A Hand-held Electronic Nose Based On μPSD3234A Microcontroller Unit

An electronic nose (E-Nose) is an instrument, which comprises an array of electronic chemical sensors with partial specificity and an appropriate pattern recognition system, having the capablility of recognizing simple or complex odors. The E-Nose is a new type of analytical instrument for gas determination which mimics the human olfactory system, it having been attracted extensive attention since 1990. With the improvement in the sensor technology and artificial intelligence, The E-Nose has been greatly developed in its function and application. The E-Nose has shown great application potentials in many other fields, such as food industry, aviation and spaceflight, air detection, automobile, indoor security, diagnose of clinic, and so on. However most electronic noses are very expensive and big in volume, which baffled its application. It has been demonstrated that the development of electronic nose would aim at its intelligence, miniature, integration and lower price.Based on its working principle and structure, an hand-held E-Nose system was designed and prepared usingμPSD3234A Microcontroller Unit (MCU), which has been used successfully to classify and recognize gas by training after selecting gas sensor array.The hand-held E-Nose system is an MCU application system, utilizing all of interior resource and lots of exterior interface techniques of the MCU. The signal condition circuit, the periphery circuit of MCU, the power circuit, RS-232 and all of hardware configuration were designed.The E-Nose software system adopted modularization, which comprises main program and subprogram. While the subprogram include initialization subprogram and function subprogram, which is the basic of software system. The E-Nose provides a friendly interface, so that users can control the system easily.There are four parts in this thesis. In the first part, the development history and application of electronic nose was introduced, and then the principle and structure were summarizes, pointing out the development direction before the purpose and importance of our research have been presented. In the second part, an hand-held electronic nose system was designed and prepared usingμPSD3234A MCU which based on the working principle and structure, the principle and function of each parts were described. In the third part, we designed the E-Nose software system and expatiated the function which each parts achieve. In the fourth part, the electronic nose acquired data of which experimented to the VOCs gas, and then transmited the data to computer, the sample which had been trained in PC was programmed into MCU, finally the electronic nose could recognize four kinds of VOCs gas.