MQ-9 CO Carbon Monoxide methane liquefied Gas Sensor

Features:
Good sensitivity to CO/Combustible gas* High sensitivity to Methane, Propane and CO* Long life and low cost* Simple drive circuit
Connection here are the connections for my sensor


Arduino Gas Sensor
5V VCC
GND GND
NC DOUT
Analog A0 AOUT

Code:
void setup()
{
Serial.begin(9600);
}

void loop()
{
float sensorVoltage;
float sensorValue;

sensorValue = analogRead(A0);
sensorVoltage = sensorValue/1024*5.0;

Serial.print("sensor voltage = ");
Serial.print(sensorVoltage);
Serial.println(" V");
delay(1000);
}

Results:
Again look at the serial monitor, you need to let the sensor stabilise. Remember it consists of a heating element, so you effectively have to let the sensor ‘heat up’.
Sensor voltage = 0.40
Vsensor voltage = 0.40
Vsensor voltage = 0.40
Vsensor voltage = 0.42
Vsensor voltage = 0.41
Vsensor voltage = 0.41
Vsensor voltage = 0.41
Vsensor voltage = 0.41
Vsensor voltage = 0.40 V