| A wireless sensor system for measuring ambient carbon monoxide (CO) concentrations, temperature and relative humidity was developed at the University of Cincinnati's Department of Civil and Environmental Engineering and the Center for Distributed and Mobile Computing, the Computer Science Department. The system was designed to utilize an electrochemical sensor, on-board temperature and humidity sensors and a wireless communication system to transmit data to a central processor. An exposure chamber and a validation system were constructed to verify the relationship of the gas sensor response to CO concentrations as a function of relative humidity (RH) and temperature. The responses from the CO wireless sensor system were compared with the data observed by a U.S.EPA reference method non-dispersive infrared (NDIR) analyzer, and National Institutes of Standards and Technology (NIST) traceable thermo-hygrometer. Exposure chamber environmental conditions were operated in the range from 8--35°C, 30--70% relative humidity (%RH) and a CO concentration range of 0--10 ppm. The experimental results provided a good linear correlation between the measured CO signal from the wireless sensor and the concentration as measured by the NDIR analyzer, with a correlation coefficient (R 2) ≥ 0.99 in the temperature and RH ranges. |
