A simple interface circuit for micromachined gas sensors

This paper describes a microcontroller-based interface circuit for chemoresistive metal-oxide gas sensor dedicated to environmental pollution detection. The circuit controls the sensor operating temperature, measures the sensing layer resistance, offering also a user-friendly interface. The main system features are: wide dynamic measurement range, self-calibration capability, built-in RS-232 interface and two different methodologies of data acquisition, namely constant and pulsed temperature modes.