City Gas Leak Alarming with Pattern Recognition Algorithm Using a Thick Film Integrated Sensor and a Microprocessor

This paper describes a geometrical method of discriminating and quantifying gases using an electronic system composed of an integrated sensor and a microprocessor. The integrated sensor with three different elements on an alumina substrate was fabricated by using thick film techniques. The elements are kept at around 400•Ž by a Pt heater mounted on the back of the substrate. Since these elements were made from different semiconductor oxides, they possess different sensitivities to methane as the principal component of the city gas, carbon monoxide generated by imperfect combustion, and ethanol and hydro-