A portative gas recognition system based on metal oxide gas sensor array

Abstract

A portative electronic nose is conceived especially to detect several pollutant gases and estimate the concentration of these atmospheric components. The interest of our multisensor system is its entire autonomy, low weight and very small size for embedded applications, and its flexibility. Six commercial gas sensors (Figaro) with interesting cross sensitivity and almost low power consumption are used; a micro-controller equipped with a compact flash memory assures data acquisition, analyzing procedures, and data transfer or storage. The prototype is first validated in laboratory by generating atmospheres containing various concentrations of three pollutant gases (H 2 S, NO 2 and SO 2 ) in the range of industrial areas with variable humidity rate. An excellent group separation for the gas natures is obtained by using a multidimensional data analysis algorithm which also allows concentration determination of the gases.

A Readout System for High Speed Interface of Wide Range Chemiresistive Sensor Array

“…Let us denote V (nogas) as ADC voltage in (1) without target gas exposure and V (gas) indicates ADC voltage as per (1) in condition where sensor is exposed to gas in conventional R-V method, where R ref is fixed to R mid . The term of V = V (nogas) − V (gas) stipulates the ADC voltage change due to target gas variation and is derived in (7) using ( 5) and (6).…”

“…Chemiresistive sensors have been widely investigated and used for toxic/harmful gas detection [1]- [3], environmental monitoring [4]- [6], food inspection [7]- [10] and various other applications [11] because of their merits such as simple sensing mechanism, cost effectiveness, and excellent sensitivity. The chemiresistor or chemiresistive sensor is a class of chemical sensor that changes its electrical resistance in response to chemical interaction between the sensing material and the target analyte.…”

A Remotely Controlled Calibrator for Chemical Pollutant Measuring-Units

“…The most interesting features of such devices are their low cost and small size, while the main drawback is a poor selectivity, since their output is affected by different kinds of gases. Cheap and compact measuring units can be therefore arranged, which usually employ sensors that sense different target gases, thus allowing the different outputs to be suitably processed in order to improve the gas selectivity [4], [5]. Another interesting application of such sensor-based measuring units is the monitoring of urban areas, which is performed by placing the units on vehicles running on the streets.…”