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The Research Of Quartz Crystal Microbalance Sensor For Indoor Air Quality Detecting

Posted on:2006-12-09Degree:MasterType:Thesis
Country:ChinaCandidate:H Z LuFull Text:PDF
GTID:2168360152475790Subject:Measuring and Testing Technology and Instruments
Abstract/Summary:PDF Full Text Request
Quartz crystal microbalance gas sensor is a new-fashioned mass effect sensor. By using an AT-cut quartz crystal as an energy-exchange organ and the sensitive film on quartz crystal surface as a sense organ, it transfers the concentration signal of target gas to frequency signal, accordingly achieves detecting of gas concentration.In order to develop indoor air quality gas sensors, we lucubrate QCM gas sensors and its application in this paper, and fulfill: set up a dynamic demarcating system of array gas sensors; develop a portable frequency detecting instrument of QCM gas sensors; radicate the manufacture process of QCM sensors with experiments and produce a passel of QCM humidity sensors; build a wireless collection system of signals from QCM gas sensors.The signal detecting of QCM sensors focuses on the measuring of micro relative frequency shift. According to the character of QCM gas sensors, circuits of oscillating, transforming, differential frequency processing and A/D transferring are designed to detect the signals from sensors by transferring the micro relative frequency shift to square wave signals of which frequency varies with gas concentration. A LM331 converter is used to make signals from gas sensors convert to voltage signals collectable with A/D collectors and a detecting system applicable to QCM array gas sensors is developed combined with the existing programmable calibration system for gas sensors in labs. Another processing way is to use the microchip to deal with the QCM sensor signals, and achieves sensor signal's sampling,store, LCD display and serial communication with computers. With above two ways of frequency detecting, a passel of QCM humidity, ethanol and acetone sensors and sensors which can respond to formaldehyde gas of high concentration are developed relied on the experiments on the macromolecule film,Pt spatter film and carbon nanotubes film etc.And in the field of wireless sensors application, a wireless signal collection system of QCM sensors is built with MSP430F123 MCU and TRF6900 wireless RF transmitting/ receiving chip of Ti Company and makes a base for its application in the wireless field.
Keywords/Search Tags:quartz crystal microbalance, gas sensor, measurement of frequency, single chip, wireless collection
PDF Full Text Request
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