SNIFFER: An electronic nose

In this paper we present SNIFFER, an electronic nose consisting of an array of conducting polymer sensors with partially overlapping sensitivities, and a pattern recognition system based on a new linguistic fuzzy classification method. The method describes the shape of the sensor responses in terms of linguistic expressions, which are derived from a fuzzy partition of the area occupied by each response. The sensors are exposed to odorants and the percentage change in resistance is used for classification purposes. Results of the application of SNIFFER to the recognition of different types of waste water produced both by the industrial activities of leather tanneries and by municipal sewers are presented.