10-04-2017, 08:53 PM
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THE ELECTRONIC NOSE AND THE BIOLOGICAL NOSE
or
smell scencer
abstract
A few smell-sensing instruments had been proposed in narrow applications earlier in the 1960 s. Moncrief developed one of the first smell detection instruments in 1961 for agricultural application, where he used a single coated thermistor as the smell sensor. In 1964, Wilkens and Hartmen developed a smell detector where an array of smell detectors was used [8].It was in late 1980 s that the first intelligent electronic smelling system came into being. Researchers in the University of Warwick in Coventry, England, developed sensor arrays for odour detection [5]. Pattern recognition techniques were used by Gardner to discriminate the output of electronic smell sensors. Hartfield described an integrated circuit based device that performs data acquisition from a miniature array of 32 conducting polymer gas sensors. David and Gardner designed a circuit capable of measuring signals from arrays of resistive and piezoelectric sensor types in the same board [8].
Electronic noses were originally used for quality control applications in the food, beverage and cosmetics industries. Current applications include detection of hazardous chemicals and explosives, detection of odours specific to diseases for medical diagnosis, and detection of pollutants and gas leaks for environmental protection. The Warwick pioneers envisioned an electronic equivalent of the mammalian olfactory system and so even though it doesn t resemble its biological counterpart the least bit, the label electronic nose or E nose has been widely adopted. [5].