| The pollution becomes more and more serious because of the industrial development, especially gas pollution which is seriously hazard to the health of humans. Meanwhile, "Indoor air pollution" caused by interior decoration results in diseases, which has attracted highly attention in many countries. Air pollution is harm to people's health, and it can easily cause respiratory disease, such as high concentrations of pollution can cause acute poisoning and even death, chronic bronchitis bronchus asthma, emphysema and lung disease can be cause in low concentration pollution for long period, some pollutants also damage lung's transaired function and oxygen function. Therefore, a regular, fast and effective toxic or harmful gases detection is extremely important.Based on the comprehensive analysis of domestic and international gas sensor detection techniques, according to the principle of porphyrin array sensing fingerprint characteristic, and on account of embedded ARM - Linux technology, a kind of portable harmful gas detection instrument has been put forward, and it can realize the function of rapid, accurate detection of trace.A closed gas detection system is reported in this paper, toxic or harmful gases is pumped into the reaction gas chamber, the image information of the reaction between gas and porphyrins sensor array chip is collected by the camera through the touch interface, the information of the measured poison gas is got and displayed on the touch interface and selectivity stored after the processing by S3C2440. In this paper, the mainly work contains the design of the software and hardware parts about the detection system, and the following several aspects have been completed:1. According to the actual demands of gas detection, based on the modular design ideas, and adopted the way of separate mode plan, the hardware circuit of the detector is designed. The embedded control system adopted ARM9 (S3C2440A) as the core, and it included image acquisition module, LCD touch display module, storage module, serial communication module and power module, etc.; the micro control system adopted PIC16F877 as MCU core, and which included gas sampling module, condition monitoring module, illumination module, communication module, etc. The system accomplished the poison gas detection through the collaboration between ARM9 and MCU system. 2. In this paper, the building of the development platform development environment , the writing of boot programming and kernel cutting of the embedded ARM– Linux have been completed, and the driver and part of the application software was designed; the writing and testing of the drivers program for MCU was also completed in the development environment of MPLAB 8.0.3. According to the technical indexes and external properties of hardware device of the gas detector, and using AUTOCAD design the model figure of instrument assembly, the equipment assembling and commissioning was completed.4. Some typical gases were tested by the detection device. From the operation of the instrument, the experiment control condition were understood, the operating experience was accumulated, and lastly the test results verified the effectiveness of the instrument.5. Some gas, such as heptanal, ammonia, benzene, p-xylene, chlorine and sulfur dioxide were tested by the gas detection equipment. These analyzed data proved the effective recognition of the testing results.Finally, the research work is summarized, and the further perfection of the gas detection equipment is proposed. |
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