This gas sensor is suitable for detecting LPG (composed of mostly propane and butane) concentrations in the air. You can adjust the sensitivity with the potentiometer.

Specification

• Type: Analog MQ6
• Power supply needs: 5V
• Current: 100mA
• Pin Definition:  1-Output  2-GND  3-PWR 

Document

• Datasheet

Wiring：

Test Arduino Code:

void setup()
{  
    Serial.begin(9600); //Set serial baud rate to 9600 bps
}

void loop()
{
    int val;
    val=analogRead(0);//Read Gas value from analog 0
    Serial.println(val,DEC);//Print the value to serial port
    delay(100);
}