Design Of Electronic Nose System Used For Perfume Quality Evaluation

With the improvement of the people’s living standards, perfume, asa new fashion, has become an integral part of our daily life and gainedmore and more attention. However, there are many shoddy and inferiorproducts on the market, and it is hard to guarantee their safety andquality. Therefore, how to detect the perfume effectively becomes moreimportant.Recently, an electronic nose (E-nose) has attracted much attentiondue to its potential applications in food quality control, medicaldiagnosis, environmental monitoring and pollution measurement. Theappearance of E-nose provides a new technology and method for the perfumequality evaluation. The traditional detecting technologies have somedisadvantages. Judging by the sense of highly qualified professionalpeople is more or less subjective. Gas chromatography (GC) is costly andcomplex. But E-nose based on gas sensors is cheap, portable and efficient.So in this work, an E-nose has been designed in order to evaluate thequality of perfume.Based on its working principle and structure, an E-nose system wasdesigned from two parts including hardware and software.The hardware design of this E-nose system consists of three main partsincluding sensor module, control circuits and sampling chamber. The coreof the hardware used for data acquisition and transmission isdsPIC30F6014A which contains68GPIO pins and has high speed, highstability and reasonable price. The12-bit Analog-to-Digital Convertermodule on-chip permits a maximum of200ksps sampling rate that can meetthe sampling requirement of the system. The sensor module is composed of six commercially available metal oxide semiconductor sensors and onetemperature&humidity sensor, which is used to monitor the real-timetemperature and relative humidity of the operational environment. Thesampling chamber is sealed by glasses with a fan, and a minipump is usedto clear the chamber.The software development includes the software design of signalacquisition system, the man-machine interface of upper computer and thepattern recognition algorithm. The software design of signal acquisitionsystem means to drive MCU, ADC, UART and display screen. Theman-machine interface is friendly and concise, developed by MFC of VisualC++. It can communicate with MCU, display and save the sample data andthe recognition result. The pattern recognition algorithm adopted in thisE-nose system is Support Vector Machine, which improves thegeneralization performance of small sample. It was developed by mixedprogramming of VC and MATLAB based on COM component.Four kinds of perfume had been learned and classified to test theoverall performance of the E-nose system. Through the recognition ofvarious perfumes, the accuracy and feasibility of this E-nose system wereconfirmed.