The reaction mechanism of the MOS sensor TGS822 sensitive to butanone was introduced.The feasibility of the sensor used in the air fresh test of range hood was analyzed.The experiment system of analog kitchen was then designed in the laboratory,to conduct the response test of the sensor in the process of concentration rising and falling,then the standard sensitivity curve of the sensor sensitive to butanone was drawn.For the inconsistency between the individual sensors,a ratio correction method was proposed depend on the linear relation between different points on the curve.Then the dilution model of the gas concentration in the cabinet was established,and the hysteresis characteristic of the sensor was analyzed and simulated on the basis of this model.The results showed that this type of sensor had a good response sensitive to butanone under the concentration of 200×10-6.The detection limit of the system could reach about 1×10-6.And the system response had steep time characteristics,so it could effectively meet the requirement of on-line detection in the air fresh test.

We have developed a novel colorimetric sensor based on a digital camera and white LED illumination. Colorimetric sensor arrays (CSAs) were made from a set of six chemically responsive dyes impregnated on an inert substrate plate by solution casting. Six common amine aqueous solutions, including dimethylamine, triethylamine, diisopropylamine, aniline, cyclohexylamine, and pyridine vaporized at 25 °C and six health-related trimethylamine (TMA) concentrations including 170 ppm, 51 ppm, 8 ppm, 2 ppm, 125 ppb and 50 ppb were analyzed by the sensor to test its ability for the qualitative discrimination and quantitative detection of volatile amines. We extracted the feature vectors of the CSA's response to the analytes from a fusional color space, which was obtained by conducting a joint search algorithm of sequential forward selection and sequential backward selection (SFS&SBS) based on the linear discriminant criteria (LDC) in a mixed color space composed of six common color spaces. The principle component analysis (PCA) followed by the hierarchical cluser analysis (HCA) were utilized to discriminate 12 analytes. Results showed that the colorimetric sensor grouped the six amine vapors and five TMA concentrations correctly, while TMA concentrations of 125 ppb and 50 ppb were indiscriminable from each other. The limitation of detection (LOD) of the sensor for TMA was found to be lower than 50 ppb. The CSAs were reusable for TMA concentrations below 8 ppm.

Based on TGS2620 metal oxide gas sensor,an odor compass system has been developed.The sampling system and auxiliary circuit are designed.The odor compass system is tested to locate the point odor source in 360° under the advection,and find the relation between the radio of resistance response from different sensors and the system deflection angle α.The experimental results show that the response messages for the odor sources with 30°disparity has obvious difference.And consider the radio of resistance response as the feature quantity reduces the influence from the difference between the same kinds of sensor.

This paper mainly introduces the principle,the design of hardware and software,and the entire application process of a kind of gas testing system based on microcontroller.Poison gas contained CO,H2S,CH2O can be measured by this system.The system was corrected by experimentation.The system is small,cheap and reliable.It is mainly applied in some industry scene position monitoring.