前言

考虑到之前那篇博客写的太简略，也只给了一个最终代码，比较容易让人看不懂。本篇主要写一些不同功能函数的代码讲解，要看整体部分的请前往我的另一篇博客—基于Arduino(MEGA2560)的智能物流小车项目

测试部分

▶ 此代码用于测试车轮是否正确连线，以及不同高低电平的小车行进状态。
▶ 更改运动控制函数的高低电平(HIGH,LOW)，保证小车烧录代码后能依次执行向前、向后、向左、向右、停止四个运动状态。
▶ 若不是正常顺序，更改代码即可，并且记住自己小车的四个状态的高低电平。

#include <Servo.h>
//定义五中运动状态
#define STOP      0
#define FORWARD   1
#define BACKWARD  2
#define TURNLEFT  3
#define TURNRIGHT 4
//定义需要用到的引脚
int leftMotor1 = 14;
int leftMotor2 = 15;
int rightMotor1 = 16;
int rightMotor2 = 17;
int leftPWM = 2;
int rightPWM = 3;
void setup() {
  // put your setup code here, to run once:
  //设置控制电机的引脚为输出状态
  pinMode(leftMotor1, OUTPUT);
  pinMode(leftMotor2, OUTPUT);
  pinMode(rightMotor1, OUTPUT);
  pinMode(rightMotor2, OUTPUT);
  pinMode(leftPWM, OUTPUT);
  pinMode(rightPWM, OUTPUT);
}

void loop() {
  int cmd;
  for(cmd=0;cmd<4;cmd++)
  //依次执行向前、向后、向左、向右、停止四个运动状态
  {
    motorRun(cmd,255);  
    delay(1000);//每个命令执行2s 
  } 
}
//运动控制函数(注意！需要更改的地方为此处)
void motorRun(int cmd,int value)
{
  analogWrite(leftPWM, value);  //设置PWM输出，即设置速度
  analogWrite(rightPWM, value);
  switch(cmd){
      case 0:
      Serial.println("FORWARD"); //输出状态
      digitalWrite(leftMotor1, HIGH);
      digitalWrite(leftMotor2, LOW);
      digitalWrite(rightMotor1, LOW);
      digitalWrite(rightMotor2, HIGH);
      break;
      case 1:
      Serial.println("BACKWARD"); //输出状态
      digitalWrite(leftMotor1, LOW);
      digitalWrite(leftMotor2,HIGH );
      digitalWrite(rightMotor1,HIGH );
      digitalWrite(rightMotor2,LOW);
      break;
      case 2:
      Serial.println("TURN LEFT"); //输出状态
      digitalWrite(leftMotor1, HIGH);
      digitalWrite(leftMotor2, LOW);
      digitalWrite(rightMotor1, LOW);
      digitalWrite(rightMotor2, LOW);
      break;
    case 3:
      Serial.println("TURN RIGHT"); //输出状态
      digitalWrite(leftMotor1, LOW);
      digitalWrite(leftMotor2, LOW);
      digitalWrite(rightMotor1, LOW);
      digitalWrite(rightMotor2, HIGH);
      break;
     default:
      Serial.println("STOP"); //输出状态
      digitalWrite(leftMotor1, LOW);
      digitalWrite(leftMotor2, LOW);
      digitalWrite(rightMotor1, LOW);
      digitalWrite(rightMotor2, LOW);
  }
}

循迹部分

#include <Servo.h>

#define STOP      0
#define FORWARD   1
#define BACKWARD  2
#define TURNLEFT  3
#define TURNRIGHT 4

int leftMotor1 = 14; //直流电机引脚
int leftMotor2 = 15;
int rightMotor1 = 16;
int rightMotor2 = 17;

int trac1 = 11; //车头四个灰度传感器引脚
int trac2 = 10; //从车头方向的最右边开始排序
int trac3 = 9; 
int trac4 = 8; 

int leftPWM = 3; //驱动PWM引脚
int rightPWM = 2;

int data[4]; //记录灰度读取值(0/1)

void setup() {
  //串口初始化
  Serial.begin(9600); 
  //测速引脚初始化
  pinMode(leftMotor1, OUTPUT);
  pinMode(leftMotor2, OUTPUT);
  pinMode(rightMotor1, OUTPUT);
  pinMode(rightMotor2, OUTPUT);
  pinMode(leftPWM, OUTPUT);
  pinMode(rightPWM, OUTPUT);
  //寻迹模块引脚初始化
  pinMode(trac1, INPUT);
  pinMode(trac2, INPUT);
  pinMode(trac3, INPUT);
  pinMode(trac4, INPUT);
}

