The MQ-6 module is used in gas leakage detecting equipment in family and industry. This module has high sensitivity to LPG, iso-butane, propane and LNG. It can also be used to detect the presence of alcohol, cooking fumes and cigarette smoke. The module gives out the concentration of the gases as an Analog voltage equivalent to the concentration of the gases. The module also has an on-board comparator for comparing against an adjustable preset value and giving out a digital high or low. It can be easily interfaced with your Arduino or Raspberry Pi.