Gas detectors are electronic devices that detect and identify presence of different types of gasses. They are used to detect toxic or explosive gasses and measure gas concentration. Gas detectors are employed in factories and manufacturing facilities to identify gas leaks, and to detect smoke and carbon monoxide in homes. Gas detectors vary widely in size (portable and fixed), range, and sensing ability. They are often part of a largerembedded system, such as hazmat and security systems, and they are normally connected to an audible alarm or interface. Because gas sensors are constantly interacting with air and other gasses, they have to be calibrated more often than many other types of sensors.