Testing of Carbon Monoxide and Carbon Dioxide Sensors with Simple Apparatus in an Engineering Education Laboratory

摘要

As part of a summer internship in materials engineering, the characteristics of carbon monoxide (CO) and carbon dioxide (CO_2) sensors were investigated. These gases were chosen for this work because of the materials used in the sensors and their importance in environmental testing and monitoring applications, both indoor and outdoor. The work was performed in an electrical engineering laboratory facility which lacked sophisticated chambers for testing gas sensors. Homemade chambers were constructed from readily available components. Commercially available probes for the measurement of CO and CO_2 were purchased and used as the reference devices for the testing and calibration of the sensors under test. Gases for testing each sensor were obtained from common sources. Conditioning electronics for each sensor were constructed per the manufacturer's datasheets and applications notes. Data acquisition software was written using LabVIEW to create virtual instruments for each sensor. This paper presents the motivation for investigating CO and CO_2 sensor performance and applications. The sensor test chamber design considerations and the actual chamber design are also presented and discussed. The problems and safety concerns associated with using CO and CO_2 are provided together with the safe handling methods employed during this investigation. Methods for obtaining the required test gases are presented. The sensor signal conditioning hardware is also provided. Experimental results and future applications of this work are presented and discussed. This paper presents materials and methods that can be implemented in an engineering education laboratory environment with minimal investment yet still produce satisfactory results.