Environmental data card utilizing SAW gas sensors and PCMCIA interface

Nowadays the monitoring of environmental data like air pollution concentrations demands low-priced, mobile, and easily adaptable gas sensor systems. To meet such requirements we are developing an environmental data card for gas detection based on a PCMCIA card carrying up to four SAW chemical gas sensors in a small air chamber. The utilization of this interface card with its geometry internationally standardized offers widely applicable solutions for both mobile gas monitoring using a laptop and autonomous operation with a separate power supply e.g. at rather exposed places. The concept and the set-up of the system were discussed earlier. This paper presents results of the optimization of SAW sensor layer properties and of film conductivity probes on the sensor chips exposed to NO₂ gas. Furthermore the updated set-up of the system, the data acquisition and the rather complicated managing of temperature, gas flow and signal processing are discussed. New results of the interworking of the multisensor card components are reported.