The Research On Noxious Gas Detecting System Based On Mid-Infrared LED

The plague of air pollution throughout the world is deteriorating. The economicloss and decline of urban residents' health condition incurred by worsening air qualityare grabbing attention from more and more people and governments. The high percentof hazardous content released to the air is the major factor. Hence, the development ofan effective instrument and corresponding set of method to detect the proportion ofnoxious air is urgent and indispensable.Traditional nondispersive infrared air analyzing device has the weak point of highmaking cost and low flexibility. We proposed and discussed in this paper a newnoxious air detecting system based on MIR-LED. We can use the new system torealize an online real time detection method. Through that method we can boost thedetection efficiency, lower the making cost and ameliorate air quality in urban areaand in our homes.This paper begins with the entire device structure. Then we explain our designingthought for every modules of the system. Much emphasis is put on the reason why weutilize MIR-LED as the infrared light source. Next we designed the circuit diagram ofhardware part and finally implement the software programming. The entire systemcan be divided into three modules in terms of functionality: â—‹1 mono infraredemission system â—‹2 data collecting system â—‹3 Control system. Mono infraredemission system consists of MIR-LED array and corresponding driver circuit. Datacollecting system consists of photoelectricity detector and its bias set circuit, signalamplifier circuit and A/D converter circuit. Control system consists of logical controlcircuit and keyboard, display circuit and so on.We conclude this paper with experiments and the performance result. Through thediscussion and analysis of the experiment result, we come to the conclusion that thenew instrument reaches our designing intention. Next we will extend and better thefunctionality of our instrument. Our newly improved system will work well and havea broad range of application in practical use.