Fabrication Of Gas Sensor Based On Micro-hotplate And Its Detection System

With the development of human society, more and more attention has been paid to environmental issues. The variety of toxic and hazardous, flammable and explosive gases in the air pose a serious threat to human life and property safety. Although we have developed the testing equipment, based on mass spectrometry and spectroscopy, the instrument is bulky and expensive, which is not conducive to popularization. The Micro-hotplate gas sensors with the advantages of small size, low power consumption and easy integration, have become the hot spots of gas detection. In this paper the design of gas sensor based on the micro-hotplate and its detection system were carried out to develop small size, low cost, easy to carry gas analysis detector.Based on the analysis of the micro-hotplate structure and its heating characteristic, the gas sensors was prepared by positioning coating by droplet guide on100μ×100μm micro area. The array type of dynamic detection system had been designed according to the characteristic of the micro-hotplate gas sensor parameters. Through the acquisition of each gas sensor’s voltage signal, the sensitivity of gas sensors and its related parameters were finally got. The hardware circuit design, selection of the set A/D conversion and control of a MSP430F149micro-controller, concerts the collected analog signal to a digital signal and then sent to the serial port after a SCM processing, the serial communication is used for showing the voltage curves on the interface of PC, then data communication between the lower machine with the host computer is achieved. The software design integration into the modular and general thinking, the main program only on the function of each function call, each performance function is versatile and easy to transplant.Analysis and test results showed that the gas-sensing material droplets guide position coating method had better solved the problem of material coating on the micro area, the degree of adhesion between the micro-hotplate and gas-sensing material was better. By improving the preparation process and doping with different impurities, the sensitivity of gas sensors had been improved.