The MQ-6 Propane/Isobutane/LPG Gas Sensor part of the Pololu range is a highly sensitive gas detection unit capable of detecting concentrations of LPG, Isobutane and Propane gases from its surrounding environment. It is made from a combination of electrodes, chemically treated with a layer of SnO2 which increases its sensitivity. When the gas is present, the resistance of the sensor decreases. There is a heating element inside the sensor to help maintain a stable environment and ensure a longer working life. The MQ-6 uses an analog output signal which is just as reliable as a digital output signal, meaning that a microcontroller can read the signal and detect the presence of gas.