Smell identification using a thick-film hybrid gas sensor

An analytical method and experimental results of identifying and quantifying smells using an electronic system composed of an integrated sensor and a microcomputer are described. The integrated sensor with six different elements on an alumina substrate was fabricated by using thick-film techniques. The elements are kept at around 400°C by a Pt heater mounted on the sensor back. Since each element was made from different semiconductor oxides, they possess different sensitivities to material odors and the integrated sensor can develop specific patterns corresponding to each odor as a histogram of conductance ratios for each element. The microcomputer identifies the scent on the basis of similarities calculated by comparing standard patterns stored in the memory and a sample pattern developed by the integrated sensor. The scent is then quantified by using the sensor element with the highest sensitivity to the smell identified. The experimental results show that smells can be successfully identified and quantified with the electronic System.