use the examples included with your software. If you see any errors or have comments, please let us know.
Air Quality MQ135 sensor by BARRAGAN
Reads values from an air quality sensor connected to the analog input pin 0. The value read from the sensor is proportional to the air quality measured by the sensor. The value read is printed through the serial to be monitored in the console.
Reads values from an air quality sensor connected to the analog input pin 0. The value read from the sensor is proportional to the air quality measured by the sensor. The value read is printed through the serial to be monitored in the console.

int val; void setup() { Serial.begin(9600); // sets the serial port to 9600 } void loop() { val = analogRead(0); // read analog input pin 0 Serial.print(val, DEC); // prints the value read Serial.print(" "); // prints a space between the numbers delay(100); // wait 100ms for next reading }