設(shè)計任務(wù)（車輛從起跑線出發(fā)（出發(fā)前，車體不得超出起跑線C~D區(qū)（3～6米）以低速行駛，通過時間不低于10s；第二個路程D～E區(qū)（2米）以高速行駛，通過S型控制：如（2）（SS型鐵片跑度并通過LCD顯示出來。方案比較與選擇根據(jù)設(shè)計任務(wù)要求，并且根據(jù)自己的需要而附加的功能，該電路的總體框圖可分為幾個基本的模塊，框圖如（圖3）所示：（如（圖4）所示：（采用1602LCD，由單片機的總線模式連接。為節(jié)約電源電量并且不影響LCD的功能，LCD的背光用單片機進行控制，使LCD的背光在小車行駛的過程中不亮，因為不必看其顯示；在其它需要看顯示的內(nèi)容的時候LCD背光亮。量速度的作用。霍爾元件具有體積小，頻率響應(yīng)寬度大，動態(tài)特性好，對電路要求一定強度的磁場起作用，能力強，因此可以在車輪上安裝小磁鐵，而將霍爾器件采用紅外傳感器進速。但無論是反射式紅外傳感器還是對射式紅外傳感器，他們對都對環(huán)境要求較高，易受外部環(huán)境的影響，穩(wěn)定性不高，且價格較為昂貴。通過對方案1、方案2的比較其優(yōu)缺點，綜合多方面因素決定選用方案1，其原理圖接線如（圖5）（理簡單，成本低，加速能力強，但功率損耗大，特別是低速大轉(zhuǎn)距運行時，通過電阻R 方案的優(yōu)點是電路較為簡單,缺點是繼電器的響應(yīng)時間慢,易損壞,較短,可靠性不高。H關(guān)狀態(tài)，精確調(diào)整電機轉(zhuǎn)速。這種電路由于工作在管子的飽和截止模式下，效率非常高；H（模式選擇模塊通過一個74LS00走完路程小車停止后還可以通過按鈕選擇想要在LCD片，即第一次轉(zhuǎn)彎后若感應(yīng)到的是錯誤的方向，則小車會后退自動調(diào)整方向，沿著S型LCD程序框圖圖系統(tǒng)的具體設(shè)計與實現(xiàn)采用1602LCD，由單片機的總線模式連接。為節(jié)約電源，LCD的背光用單片機進行控秒小車轉(zhuǎn)動圈數(shù)，再測量出小車車輪周長即可計算出小車當(dāng)前速度，累加可得到當(dāng)V

22 RST1（鈕控制。原理圖如（圖9）所示：（最小系統(tǒng)圖該系統(tǒng)主要用到的是單片機，所以主要的部分是最小系統(tǒng)圖，該最小系統(tǒng)圖如（最終PCB板圖最小系統(tǒng)的簡潔以及容易看懂，外部擴展電路不在最小系統(tǒng)圖上顯示。）分別如（11、（（系統(tǒng)程序#include #define#define#define#define#define#define#defineData#defineCmd//0表正常速//1表低//2表高 全局函數(shù) WriteCmd(charWriteDharvoid voidSetXY(charx,chary); voidDisplaySingleChar(charx,chary,charcchar); voidDisplayString(charx,chary,char*str); voidDelay(unsignedint voidDelayUs(unsignedint bit void void void voidINTInit(void); void voidvoid

SpeedCount=Speed=Distance=0.0;

shortBack0=0; void{Starting...DisplayString(0x0,1,"DesignedBy202"); DisplayString(0x0,0,"ChooseTheMode");DisplayString(0x0,1,"youwant. { LineMode"); while {if(Next==True) if { }if {}if {DisplayString(0x0,0,"CurveMode"); {if(Next==True) if {}}}if {}if { {if{}}}if{}if{}} if(SelectedMode==Line&&AutoMode==0){DisplayString(0x0,0,"NowChoosea");DisplayString(0x0,1,"kindofSpeed");{ {if(Next==True) if { }if {}if{ LowSpeed"); {if(Next==True) if { }}}if {}if{DisplayString(0x0,0,"HighSpeed"); {if(Next==True) if {Thx[0]=0xe0;Tlx[0]=0xc0;//8msThx[1]=0xe0;Tlx[1]=0xc0;//8msThx[2]=0x63;Tlx[2]=0xc0;//40msThx[3]=0xec;Tlx[3]=0x78;//5ms}}}if {}if {}}} if{

