Recognition of complex odors with a single generic tin oxide gas sensor

We report, for the first time, discriminating among complex odors using a single generic tin oxide gas sensor. The sensor heater is biased with high magnitude voltage impulses of predetermined thermal impacts adjusted to produce step-like pallet temperature rises of different magnitudes. The sensor pallet is exposed to aromas collected from various herbs and spices at different concentrations. The test period is 4 s only, during which the sensor pallet undergoes four step-like temperature jumps. The discriminative features extracted from the normalized response patterns recorded for six different herbs and spices, each at various concentrations in air, afford their clear segregation in the feature space and recognition. The capacity of the device to discriminate among complex odors and single-component small molecule gases in a unified feature space is demonstrated. The odor discrimination power of the system is almost aging drift-proof; response patterns recorded for a specified odor at independent experiments carried out during the nominal lifetime (six months) of the sensor join the correct cluster in the feature space.