Design Of Odor Electronic Nose System

With the development of economy, the industrialization level and people’s living standard iscontinuous increasing, along with the evolution of the concentration of industry and populationdensity, who led to the emissions of malodorous gases increase very obviously. At present, odorpollution has become one of the main hazard of air pollution, which not only pollutes theenvironment for human survival, but also do harm to human health. Therefore, in order tomonitor the malodorous gases in real-time and guarantee the quality of people’s life, a simple andaccurate method of measuring need to be studied. So the stench of electronic nose systememerges as the times require.In the field of odor pollution control, each country has its own standards. Our countrystarted relatively late in the research field of odor gas electronic nose system, so there is a gapbetween our country and the countries which started earlier. Address this situation, based on theintensive study of the human olfactory system and the electronic nose system design principles,we design and develop a electronic nose system for foul odor detection. The whole systemincludes hardware and software two aspects.The hardware part of odor electronic nose which is designed based on single-chipmicrocomputer system is mainly composed of three parts, which are the sensor array, the systemcontrol circuit and the system gas way structure. Among them, choosing the electrochemicalsensors specially measure gas in the part of sensor array, then the overall performance of thesystem is improved and the data processing process is simplified; the part of system controlcircuit makes full use of the rich interface resources of the single-chip microcomputer ofC8051F020, which ensuring the system’s function expansion. Adopting a system of new gaspassage structure in this paper ensures the continuity and repeatability during the measurementprocess and the acquisition process and reduces the influence of external factors and improvesthe precision of measurement.The software part is consisted of the lower machine software and the PC software. Thelower machine software is written in the assembly language which can display sampled data ofeach channel individually, control system to work and connect to the PC computer to achieve sampling and sending data either. The PC software is written in LabVIEW which can realize thatthe PC computer can control the work state on the lower machine, and manage data sampled bythe lower machine to display and store with convenient and simple interface by the user.Electronic nose system is used to make signal gas experiments for different concentrationsgas, including NH3, H2S and ethyl acetate, at the same time analyzing each sensor’s responseprocess in different malodorous gases, which providing the theory reference for further dataprocessing and pattern recognition.