| Food is very important necessities to human beings.Food quality is closelyrelated to human life. There are many factors affecting the quality of food.However,grain moisture is a major factor of them. So measure grain moisture, keepfood moisture in a reasonable scope has a profound significance.Nowadays,the researchof the grain moisture measurement system has been paid more and more attention by alot of people. It also has been a very important and hot research subject.In this paper a new and fast measurement technology for grain moisturecontent was proposed. We designed the hardware system and software systembased on Atmega128produced by Atmel company.We use capacitance method tocollect water and convert grain moisture value into the capacitance value ofcapacitance sensor. This design uses555oscillation circuit as the core ofhardware system，using the frequency of the pulse which send out by MCUtimer/counter acquisition oscillation circuit.On the basis of a large number offield experiment,we record the humidity and the frequency value,set up theappropriate mathematical model and get the function between the humidity andthe frequency value.Specific research is as follows.(1)Analyzing the advantages and disadvantages of all kinds of grain moisturedetection method,doing a brief introduction for the current research status ofgrain moisture detection.(2)Designing the hardware of system,the main contents are the design ofcapacitance sensor,555oscillation circuit design, the design of the button andthe design of the power supply.(3)Designing the software of system,the main contents are the program designof the timer/counter,key,frequency and humidity measurement,temperature and12864display.(4)Introducing the experiment process,establishing and analyzingmathematical model of grain moisture.(5)Introducing and analyzing influence factors of the measurementresult,giving the inadequacies of this design and the prospects for futureresearch and design. |
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