LED自适应调光系统设计

（2011届）毕业设计题目：基于AVR单片机的LED自适应调光系统设计姓名：专业：电子信息工程班级：学号：指导教师：导师职称：年月日I基于AVR单片机的LED自适应调光系统设计摘要作为一种光源，调光是很重要的。不仅是为了在家居中得到一个更舒适的环境，在今天来说，减少不必要的电光线，以进一步实现节能减排的目的是更加重要的一件事。而且对于LED光源来说，调光也是比其他荧光灯、节能灯、高压钠灯等更容易实现，所以更应该在各种类型的LED灯具中加上调光的功能。自适应调光系统硬件电路由四个部分组成：感光电路、AD转换电路、单片机控制电路、发光二极管驱动电路。软件部分采用PID算法，自动调节环境光照度。本设计以89C51单片机为控制器，利用光敏电阻采集环境光照度，采用脉宽调制方式调节三极管，进而调节LED的发光亮度，最终维持环境光照度在一个设定的水平。关键词：LED，自适应调光，AVR单片机,PID算法IILEDAdaptiveDimmingSystemBasedonAVRAbstractThequalityofdimmingoflightsourceisveryimportant.Itisnotonlyforabetterenvironmentathome.Atpresent,itisalsoanevenmoreimportantissuetolessenwasteofunnecessaryelectriclightandfurtherachievethegoalofenergysavingandemissionreduction.What’smore,forlightsourceofLED,itiseasiertoadjustbrightnessthanfluorescentlamp,energysavinglamp,highpressuresodiumlampandotherkindsoflamps.Therefore,we’dbetteraddthefunctionofbrightness-adjustingtovariouskindsofLEDlamps.Thehardwareofadaptiveadjustableoptical-intensitysystemisconsistedoffourparts.Theyarephotosensitivecircuit,ADchange-overcircuit,single-chipmicrocomputercontrolcircuit,andLEDdrivingcircuit.AndthesoftwareofthesystemmakesuseofPIDalgorithmtoadjustbrightnessofenvironmentautomatically.Thisdesigntakes89C51SCMascontroller,usephotoconductiveresistancetocollectluminanceoftheenvironment.Andthedesigneradoptpulsewidthmodulationmodetoadjusttriode,whichcanhelpadjustbrightnessofLEDtokeepintensityofilluminationoftheenvironmentatasetlevel.Keywords:LED,adaptivedimmer,AVR,PIDIII目录摘要............................................................................................................................IAbstract.........................................................................................................................II1绪论............................................................................................................................11.1LED的国内外研究现状..................................................................................11.2课题的意义.......................................................................................................22系统设计原理.............................................................................................................32.1总体设计方案..................................................................................................32.2系统驱动方式选择...........................................................................................42.3LED驱动设计注意点.......................................................................................43硬件设计....................................................................................................................63.1电源电路...........................................................................................................63.2感光电路..........................................................................................................73.2.1LED发光原理.........................................................................................93.3手动控制电路...................................................................................................93.4单片机控制电路............................................................................................103.4.1AT89C51简介...................................................................................113.4.2ADC0832简介..................................................................................123.4.3单片机控制电路................................................................................143.4.4AD转换电路........................................................................................153.4.5PID控制的原理和特点....................................................................153.5晶振电路.........................................................................................................173.6发光二极管驱动电路.....................................................................................174软件设计..................................................................................................................184.1系统流程图.....................................................................................................184.2初始化............................................................................................................194.3读取当前亮度................................................................................................194.4手动调节........................................................................................................204.5PWM调制亮度调节......................................................................................205总结与展望..............................................................................................................235.1总结................................................................................................................235.2展望...............................................................................................................23参考文献......................................................................................................................24致谢.............