DisplayString(0x0,0,"ChoosenModeis");DisplayString(0x0,1,"Line");Delay(50);}if{DisplayString(0x0,0,"ChoosenModeis");DisplayString(0x0,1,"Curve");}if{DisplayString(0x0,0,"ChoosenModeis }if{if{DisplayString(0x0,0,"ChoosenSpeedis");DisplayString(0x0,1,"Normal");}if{DisplayString(0x0,0,"ChoosenSpeedis");DisplayString(0x0,1,"Low");Delay(50);}if{DisplayString(0x0,0,"ChoosenSpeedis");DisplayString(0x0,1,"High");Delay(50);}} DisplayString(0x0,0,"LeftTimesToGo");while(ReadyToGo--){} DisplayString(0x0,1,"Designedby{ {{case0case1

case2:{}}{

default:break; {}

{}{

{}

{

{}{

{}{}}}}}}if{}} if {{if(GoToChoosingDisplay==True)DisplayString(0,1,"Costed");if(LowSpeedArea1PassTime>9) if(GoToChoosingDisplay==True)DisplayString(0,0,"HighSpeedAreaDisplayString(0,1,"Costed");if(HighSpeedAresTime>9) if(GoToChoosingDisplay==True)DisplayString(0,0,"LowSpeedArea2");DisplayString(0,1,"Costed");if(LowSpeedArea2PassTime>9) }}/*----------------菜單選擇你想要看的內(nèi)容--總時間、總路程以及平均速 DisplayString(0x0,0,"NowChoosewhatDisplayString(0x0,1,"youwanttosee{ CostedTime"); {}if(SelectedShow==True){DisplayString(0,0,"CostedTimeis"); }if {DisplayString(0x0,0,"AVGSpeed");DisplayString(0x0,1,"NextShow"); } {if}if{ if(AVGSpeedShow==False) }if DisplayString(0x0,0,"TotalDistance }}if {if(ReturnSelection==True) if{DisplayString(0,0,"TheAVGSpeedis"); }}if {} {}if(Next==True){ if(TotalDistanceShow==True)if {DisplayString(0x0,0,"TotalDistance");DisplayString(0x0,1,"NextShow"); }}if {if(ReturnSelection==True) if{if {DisplayString(0,0,"TheAVGSpeedis"); }if{ }}}if {}{

}if {if{DisplayString(0x0,0,"TotalDistance");DisplayString(0x0,1,"NextShow"); }}if{if(ReturnSelection==True) if{if{;//按 }}}if {}{

}if {if {}}if{if(ReturnSelection==True) if{if{ }}} {}if{}if{}}} void{ } 設(shè)置LCD為寫命令模式 void{}void{}void{} voidWriteCmd(char{ }voidWriteDhar{}void{}voidSetXY(charx,char{if}voidDisplaySingleChar(charx,chary,char{}voidDisplayString(charx,chary,char{{}}bit{return(bit)(P1&}voidDelay(unsignedint{

延時函 unsignedinttimeCounter=for(timeCounter=time;timeCounter>0;timeCounter--)}voidDelayUs(unsignedint{unsignedinttimeCounter=for(timeCounter=0;timeCounter<time;timeCounter} void{if(Area0<}void{ }void{

顯示時 charPassTime1=0x30;charPassTime2=0x30;charPassTime3=0x30;charif {}elseif((int)(PassTime*100100&&(int)(PassTime*100)10001s而未夠{}{}

if((int)(PassTime*100)<{}{}

} void{int intif((int)(Distance/PassTime*100)<{}{}

} 顯示路 void{intDistance1=0x30;intDistance2=0x30;intDistance3=0x30;intDistance4=0x30;if((int)(Distance*100)<{}elseif((int)(Distance*100)>100&&(int)(Distance*100)<{}{

}if((int)(Distance*100)<{}{}}

void{ }void{ }void{ } 外部中斷 voidSpeedINT(voidinterrupt {if(SelectedAll==False) if(Running==True) if(ChoosingDisplay==True) } 外部中斷 voidCtrSpeedINT(voidinterrupt {if {if(IsSelectingMode==True) if(IsSelectingSpeed==True) }if {if { }if ififif {{case5case10default}{

if {if(Area0==5)} {}}}if{}if{}} voidTime0INT(void)interrupt {{ case2case3:Distance=Distance-case4:SecondDistance=Distance-PrepareDistance-case5:ThirdDistance=Distance-PrepareDistance-Distance-SecondDistance;break;default:break;}{case0

case1

{}case2:{}}{

Thx[0]=Thx[1]=((High&0xf0)>>8);Tlx[0]=Tlx[1]=(High&0x0f);Th