基于单片机的智能电子秤的设计

基于单片机的智能电子秤的设计(论文12000字)
摘要：本设计研究了一款基于单片机的智能电子秤，该装置主要服务于人们日常生产、生活的质量测量与计价；以及实现了短信接收质量、计价信息等功能。本设计的基于单片机的智能电子秤主要有STC89C51单片机、电阻应变式称重传感器、HX711模块、SIM900A模块、
LCD12864和矩阵键盘等元器件构成。该智能电子秤的测量原理是：当被测物体放置在秤台上时，由于重力的作用使应变片发生形变、进而引起应变片电阻的变化，最终致使传感器的输出电压的变化；该电压经过放大与转换后由单片机进行处理，最后由LCD或短信来显示被测物体的重量与总价信息。本设计实现了重量显示，单价输入和总价计算，称量时的去皮、单价清零以及过载报警等功能；除此之外，本设计特别添加了短信发送功能，在智能电子秤称重完成后，按下“发短信”功能按键，智能电子秤就会把称重的信息以短信的形式发出。因此我设计的这款智能电子秤具有更为广阔的发展空间。

关键词：智能电子秤， 称重传感器， 单片机

Design of intelligent electronic scale based on single chip microcomputer
Abstract: The design researched a intelligent electronic scale based on single chip microcomputer. It is mainly to serve people's daily production , quality measurement and valuation of life ,also achieve the information receiving quality ,pricing information and other functions.  The design has taken the single chip microcomputer of STC89C51 ,resistor strain type weight sensors,HX711 module ,SIM900A module ,LCD 12864 and matrix keyboard etc.The measurement principle of intelligent electronic scale is:  when the measured object placed on the scale ,under the effect of gravity make the gage deform, so that the resistance strain gages change ,result in variation of sensor output voltage.Through application and conversion of voltage will be processed by single chip microcomputer .Finally the weight and total price information of measured object will be showed through LCD or message .It realized the function of the weight display,unit price input and total price calculation ,removing supernumerary weight,unit price cleared and overload auto alarm arc . In addition , the design of the SMS sent to send the function, in the smart electronic weighing after weighing, press the "send text messages" function keys, intelligent electronic scales will be weighing the message sent in the form of text messages. So I designed this smart electronic scale has a broader space for development.
Key words: intelligent electronic scale, weighing sensors,  microcontroller

目录    
1  引言    1
1.1 课题研究的意义与技术指标    1
1.2 称重技术的现状与发展    1
1.3 国内外电子秤的发展趋势    2
        1.3.1小型化.....................................................................................................................2
        1.3.2集成化.....................................................................................................................2
        1.3.3智能化.....................................................................................................................3
    1.4 本节小结............................................................................................ ...............................3
2 智能电子秤的总体设计    3
2.1 智能电子秤的组成部分    3
    2.2智能电子秤的工作原理    4
3智能电子秤各元器件介绍    5
3.1  单片机系统    5
3.1.1复位电路    5
3.1.2晶振电路    6
3.1.3掉电保护和检测电路    6
3.2 称重传感器    7
3.2.1 称重传感器选取    7
    3.2.2 应变式传感器    8
3.2.3 传感器的供电源    10
    3.3 HX711 A/D转换器    10
    3.4 发短信模块    11
    3.5 LCD显示器    11
    3.6 矩阵键盘    12
3.7 超载报警    12
    3.8 原理图..............................................................................................................................12
3.9 本章小结    13
4 智能电子秤的软件设计    13
4.1 主程序    15
4.2 中断程序    15
4.3 本章小结    15
5 电子秤误差的处理    16
5.1电子秤误差的来源    16
5.1.1 秤台的误差    16
5.1.2 应变式传感器的误差    16
5.1.3 二次仪表的误差    17
5.2 电子秤误差的计算    18
5.3电子秤误差的分配    19
5.4本章小结    19
6 结论    19
    6.1 总结    19
6.2展望    20
参考文献    21
致谢    22
附录：实物图    23