ABSTRACT
With the improvement of life quality nowadays, the concentration of carbon dioxide in the air has become close increasingly. Modern concentration detection system of carbon dioxide usually use the infrared sensor to direct and transform as a current or voltage signal which can be easily transformed, and then processed and real-time display by the follow-up circuit.
The paper devised a digital detector for the concentration of carbon dioxide. The sensor TGS4161 outputted the voltage signal which responsed to the concentration of carbon dioxide in the air. The signal was magnified by LM324 and converted by AD converter and then inputted into single chip microcomputer (SCM) and displayed on LED synchronously. This kind of barometer was portable, easily operated and absolutely accorded with the design requirement．
The paper was divided into six chapters. The first chapter introduction gave a brief review of the subject's background and the development and the design of the key issues. Chapter II designed the major tasks and characteristics of the subject. The following two chapters made a more systematic overview on the subject used by the electronics, microcontroller software and hardware. Chapter V was the conclusions.
