Design Of Portable Multi-gas Concentration Detector

At present, human life and production activities and the use of energy is given priority to with fossil fuels.Fossil energy in the process of production and consumption will produce a large amount of gas, the gas composition in human life or work environment more complex, with the accumulation of toxic or harmful gases, it is easy to cause potential safety hazard.By zhengzhou a gas testing company, in view of the environment in a variety of gas concentration detection, this topic can design a while detecting methane, oxygen, hydrogen sulfide and carbon monoxide gas concentration parameters of portable gas detection instruments, can real-time display the gas density, and can send out alarm signal according to the pre-set alarm threshold.According to the design of instruments and gas detection method of the pros and cons,this topic selection electric chemical formula and catalytic combustion type gas sensor combination plan.Research and design of the four types of gas sensor output signal of the signal conditioning circuit, based on the ARM Cortex-M3 kernel STM32 micro controller as the master control chip, chip peripherals ADC as analog signal acquisition of AD converter, designed the three buttons and LCD display as humancomputer interaction module, LED, buzzer and vibration motor as alarm circuit module, completed by AD6.9 system schematic diagram editor and PCB drawing.In the aspect of software design, this topic is based on MDK integrated development environment and the standard peripherals library STM32 completion system application programming, implement the system in the data acquisition and processing, human-computer interaction, alarm, the function of the calibration procedure, etc.The idea of modular programming, easy debugging and modification of late.In the design of data acquisition and processing software and digital filtering algorithm, improves the software anti-interference ability and stability.Under existing experimental conditions, do calibration and testing of this system, the test results show that the system is in the range, error, alarm, etc. Various performance indexes can meet the design requirements.At the end of the paper points out the deficiency of the system at present, and pointed out the further perfect the system of research direction.