1. 硬體

Arduino控制板：1個；

數碼管：1個;

杜邦線：若干;

1.1 接線方式

參考如下：

 a = 1; tb = 2;  c = 3;d = 4; e = 5; f = 6; g = 7; dp = 8;

注意：上面的這些都需要串聯電阻。

//設定陽極介面

d4 = 9; d3 = 10; d2 = 11; d1 = 12;

注意：這些可以直接連線到Arduino上。

來張實際的照片（略麻煩）：

2 程式

#include <ros.h>
#include <std_msgs/Empty.h>



int a = 13;
int b = 2;
int c = 3;
int d = 4;
int e = 5;
int f = 6;
int g = 7;
int dp = 8;
//設定陽極介面
int d4 = 9;
int d3 = 10;
int d2 = 11;
int d1 = 12;


///////////////////////////////////////////////////////////////
void WeiXuan(unsigned char n)//
{
    switch(n)
     {
  case 1: 
    digitalWrite(d1,HIGH);
    digitalWrite(d2, LOW);
    digitalWrite(d3, LOW);
    digitalWrite(d4, LOW);   
   break;
   case 2: 
    digitalWrite(d1, LOW);
    digitalWrite(d2, HIGH);
    digitalWrite(d3, LOW);
    digitalWrite(d4, LOW); 
      break;
    case 3: 
      digitalWrite(d1,LOW);
     digitalWrite(d2, LOW);
     digitalWrite(d3, HIGH);
     digitalWrite(d4, LOW); 
      break;
    case 4: 
     digitalWrite(d1, LOW);
     digitalWrite(d2, LOW);
     digitalWrite(d3, LOW);
     digitalWrite(d4, HIGH); 
      break;
        default :
           digitalWrite(d1, LOW);
     digitalWrite(d2, LOW);
     digitalWrite(d3, LOW);
     digitalWrite(d4, LOW);
        break;
    }
}
void Num_0()
{
  digitalWrite(a, LOW);
  digitalWrite(b, LOW);
  digitalWrite(c, LOW);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, HIGH);
  digitalWrite(dp,HIGH);
}
void Num_1()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, LOW);
  digitalWrite(c, LOW);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp,HIGH);
}
void Num_2()
{
  digitalWrite(a, LOW);
  digitalWrite(b, LOW);
  digitalWrite(c, HIGH);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, HIGH);
  digitalWrite(g, LOW);
  digitalWrite(dp,HIGH);
}
void Num_3()
{
  digitalWrite(a, LOW);
  digitalWrite(b, LOW);
  digitalWrite(c, LOW);
  digitalWrite(d, LOW);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, LOW);
  digitalWrite(dp,HIGH);
}
void Num_4()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, LOW);
  digitalWrite(c, LOW);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp,HIGH);
}
void Num_5()
{
  digitalWrite(a, LOW);
  digitalWrite(b, HIGH);
  digitalWrite(c, LOW);
  digitalWrite(d, LOW);
  digitalWrite(e, HIGH);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp,HIGH);
}
void Num_6()
{
  digitalWrite(a, LOW);
  digitalWrite(b, HIGH);
  digitalWrite(c, LOW);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp,HIGH);
}
void Num_7()
{
  digitalWrite(a, LOW);
  digitalWrite(b, LOW);
  digitalWrite(c, LOW);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp,HIGH);
}
void Num_8()
{
  digitalWrite(a, LOW);
  digitalWrite(b, LOW);
  digitalWrite(c, LOW);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp,HIGH);
}
void Num_9()
{
  digitalWrite(a, LOW);
  digitalWrite(b, LOW);
  digitalWrite(c, LOW);
  digitalWrite(d, LOW);
  digitalWrite(e, HIGH);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp,HIGH);
}
void Clear()  //清屏
{
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp,HIGH);
}
void pickNumber(unsigned char n)//選數
{
  switch(n)
  {
   case 0:Num_0();
   break;
   case 1:Num_1();
   break;
   case 2:Num_2();
   break;
   case 3:Num_3();
   break;
   case 4:Num_4();
   break;
   case 5:Num_5();
   break;
   case 6:Num_6();
   break;
   case 7:Num_7();
   break;
   case 8:Num_8();
   break;
   case 9:Num_9();
   break;
   default:Clear();
   break; 
  }
}
void Display(unsigned char x, unsigned char Number)//顯示x為座標，Number為數字
{
  WeiXuan(x);
  pickNumber(Number);
  delay(500); //時間不能太長，要不ROS系統不穩定。
  Clear();
}
  

void messageCb(std_msgs::Empty &message)
{
      Display(1,1);

      Display(2,2);

      Display(3,3);

      Display(4,4);

}


ros::NodeHandle nh;
ros::Subscriber<std_msgs::Empty> sub("chatter",&messageCb); 


void setup(){
  
  nh.initNode();
  nh.subscribe(sub);
  pinMode(d1, OUTPUT);
  pinMode(d2, OUTPUT);
  pinMode(d3, OUTPUT);
  pinMode(d4, OUTPUT);
  pinMode(a, OUTPUT);
  pinMode(b, OUTPUT);
  pinMode(c, OUTPUT);
  pinMode(d, OUTPUT);
  pinMode(e, OUTPUT);
  pinMode(f, OUTPUT);
  pinMode(g, OUTPUT);
  pinMode(dp, OUTPUT);

}
  
void loop(){
  nh.spinOnce();
  delay(1000);
}
 

2.1 程式下載和執行

首先：roscore

其次：rosrun rosserial_python serial_node.py /dev/ttyACM0

/dev/ttyACM0  這個是自己的埠號

最後：rostopic pub -1 /buzzer_msgs/Int8 1

來張圖片：