Design And Implementation Of Multi-Channel QCM Humidity Sensor Based On FPGA

Humidity measurement for modern production, life, whether it is food storage, crop planting, paper storage, or home, office, laboratory environment, which have an important role. Relative humidity sensor design has a lot of research. Quartz crystal microbalance humidity sensor measurement can be achieved through a combination of digital electronic devices. FPGA internal resource-rich, powerful circuit functions can be achieved, and the design cycle is short, the development costs low. This paper mainly quartz crystal humidity sensor measurement system, the design of the FPGA core components as QCM humidity sensor, humidity sensor simplifies the QCM system circuit structure.This paper analyzes and compares several QCM humidity sensor measurement method, on this basis, according to the characteristics of FPGA, developed a method to QCM oscillator circuit as the core of measurement methods; expounded the QCM humidity sensor measuring system works, system structure; completed by the74HC04crystal oscillator circuit, FPGA core measuring circuit and LCD1602LCD display circuit humidity measurement system consisting of the major hardware and software design.Making the overall physical measurement circuit, the choice of two kinds of moisture sensitive material based QCM humidity sensor, the relative humidity of collected amount of change in the resonant frequency of the experimental data; QCM humidity sensor test the stability of the short-term; analysis of the experimental results, experimental data using the least squares method for linear fitting; design of a linear least squares fitting segmented so fitting greatly improved; the end concludes the paper, the design of the inadequacies of the suggestions for improvement.After a humidity sensor system testing verified the feasibility of the design methods, proved that the system is able to achieve the desired design goals.