Odor Recorder Based on an Array of QCM Sensors Using Frequency Shifts and Resistance Changes of Multiple Harmonics

Our odor recorder is able to quantify an odor mixture as the concentration recipe of several odor components. It is based on an array of four quartz crystal microbalance (QCM) odor sensors coated with sensing films. With a system measuring both the resonant frequency shifts and resistance changes of multiple harmonics of QCMs, the selectivity of the sensor array has been improved. In this study, an improved control algorithm to set initial recipe was also proposed. The results of odor ternary mixture quantification experiment indicate that the proposed method with the expanded responses reduced the root mean squares error and convergence time to almost one third. To the best of our knowledge, this is the first paper about odor quantification using both frequency shifts and resistance changes of multiple harmonics of QCMs.