Measurement of Bad-Smell Distribution Using Sensing Network Composed of Nodes with Gas Detector Tubes and CCD Image Sensors

Abstract

We have developed multi-point bad-smell sensing system for monitoring living environment. Although there are a variety of gas sensors, it is difficult to detect ppb-order gas without interference. Our previous system was able to detect methyl mercaptan, hydrogen sulfide, propion aldehyde and toluene with the concentrations down to a few tens of ppb by using a gas detector tube combined with a CCD image sensor. A gas detector tube with color change caused by the chemical reaction between the analyte and the reagent system was implemented into our low cost wireless portable measurement system. This portable system called a sensor node consists of a gas detector tube, one-dimensional CCD image sensor, LVDS interface, microcomputer, and wireless LAN module. We report experiment on gas-distribution measurement under actual environments such as paint factories. It was found that the gas distibution around paint factories could be measured using this sensor network. Moreover, the dynamical change of gas distribution was clearly observed.