Analog VLSI circuits for odor discrimination

Traditionally, microelectronic chemical sensors have been plagued by a variety of performance problems related to drift, reproducibility, and selectivity. To address these problems, we have designed and fabricated collective analog VLSI circuitry that processes the outputs of an array of chemical sensors in a manner that facilitates robust chemical discrimination. This circuitry chooses the winner (maximum output) in an array of tin-oxide chemical sensors that operate at various temperatures. The location of the winner and its relationship with neighboring sensors has proven sufficient to discriminate among several types of alcohol and smoke. We present this approach to chemical discrimination as a fast, inexpensive alternative to more traditional methods of chemical sensing