The Design Of Differential Capacitance Pressure Measurement System Based On AVR Microcontroller

This thesis designs a real-time measurement system with differential capacitive sensor which is controlled by AVR microcontroller.It can realize real-time accurate measurement of pressure with the advantages of high precision and sensitivity.Due to the traditional measuring instruments cannot meet the demands of modern measurement,the online monitoring devices need to be installed,which can be used for remote measurement and real-time transmission.This thesis is mainly based on AVR microcontroller.Meanwhile,sensor structure design,microcontroller technology and data communication are used in the remote pressure detection system,which can convert traditional recording mode into real-time pressure detection.This thesis realizes the automation and intellectualization of the pressure measurement,and greatly improves the work efficiency.This thesis designs a kind of differential capacitive sensor structure,through the research of the sensor model,we analyzed the results that the differential structure has the advantages of high sensitivity and small nonlinear than the ordinary structure.And the signal processing circuit is designed to convert the tiny capacitance of the sensor to the voltage signal that the microcontroller can collect.Many simulative and digital peripheral modules are integrated in a powerful-functioned new ATmega8535,which has strong data processing capacity.The data acquisition and operation are carried out by microcomputer,and the final data is transmitted to the host via RS-485.The software is programmed in C language,which makes the software more readable.Modularization design is used in the software,which is easy to program and debug.The characteristics of the research are small cubage,low cost,low power consumption,high reliability,etc,which can be used in many areas widely.