Design Of Portable Methane Gas Detection With USB Interface

With the rapid development of the domestic coal industry and vigorouspipeline construction work, the portable gas detector has been paid moreattention. Therefore, development of a safe and reliable gas detector is thefirst and foremost task. However, the vast majority of coal mines andpipelines accidents are caused by gas explosion, such safety hazards become aserious threat to the people’s production and life. Therefore, the design ofreliable and efficient gas detection systems is essential.By reading a lot of gas detection technologies domestic and foreigndocuments, understanding the principles of gas detection technology,referencing the trend of gas detection technology in recent years, the gasdetection system made a thorough research. In this paper, TI’s MSP430F5510MCU and the City’s IRceL sensor combined, to its peripheral circuits make adetailed analysis and functional optimization, and based on the analysis ofinfrared detection technology principle and concentration calculationalgorithm, further complete the design of gas detector with the USB interface.The control chip sends a square wave of2Hz as a drive signal of the sensor,and the sensor converts the methane concentration in the current environmentto electrical signals feeding to the signal receiving circuit, then through thesecond-order low-pass signal processing circuit and the second-order high-pass filter amplified, getting the sinusoidal signal having a specificrelationship with the concentration of methane. After the controller chipreceives the reference channel and measuring channel two sinusoidal outputsimultaneously, feeding them into the control system, after calculation,processing, compensation obtained the concentration of methane gas.Software design includes signal analysis and processing, and informationstorage. By debugging and experimental analysis, the system of performanceindicators basically conforms to the national standard coal mine methane by non-dispersive infrared sensor indicator issued by the State Administration of WorkSafety.The system has wide operating temperature range, its response time canalso meet the requirements. The coal mine methane sensor not only has highdetection accuracy and reliability, but also has liquid-crystal display which caneasy to read. The collected data can be sent to a computer for data analysisthrough the USB interface, which has development and application value.