Research On Liquid Viscosity Measuring Instrument Based On Hall Sensor

Liquid viscosity is an important physical quantity to characterize the viscosity of liquid.It is also one of the main reference data for industrial production and scientific research and calculation.Mastering the theoretical knowledge of viscosity measurement is conducive to personnel training and social progress.Many physical experiment teaching in Colleges and universities in China include viscosity measurement experiment as a required experiment,and the experiment method mostly adopts the principle of falling ball method,which has the advantages of simple operation and obvious physical experiment phenomenon.However,there are some disadvantages,such as backward experimental instruments,inaccurate measurement results,and less liquid types.Therefore,it is of great practical significance to study a new experimental instrument.In this paper,first of all,the viscosity measurement methods and related instruments at home and abroad are introduced,and their advantages and disadvantages are analyzed and compared.This paper summarizes the reasons of using drop ball method in college physics teaching,points out the problems existing in the traditional drop ball method,puts forward a new method for measuring the viscosity of liquid based on the combination of Hall sensor and drop ball method,solves the problem that the traditional drop ball method can not measure the viscosity of non transparent liquid,and improves the measurement accuracy and intelligence at the same time.Then,this paper studies the hall sensor and the falling ball method theoretically,and gives the implementation scheme of the new measuring instrument system.The magnetic ball replaces the rigid ball of the traditional method.The falling process of the small ball makes the hall sensor produce Hall voltage.Through the processing of the Hall voltage signal,the falling speed of the small ball is obtained,and then the viscosity is obtained.And the components of the measurement system are selected and designed.Then the hardware circuit design,including power circuit,constant current source circuit,Hall signal amplifier circuit design,the internal resources of the microcontroller stm32f103zet6 selected in this paper are briefly introduced and related peripheral circuit design.Then the program is designed.This paper includes two parts:the lower computer and the upper computer.The lower computer program realizes the A/D conversion of Hall voltage signal,timing of the ball falling process,data transmission and transmission.The upper computer receives,processes and saves the received data by programming Lab VIEW software,and displays the wave form of Hall signal in real time,which makes the experimental phenomenon more intuitive.Finally,build a liquid viscosity measurement experimental platform to measure the viscosity of the liquid to obtain measurement data.In order to reduce the measurement error of experiment-related physical quantities,the theory of measurement inaccuracy is introduced.By curve fitting the measured data of the Hall signal,the speed when the ball is falling at a constant speed is calculated.Substitute the measurement data of each physical quantity to calculate the liquid viscosity value.Analyze and compare the experimental results,give the superiority of the viscosity measuring instrument in this paper and the sources of errors that affect the measurement results,and verify the feasibility of the experimental scheme.