Research And Design Of Humidity Sensor System Of Quartz Tuning Fork With Polyvinyl Alcohol Material

Humidity detection technology plays an important role in climate monitoring,smart manufacturing,smart agriculture,aerospace and other fields.Quartz Crystal Microbalance(QCM)humidity sensor for megahertz frequency level output,although it has the advantages of high sensitivity and fast response speed,but it has a large volume,high power consumption,and the output signal requires a special shielded cable connection and other problems.Therefore,in this paper,by investigating the current state of technology and application fields at home and abroad,a polyvinyl humidity(Polyvinyl Alcohol,PVA)as a moisture sensitive material combined with a quartz tuning fork resonator is proposed to design a digital humidity sensor.The sensor has the characteristics of small size,low power consumption and high sensitivity.This paper uses a combination of theoretical analysis and experimental verification to research and design sensors.First,the working mechanism of the quartz tuning fork resonator is explained.Based on the analysis of the moisturesensing characteristics of the PVA material and water molecules,PVA is coated on the top of the quartz tuning fork arm,the water molecules are adsorbed and desorbed by PVA to cause a slight change in the quality of the tuning fork arm,and causes a shift in the resonance frequency of the quartz tuning fork.According to the humidity sensitivity characteristic between the change in the mass of the quartz tuning fork arm and the resonance frequency shift of the quartz tuning fork,a humidity humidity characteristic curve of the sensor is established through simulation to complete the humidity sensor mechanism Theoretical analysis.Secondly,the sensor structure is packaged by the ABS shell and rosin resin to complete the sensor prototype design,and the quartz frequency tuning fork resonance frequency oscillation and frequency division circuit is combined with the microprocessor to realize the detection of the humidity frequency signal,and the network node unit is used to complete the Conversion of humidity parameters and construction of data visualization system.Finally,the sensor was calibrated by setting up a constant temperature and humidity test system.The test results show that the sensor has a sensitivity of ab out 1.14 Hz /(%RH)in the range of 11.3% RH to 75.4% RH at a room temperature of 20 ° C.The non-linear error is about 5%,the hysteresis error is 13.8%,and the repeatability error is 4.9%,and the response time and recovery time are about 60 s and 105 s,which has good repeatability.The polyvinyl alcohol-based quartz tuning fork humidity sensor system designed in this paper can realize the detection of humidity signals,has the characteristics of high sensitivity,good stability,etc.,and can perform real-time monitoring of humidity parameters by remote visualization,it can provide meaningful reference for the design and application of other quartz tuning fork resonance sensors.