Lpg Detector

I have to do a project on this topic.so can someone please help me out.i want to know how it works.

The sensor consists of tin dioxide (Sn02) is heated to several hundred degrees C. When heated in the presence of combustible gases the resistance of the element of meaning will drop. The sensing element is insensitive to other gases such as cooking fumes from a gas stove or cigarette smoke. Only in the presence of combustible gases will change its conductivity. These gases are not normally present in the normal use of a stove that burns the GPL and the creation of CO2, a gas that is not detectable by this sensor. If you have a leak, LPG unburned reaches the sensor causes a measurable increase in conductivity that can be used by a circuit to trigger an alarm


The sensing element may be that as a variable resistor that decreases its resistance to the presence of LPG, LNG, propane. This variable resistor is used with other resistance forms a voltage divider that feeds the power of a source of regulated voltage. The voltage divider converts the variation in resistance to a change in voltage that can be read by an ADC or analog meter.


http://www.parallax.com/Portals/0/Downlo ...

http://www.hwsensor.com/English/products ...



Here is a piece of better data.
http://www.pololu.com/file/download/MQ6. ...