Research Of Portable Methane Gas Detection Device

In recent years,accidents of coal mine explosion and natural gas leakage occur frequently,which bring serious threat to people's life safety.Therefore,the research work of portable gas sensor for on-site monitoring becomes very important.A NB-Iot portable methane sensor is designed based on the working principle of non-spectral infrared method.In this paper,several traditional gas sensor methods are firstly analyzed and compared to determine the theoretical basis of methane gas detection based on spectroscopicity.Then on the basis of lamberbier's law,the harmonic detection method is put forward,and the theoretical formula which can calculate the gas concentration is deduced.By studying the molecular characteristics of methane,the absorption wavelength of methane was determined,and the suitable pyroelectric detector and infrared light source were selected.In terms of hardware,STM32 single chip microcomputer is selected as the controller,and the minimum system,infrared light source modulation circuit,power circuit,small signal amplifier circuit and communication circuit are designed.The collected gas voltage signal is amplified through the amplifier circuit and transmitted to the single-chip microcomputer.The collected data is processed and transmitted to the host computer and the display interface through the algorithm.Through LabVIEW to the single-chip microcomputer software programming and the development of the upper computer.Finally,the sensor is calibrated,and the measured voltage and gas concentration are fitted to get the relationship between voltage and concentration.The relationship between temperature and concentration is deduced through experiments,and temperature compensation is carried out.