Portable electronic nose system with gas sensor array and artificial neural network

A portable electronic nose system has been fabricated and characterized using an oxide semiconductor gas sensor array and artificial neural network. The sensor array consists of such thick-film oxide semiconductor sensing materials as Pd-doped WO 3, Pt-doped SnO 2, TiO 2–Sb 2O 5–Pd-doped SnO 2, TiO 2–Sb 2O 5–Pd-doped SnO 2+Pd-coated layer, Al 2O 3-doped ZnO and PdCl 2-doped SnO 2. The portable electronic nose system consists of an Intel 80c196kc as CPU, an EEPROM and an LCD for displaying gas concentrations, etc. As an application, the system has been used to identify 26 CO/HC car exhausting gases and the identification has been successfully demonstrated.