Detection of Methane by Infra-Red Measurements

摘要

A low cost optical sensor for methane detection is described. This sensor was designed to give an alarm when the methane concentration reaches a level close to the LEL (Lower Explosive Limit) that is 5percent vol.for methane. An IR-LED is used as optical source which allows to construct a device without mechanical chopper and optical filters. The sensor shows a threshold concentration of 2percent methane with a signal to noise ratio of 10.