Publication Date


Document Type


First Advisor

Ganesan, Sengoda G.||Hamm, Erwin C.||Newell, Darrell E.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Industry and Technology


Gases; Asphyxiating and poisonous; Real-time data processing; Gas-detectors


This thesis describes the design and implementation of a toxic gas monitoring system capable of detecting, analyzing, and displaying ambient toxicity information in real time. All the necessary control and data analysis functions are provided by a dedicated microcomputer, configured as part of the monitoring system. The first portion of this report will bring forth some of the reasons why such monitoring instruments are necessary. Secondly, the technical aspects of existing colorimetric detectors will be briefly introduced, specifically focusing on a particular instrument’s design flaws and needed improvements. This existing instrument was then used as a foundation in the development of a completely modernized monitoring system, as explained in this paper. Toxic gas concentration levels are detected by an opto- electric transducer with the aid of a chemically treated, commercially available paper tape. As a form of response, its surface color changes as a function of present levels of toxicity. This method of detection warrants the need of an error correction circuit, developed to compensate for paper tape non-homogeneity and initial non-uniform absorption of color reagents. She constructed monitoring system was designed to be used as a toxic gas environmental dosimeter by technical as well as non-technical personnel. To maximize flexibility and ease of operation, an operating system software capable of supporting user interactions and control functions was formulated.


Includes bibliographical references.||Includes illustrations.


viii, 108 pages




Northern Illinois University

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