一、原件清单

  • Arduino Uno开发板
  • L293D
  • 轮子 (4x)
  • 直流电机 (4x)
  • 伺服电机sg90
  • 超声波传感器
  • 18650 锂电池 (2x)
  • 18650 插针式电池盒子
  • 跳线
  • 亚克力板
  • 三脚拨动开关

二、硬件连接

  1. L293D直流电机驱动模块与Arduino兼容,模块的0~13、gnd、以及ARef引脚直接连接对应Arduino的引脚,另一侧同样对应连接。

  2. 图中标记为L293D的四个H桥,可分别连接四个直流电机。
    L293D

  3. 超声波传感器的Vcc连接L293D的+5v,Gnd连接L293D的Gnd,Trig连A0,Echo连接A1。

  4. 伺服电机直接连接L293D板子的伺服电机端口。

  5. 两节18650锂电池串联接入L293D的外部供电。

三、程序代码

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#include <AFMotor.h>  
#include <NewPing.h>
#include <Servo.h>

#define TRIG_PIN A0
#define ECHO_PIN A1
#define MAX_DISTANCE 200
#define MAX_SPEED 190 // sets speed of DC motors
#define MAX_SPEED_OFFSET 20

NewPing sonar(TRIG_PIN, ECHO_PIN, MAX_DISTANCE);

AF_DCMotor motor1(1, MOTOR12_1KHZ);
AF_DCMotor motor2(2, MOTOR12_1KHZ);
AF_DCMotor motor3(3, MOTOR34_1KHZ);
AF_DCMotor motor4(4, MOTOR34_1KHZ);
Servo myservo;

boolean goesForward=false;
int distance = 100;
int speedSet = 0;

void setup() {

myservo.attach(10);
myservo.write(180);
delay(2000);
distance = readPing();
delay(100);
distance = readPing();
delay(100);
distance = readPing();
delay(100);
distance = readPing();
delay(100);
}

void loop() {
int distanceR = 0;
int distanceL = 0;
delay(40);

if(distance<=15)
{
moveStop();
delay(100);
moveBackward();
delay(300);
moveStop();
delay(200);
distanceR = lookRight();
delay(200);
distanceL = lookLeft();
delay(200);

if(distanceR>=distanceL)
{
turnRight();
moveStop();
}else
{
turnLeft();
moveStop();
}
}else
{
moveForward();
}
distance = readPing();
}

int lookRight()
{
myservo.write(50);
delay(500);
int distance = readPing();
delay(100);
myservo.write(115);
return distance;
}

int lookLeft()
{
myservo.write(170);
delay(500);
int distance = readPing();
delay(100);
myservo.write(115);
return distance;
delay(100);
}

int readPing() {
delay(70);
int cm = sonar.ping_cm();
if(cm==0)
{
cm = 250;
}
return cm;
}

void moveStop() {
motor1.run(RELEASE);
motor2.run(RELEASE);
motor3.run(RELEASE);
motor4.run(RELEASE);
}

void moveForward() {

if(!goesForward)
{
goesForward=true;
motor1.run(FORWARD);
motor2.run(FORWARD);
motor3.run(FORWARD);
motor4.run(FORWARD);
for (speedSet = 0; speedSet < MAX_SPEED; speedSet +=2) // slowly bring the speed up to avoid loading down the batteries too quickly
{
motor1.setSpeed(speedSet);
motor2.setSpeed(speedSet);
motor3.setSpeed(speedSet);
motor4.setSpeed(speedSet);
delay(5);
}
}
}

void moveBackward() {
goesForward=false;
motor1.run(BACKWARD);
motor2.run(BACKWARD);
motor3.run(BACKWARD);
motor4.run(BACKWARD);
for (speedSet = 0; speedSet < MAX_SPEED; speedSet +=2) // slowly bring the speed up to avoid loading down the batteries too quickly
{
motor1.setSpeed(speedSet);
motor2.setSpeed(speedSet);
motor3.setSpeed(speedSet);
motor4.setSpeed(speedSet);
delay(5);
}
}

void turnRight() {
motor1.run(FORWARD);
motor2.run(FORWARD);
motor3.run(BACKWARD);
motor4.run(BACKWARD);
delay(500);
motor1.run(FORWARD);
motor2.run(FORWARD);
motor3.run(FORWARD);
motor4.run(FORWARD);
}

void turnLeft() {
motor1.run(BACKWARD);
motor2.run(BACKWARD);
motor3.run(FORWARD);
motor4.run(FORWARD);
delay(500);
motor1.run(FORWARD);
motor2.run(FORWARD);
motor3.run(FORWARD);
motor4.run(FORWARD);
}

四、注意事项

1. 使用18650作外部供电时,切记不要连反了线,否则会有烧芯片的风险。
2. 伺服电机应该选择限制旋转180°的sg90,而不能选择mg90一类的360舵机,原因是后者只能调正反转和速度,而不能像前者一样旋转固定的角度。
3. Arduino程序烧录时,有三个必要的支持库需要下载,下面是下载链接以及安装方式。

AFMotor Library https://learn.adafruit.com/adafruit-motor-shield/library-install
NewPing Library https://github.com/livetronic/Arduino-NewPing
Servo Library https://github.com/arduino-libraries/Servo.git

点击 sketch(项目) >> Include Library(加载库) >> Add .ZIP File(添加zip.文件),把你下载好的库文件添加进去。

五、成品展示

智能车.jpg