MQ135 gas sensor

IT18203172/MQ-135/MQ-135.ino

+int sensorValue;
+int digitalValue;
+void setup()
+{
+
+Serial.begin(9600); // sets the serial port to 9600
+pinMode(13, OUTPUT);
+
+
+}
+
+
+void loop()
+
+{
+
+sensorValue = analogRead(3); // read analog input pin 3
+
+if(sensorValue>300)
+{
+digitalWrite(13, HIGH);
+}
+else
+digitalWrite(13, LOW);
+Serial.println(sensorValue, DEC); // prints the value read
+
+
+delay(1000); // wait 100ms for next reading
+
+}