A Small D.I.Y. Liquid Petroleum and Natural Gas Sensor that offers digital and analog output for Microcontrollers.
This is a small Do It Yourself kit that requires soldering to get it operational. This sensor comes with the MQ5 gas sensor that will detect for Liquid Petroleum and Natural gas.
This module also has a buzzer and LED to indicate when the sensor detects LPG and Natural Gas. Alternatively you have some header pins on the board that will provide either analog or digital signal to your microcontroller of choice.