Characterisation of Humidity Dependence of a Metal Oxide Semiconductor (MOS) Sensor Array using Partial Least Squares (PLS)
Metal oxide semiconductor (MOS) sensors are a class of chemical sensor that have potential for being a practical core sensor module for an electronic nose system in various environmental monitoring applications. However, the responses of these sensors may be affected by changes in temperature or humidity and this must be taken into consideration when developing calibration models. This paper characterises the temperature and humidity dependence of a sensor array which consists of 12 MOS sensors. The results were used to develop calibration models using partial least squares. Effects of humidity and temperature on the response of the sensor array and predictive ability of partial least squares are discussed. It is shown that partial least squares can provide proper calibration models to compensate the effects caused by changes in temperature or humidity. However, the results also demonstrate difficulties in quantifying sensor responses to artificial piggery odour over different environmental conditions and also highlight the need to use a designed experiment for robust calibration results.