Model based conductance measurements design for thermally modulated sensor arrays

This paper describes a model-based conductance measurement design for a metal oxide gas sensor based on tin oxide. The model accounts a conductance measurement system and a corresponding temperature control system. It is demonstrated that the chemical analysis capability with metal oxide gas sensors based on tin oxide can be considerably enhanced when the sensors are under thermo-cyclic operation mode. The sensor response is expressed by the conductance-overtime profiles. Based on preliminary studies, the sensor has shown wide range variation of resistance values. In order to interface this kind of sensor, a direct conductance measurement circuit with gain-ranging signal processing as well as temperature control system is developed for multi metal oxide gas sensor arrays. The system is modeled and analyzed in Simulink and then implemented in an embedded system.