1/32数字电子秤摘要本课程设计制作的电子称以89c52单片机为控制器，利用电阻应变式称重传感器的全桥式称重原理，及通过受力改变内部应变片的阻值使，电路的输出电压与传感器所受压力成线性关系，建立相应的数学模型。设计思路为将传感器所测得的电压值进行模数转换，并将此转换数值与具体重量相对应，再将最终数值通过1602液晶屏显示。由于此称重传感器在受压时形变量小，使输出电压信号十分微弱，于是本设计采用运放连接成差分放大电路将其微弱的信号进行放大处理，再通过AD0809将此模拟量转化为数字量，输送给单片机，由单片机来控制其重量的显示。关键词：89c52，全桥式称重传感器，AD0809。TheDigitalElectronicScaleAbstract：Thedesignofdigitalelectronicscaleusesthechip89c52asitsmonitor,andsetsupthemathematicalmodelthatbasestheprinciplesofFullBridgesystemweighingsensor,whosecharacteristicistheoutputvoltagechangeislinearitywiththepressureonthefoilgage.Thedesignthoughtismakingtheanalogoutputofvoltageintodigitalquantity,thenmakeitmatchwiththeweightspecific,finallydisplaythedatathroughthe1602LCD.Asthechangeoftheresistancevalueonfoilgageisverysmallsoastheoriginaloutputvoltage,sousestheoperationalamplifiertoamplifythesignalandtheninputtotheAD0809chiptotransformitintodigitalquantity,whichfinallyinputtedinto89c52microcontroller,andthe89c52microcontroller’staskismanipulatingthe1/322/32dateandmakingtheLCDdisplaythenumber.Keywords：89c52microprocessor,semi-bridgesystemweighingsensor,AD0809chip.目录1．系统设计.....................................................................................31.1设计要求................................................................................31.2总体设计方案........................................................................31.2.1设计思路......................................................................31.2.2方案论证与比较..........................................................31.2.3模块组成......................................................................52．硬件电路设计.............................................................................62.1模拟信号处理部分................................................................62.1.1信号采集部分.............................................................62.1.2信号的放大处理.........................................................72.2模数转换...............................................................................102.3数字信号的处理部分...........................................................112.3.1单片机控制LCD显示.............................................123．软件设计...................................................................................144．系统测试.......................................................................................154.1测试使用的仪器及工具.......................................................154.2指标测试及测试结果...........................................................154.3结果分析...............................................................................155．结论...............................................................................................16参考文献.............................................................................................17附录1．元器件清单:........................................................................18附录二电路原理图及印制板图.......................................................191．信号放大部分电路原理图及PCB图......
