Researches on a practical system for concentration detection of human exhaled CO 2 gas

In clinics, especially in the emergency department, carbon dioxide (CO2) is considered as the sixth vital sign in evaluating a patient's medical status. However, its wide applications in developing countries are dissatisfactory due to their high cost compared to their economic growth. In order to develop a practical system for concentration detection of human exhaled CO2 gas for our own, we studied the detection principle based upon the non-dispersive infrared (NDIR) measuring technique and related Lambert-Beer's equation carefully, gave out our functional circuit design of the system, and provided the corresponding graphical user interface (GUI) for CO2 detection. Finally, the experiment shows that it may be a practical system, and will give benefits for the development of our medical care in the future.