Hand Held Electronic Nose for VOC Detection

In this work we present a novel hand held electronic nose. This electronic nose is a lightweight instrument with wireless communications capable of stand alone operation. It has been designed to accept and work with several types of resistive microchemical sensors. The electronic nose can be operated stand alone or controlled externally by a personal computer. The external measurement and control program has been developed in Labview. Although this device has been developed for indoor applications it is versatile enough to be used as a general purpose low cost electronic nose. A low volume microsensor chamber has been designed to accept several sensor packages. The device has been tested in laboratory with volatile organic compounds (VOCs) such as acetic acid, acetone, ethanol, propanol, hexanal, ethyl acetate, acetaldehyde, butanediol, toluene and xylenes. The external program that controls the measurements performs real time data processing through linear pattern recognition techniques such as principal component analysis (PCA). Non linear pattern recognition techniques such as neural networks have been developed in Matlab for identification and classification purposes. Comparison between these methods is accomplished.