Signal processing for improving gas sensor response time

Abstract

In this paper, we describe a system for reducing the response time of gas sensor arrays. The system uses analog signal processing techniques to analyze the transient response of sensory inputs sufficiently to discriminate among chemicals of interest before steady state is reached. The signal processing thresholds the sensory inputs at periodic intervals during the transient response, thereby producing a binary wavefront that is stored and retained for discrimination tasks. Experimental results described in this paper effectively reduce the response time of an array of discrete tin-oxide gas sensors from 10 to 2 s; experimental data are consistent across a range of concentrations for a variety of reducing gases. We expect that equivalent improvements in response time will also be possible for integrated microsensor systems using the same techniques described in this work.