An LPG gas sensor is a one kind of device which is used to sense the presence of a hazardous LPG gas leak in service station, cars, storage tanks and homes.This sensor is attached to an alarm circuit to give an alert to the operators through a buzzer sound in the area where the gas leak is occurring. The LPG gas sensor is also used to detect cigarette smoke,toxic gases, combustible, propane, iso-butane and LNG