 //运动控制函数
 //确保与测试部分测试好的函数相同
void motorRun(int cmd,int value)
{
  analogWrite(leftPWM, value);  //设置PWM输出，即设置速度
  analogWrite(rightPWM, value);
  switch(cmd){
    case FORWARD:
     Serial.println("FORWARD"); //输出状态
      digitalWrite(leftMotor1, LOW);
      digitalWrite(leftMotor2, HIGH);
      digitalWrite(rightMotor1, LOW);
      digitalWrite(rightMotor2, HIGH);
      break;
      case BACKWARD:
      Serial.println("BACKWARD"); //输出状态
      digitalWrite(leftMotor1, HIGH);
      digitalWrite(leftMotor2, LOW);
      digitalWrite(rightMotor1, HIGH);
      digitalWrite(rightMotor2, LOW);
      break;
     case TURNLEFT:
      Serial.println("TURN LEFT"); //输出状态
      digitalWrite(leftMotor1, LOW);
      digitalWrite(leftMotor2,HIGH);
      digitalWrite(rightMotor1,HIGH);
      digitalWrite(rightMotor2,LOW);
      break;
     case TURNRIGHT:
      Serial.println("TURN RIGHT"); //输出状态
      digitalWrite(leftMotor1, HIGH);
      digitalWrite(leftMotor2, LOW);
      digitalWrite(rightMotor1, LOW);
      digitalWrite(rightMotor2, HIGH);
      break;
     default:
      Serial.println("STOP"); //输出状态
      digitalWrite(leftMotor1, LOW);
      digitalWrite(leftMotor2, LOW);
      digitalWrite(rightMotor1, LOW);
      digitalWrite(rightMotor2, LOW);
  }
}

//循迹函数
void tracing()
{
  data[0] = digitalRead(11);
  data[1] = digitalRead(10);
  data[2] = digitalRead(9);
  data[3] = digitalRead(8);
   if((!data[0] && data[1] && data[2] & 4& !data[3]))  
  {
    motorRun(FORWARD,220); 
  }
  
  else if(data[0] && data[1] && data[2] && data[3])
  {
    motorRun(FORWARD,220);
  }
  
  /*else if(!data[0] && data[1] && data[2] && data[3])
  {
    motorRun(TURNLEFT, 100,100);
  }   上坡微调*/ 

  else if(data[2] || data[3])  
  {
    motorRun(TURNLEFT,255);
  }

    else if(data[0] || data[1])  
  {
    motorRun(TURNRIGHT,255);
  }

  /* else if(!data[0] && !data[1] && data[2] &&!data[3])  
  {
    motorRun(TURNLEFT,220);
  }
   
   else if(!data[0] && !data[1] && data[2] && data[3])  
  {
    motorRun(TURNLEFT,220);
  }

  else if(!data[0] && !data[1] && !data[2] && data[3])  
  {
    motorRun(TURNLEFT,220);
  }

    else if(!data[0] && data[1] && !data[2] && !data[3])  
  {
    motorRun(TURNRIGHT,220);
  }

  else if(data[0] && data[1] && !data[2] && !data[3])  
  {
    motorRun(TURNRIGHT,220);
  }*/
  Serial.print(data[0]);
  Serial.print("---");
  Serial.print(data[1]);
  Serial.print("---");
  Serial.print(data[2]);
  Serial.print("---");
  Serial.print(data[3]);
  Serial.print("---");
}

void loop() 
{
  tracing();
}

超声波测距部分

const int TrigPin = 5; 
const int EchoPin = 4; // 发射，接收引脚
float cm; 
void setup() 
{ 
Serial.begin(9600); 
pinMode(TrigPin, OUTPUT); 
pinMode(EchoPin, INPUT); 
} 
void loop() 
{ 
digitalWrite(TrigPin, LOW); //低高低电平发一个短时间脉冲去TrigPin 
delayMicroseconds(2); 
digitalWrite(TrigPin, HIGH); 
delayMicroseconds(10); 
digitalWrite(TrigPin, LOW); 


cm = pulseIn(EchoPin, HIGH) / 58.0; //将回波时间换算成cm 
cm = (int(cm * 100.0)) / 100.0; //保留两位小数 
Serial.print(cm); 
Serial.print("cm"); 
Serial.println(); 
delay(1000); 
}

避障部分

▶ 此代码用于检测小车运动过程中，超声波是否在正常工作。有时候通过串口监视超声波能正确读出距离，小车运动时超声波就不会正常工作。
▶ 此代码为小车一直前进，检测到障碍物时，执行左转-前行-右转-大前行-右转-前行-左转从而达到避开障碍物的目的且车头回正。

#include <Servo.h>

#define STOP      0
#define FORWARD   1
#define BACKWARD  2
#define TURNLEFT  3
#define TURNRIGHT 4

int leftMotor1 = 14;
int leftMotor2 = 15;
int rightMotor1 = 16;
int rightMotor2 = 17;

int leftPWM = 2;
int rightPWM = 3;

Servo myServo;  //舵机

int inputPin=4;   // 定义超声波信号接收接口
int outputPin=5;  // 定义超声波信号发出接口

int dis;
float cm; 

void setup() {
  // put your setup code here, to run once:
  //串口初始化
  Serial.begin(9600); 
  //舵机引脚初始化
  myServo.attach(4);
  //测速引脚初始化
  pinMode(leftMotor1, OUTPUT);
  pinMode(leftMotor2, OUTPUT);
  pinMode(rightMotor1, OUTPUT);
  pinMode(rightMotor2, OUTPUT);
  pinMode(leftPWM, OUTPUT);
  pinMode(rightPWM, OUTPUT);
  //超声波控制引脚初始化
  pinMode(inputPin, INPUT);
  pinMode(outputPin, OUTPUT);
}
void motorRun(int cmd,int value)
{
  analogWrite(leftPWM, value);  //设置PWM输出，即设置速度
  analogWrite(rightPWM, value);
  switch(cmd){
    case FORWARD:
     Serial.println("FORWARD"); //输出状态
      digitalWrite(leftMotor1, HIGH);
      digitalWrite(leftMotor2, LOW);
      digitalWrite(rightMotor1, HIGH);
      digitalWrite(rightMotor2, LOW);
      break;
     case