Explosions and fires resulting from gas leaks, unfortunately, are not uncommon. Recognizing the work of administrative bodies and emergency services, hams designers can do something yourself to minimize this danger. However, in the field of gas control is simple and accessible to a repetition of the device is almost there, or they are unnecessarily expensive.
There are industrial sensors, converts the gas concentration to voltage, current, resistance and other parameters. The ability to respond to changes in gas concentration have some oxides, especially the SnO2 — tin dioxide, doped various additives. On their basis it is possible to make an electronic device that responds to the excess concentration of a particular gas in air and emits sound signal.
The sensors are not equally responsive to a particular gas, so you can replace one sensor the other is impractical. So, the most dangerous gas that can affect the person in everyday life, it is undoubtedly a propane (СЗН4). His explosive concentration in air is 2.1 to 9.5%. For registration of propane, natural gas and butane suitable for gas sensors TGS2610, Figaro TGS813 firms. The last type is more modern and has low voltage.