Highly sensitive ammonia sensor

Electroconductive polymer based gas sensors have been investigated focusing on the resistance changes when exposing them to ammonia atmosphere. Firstly, the resistance increase of these devices in air after manufacturing them, secondly the changes in resistance after exposing them to different concentrations of ammonia was examined. These phenomena and also the possibilities of enhancing the operating speed of the sensor by curve prediction are described and examined here. A possible data processing system is outlined for enhancing the accuracy of the measurements. The resistivity changes in time (drift) and memory effect of the polymer is taken into account. The main topic of this paper is what kind of problems we must face during signal processing of the responses given by this type of devices when designing a fast and accurate concentration measuring system, the other is how the speed can be enhanced.