PuMaH - a temperature control and resistance read-out system for microstructured gas sensors based on PWM signals

Temperature cycling of semiconductor gas sensors is a very powerful tool for developing gas detection systems with high selectivity and stability. Microstructured gas sensors - due to their low thermal mass - have very low thermal time constants in the range of 10 ms. Based on these sensors, the development of fast and highly selective gas detection systems is possible using temperature cycles with application-specific temperature levels and an overall duration of only a few seconds. For efficient evaluation of such systems, especially in industrial applications, we have developed a flexible and low-cost hardware platform which provides accurate temperature control for arbitrary temperature profiles and fast, high resolution data acquisition either in stand-alone operation or connected to a PC. A modern MCU provides 16 bit PWM outputs which are used both for temperature control and resistance read-out. A key feature of this platform is its large effective measurement range of 26 bit resulting from a combination of 16 bit PWM with a 10 bit ADC. Based on this hardware platform, various application-specific gas detection systems either for research or industrial purposes can be realized