适用于51单片机的超声避障小车程序代码
利用HC-SR04超声波模块实现小车超声避障
演示视频：
头文件 BoeBot.h
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
#ifndef __BOEBOT_H__ #define __BOEBOT_H__ #include <at89x52.h> void delay_nms(int ms); void delay_nus(int us); #endif const unsigned char CONST_MILLISECONDCOUNT = 115; const unsigned char CONST_MICROSECONDDIVISER = 12; void delay_nms(int ms) { unsigned char i; while((--ms) >= 0) { for(i = 0;i < CONST_MILLISECONDCOUNT;i++); } } void delay_nus(int us) { us /= CONST_MICROSECONDDIVISER; while((--us) >= 0) {} } |
主程序 main.c
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 |
#include "BoeBot.h" sbit Led = P1^0; // Led指示 sbit Trig = P1^1; // 脉冲引脚 sbit Echo = P3^2; // 回波引脚 volatile unsigned short outcomeH,outcomeL; volatile char succeed_flag; void ConfigTimer() { TMOD = 0x1; //定时器0，16位工作方式 } void StartTimer() { TH0 = TL0 = 0; TR0 = 1; } void StopTimer() { TR0 = 0; } void ConfigExternal() { IT0 = 1; } void ConfigInterput() { ET0 = 1; EX0 = 1; } void EnableInterput() { EA = 1; } void DisableInterput() { EA = 0; } //距离计算公式 // distance = v * t / 2 // distance = 344 m/s * t * 12 / 11.0592 * us / 2 // = 344 mm/ms * t * 12/11.0592 / 1000 * ms / 2 // = 187 / 1000 * t mm // ~= t / 5.3 mm unsigned short ComputeDistance() { return (((outcomeH << 8) | outcomeL) / 5); } unsigned short FilterDistance(unsigned short distance) { static unsigned short distanceArray[5]; static char index = 0; char i; unsigned short sum; distanceArray[index] = distance; if((++index) == 5) { index = 0; } sum = 0; for(i = 0;i < 5;i++) { sum += distanceArray[i]; } return sum / 5; } void main() { unsigned short distanceMM; ConfigExternal(); ConfigTimer(); ConfigInterput(); while(1) { // 启动定时器 EnableInterput(); StartTimer(); succeed_flag = 0; // 产生一个20us的脉冲，在Trig引脚 Trig = 1; delay_nus(20); Trig = 0; // 停止定时器 while(!succeed_flag); StopTimer(); DisableInterput(); // 计算距离，并根据阈值点亮Led distanceMM = ComputeDistance(); //Led = (FilterDistance(distanceMM) < 300 ? 0 : 1); Led = (distanceMM < 200 ? 0 : 1); delay_nms(10); } } //外部中断0，用做判断回波电平 void IE0_Handler(void) interrupt IE0_VECTOR // 外部中断是0号 { outcomeH = TH0; // 取出定时器H值 outcomeL = TL0; // 取出定时器L值 succeed_flag = 1; // 设置测量成功标记 IE0 = 0; } void TF0_Handler(void) interrupt TF0_VECTOR // 定时器0 {} |