Resolving Fast Gas Transients with Metal Oxide Sensors.

Damien Drix,Michael Schmuker

doi:10.1021/acssensors.0c02006

Abstract

Electronic olfaction can help detect and localize harmful gases and pollutants, but the turbulence of the natural environment presents a particular challenge: odor encounters are intermittent, and an effective electronic nose must therefore be able to resolve short odor pulses. The slow responses of the widely used metal oxide (MOX) gas sensors complicate the task. Here, we combine high-resolution data acquisition with a processing method based on Kalman filtering and absolute-deadband sampling to extract fast onset events. We find that our system can resolve the onset time of odor encounters with enough precision for source direction estimation with a pair of MOX sensors in a stereo-osmic configuration.

Highlights

Electronic olfaction can help detect and localize harmful gases and pollutants, but the turbulence of the natural environment presents a particular challenge: odor encounters are intermittent, and an effective electronic nose must be able to resolve short odor pulses
We developed a signal processing method based on a Kalman filter and absolute deadband sampling to isolate successive bouts and encode their onset time
Our gas sensor boards consist of four metal oxide (MOX) sensors and a high-resolution analog-todigital converter (ADC)

Summary

Introduction

Electronic olfaction can help detect and localize harmful gases and pollutants, but the turbulence of the natural environment presents a particular challenge: odor encounters are intermittent, and an effective electronic nose must be able to resolve short odor pulses. In natural environments, odors are dispersed by turbulent plumes and encounters are intermittent.[1] The temporal statistics of these odor pulses (hereafter called bouts) contain information about source location.[2] An effective electronic nose needs to resolve both short pulses and pulses in rapid succession. Metal oxide (MOX) gas sensors are widely used, but have impulse response durations on the order of tens to hundreds of seconds,[3] and are often thought to be of limited utility in turbulent environments. We demonstrate the system’s ability to resolve onset times and repeated bouts in a stereo-enose setup that infers the direction of a puff of odorant from stereo delays

Methods

Results

Discussion

Conclusion