arduino常规课11--倒计时

1 数码管介绍

数码管

image.png

fritzing里面搜：segment

2.接线图

上面：
从左到右为：5,6,gnd,3,4
下面：
从左到右为：9,8，gnd，7，null

接线图

3.代码

让数码管从0到9依次亮一遍

int a=3,b=4,c=7,d=8,e=9,f=6,g=5;
void drawZero()
{
    digitalWrite(a,HIGH);
    digitalWrite(b,HIGH);  
    digitalWrite(c,HIGH);  
    digitalWrite(d,HIGH);  
    digitalWrite(e,HIGH);  
    digitalWrite(f,HIGH);    
}
void drawOne()
{
    digitalWrite(b,HIGH);
    digitalWrite(c,HIGH);  
}
void drawTwo()
{
    digitalWrite(a,HIGH);
    digitalWrite(b,HIGH);
    digitalWrite(g,HIGH);
    digitalWrite(d,HIGH);
    digitalWrite(e,HIGH);
}
void drawThree()
{
    digitalWrite(a,HIGH);
    digitalWrite(b,HIGH);
    digitalWrite(g,HIGH);
    digitalWrite(d,HIGH);
    digitalWrite(c,HIGH);  
}
void drawFour()
{
    digitalWrite(f,HIGH);
    digitalWrite(b,HIGH);
    digitalWrite(g,HIGH);  
    digitalWrite(c,HIGH);
}
void drawFive()
{
    digitalWrite(a,HIGH);
    digitalWrite(f,HIGH);
    digitalWrite(g,HIGH);
    digitalWrite(d,HIGH);
    digitalWrite(c,HIGH); 
}
void drawSix()
{
    digitalWrite(a,HIGH);
    digitalWrite(f,HIGH);
    digitalWrite(g,HIGH);
    digitalWrite(d,HIGH);
    digitalWrite(c,HIGH); 
    digitalWrite(e,HIGH); 
}
void drawSeven()
{
    digitalWrite(a,HIGH);
    digitalWrite(b,HIGH);
    digitalWrite(c,HIGH);
}
void drawEight()
{
    digitalWrite(a,HIGH);
    digitalWrite(f,HIGH);
    digitalWrite(g,HIGH);
    digitalWrite(d,HIGH);
    digitalWrite(c,HIGH); 
    digitalWrite(e,HIGH); 
    digitalWrite(b,HIGH);
}
void drawNine()
{
    digitalWrite(a,HIGH);
    digitalWrite(f,HIGH);
    digitalWrite(g,HIGH);
    digitalWrite(d,HIGH);
    digitalWrite(c,HIGH); 
    digitalWrite(b,HIGH);
}
void clear_()
{
    digitalWrite(a,LOW);  
    digitalWrite(b,LOW); 
    digitalWrite(c,LOW);  
    digitalWrite(d,LOW);  
    digitalWrite(e,LOW);  
    digitalWrite(f,LOW);  
    digitalWrite(g,LOW);  
}
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  for(int i=3;i<=9;i++) pinMode(i,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  drawZero();
  delay(200);
 clear_();

  drawOne();
  delay(200);
clear_();
  drawTwo();
  delay(200);
clear_();
  drawThree();
  delay(200);
clear_();
  drawFour();
  delay(200);
clear_();
  drawFive();
  delay(200);
clear_();
  drawSix();
  delay(200);
clear_();
  drawSeven();
  delay(200);
clear_();
  drawEight();
  delay(200);
clear_();
  drawNine();
  delay(200);
  clear_();
}

简化一下，用二维数组：

int a=3,b=4,c=7,d=8,e=9,f=6,g=5;
int draw[10][7]=
{
{a,b,c,d,e,f,-1}, //0
{b,c,-1,-1,-1,-1,-1}, //1
{a,b,g,d,e,-1,-1}, //2
{a,b,g,d,c,-1,-1}, //3
{f,b,g,c,-1,-1,-1}, //4
{a,f,g,d,c,-1,-1}, //5
{a,f,g,d,c,e,-1}, //6
{a,b,c,-1,-1,-1,-1}, //7
{a,b,c,d,e,f,g}, //8
{a,f,g,d,c,b,-1} //9
};
void clear_()
{
    for(int i=3;i<=9;i++) digitalWrite(LOW);
}
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  for(int i=3;i<=9;i++) pinMode(i,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  for(int i=0;i<10;i++)
  {
      for(int j=0;j<7;j++)
      {
          if(draw[i][j]==-1) break;
          digitalWrite(draw[i][j],HIGH);  
      }
      delay(200);
      clear_();  
  }
}

加一个按钮，让数字随按钮变化：
按钮管脚是2

int a=3,b=4,c=7,d=8,e=9,f=6,g=5;
int num=0;
int draw[10][7]=
{
{a,b,c,d,e,f,-1}, //0
{b,c,-1,-1,-1,-1,-1}, //1
{a,b,g,d,e,-1,-1}, //2
{a,b,g,d,c,-1,-1}, //3
{f,b,g,c,-1,-1,-1}, //4
{a,f,g,d,c,-1,-1}, //5
{a,f,g,d,c,e,-1}, //6
{a,b,c,-1,-1,-1,-1}, //7
{a,b,c,d,e,f,g}, //8
{a,f,g,d,c,b,-1} //9
};
void clear_()
{
   for(int i=3;i<=9;i++) digitalWrite(i,LOW);

}
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  for(int i=3;i<=9;i++) pinMode(i,OUTPUT);
  pinMode(2,INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
//  Serial.println(digitalRead(2));
  if(!digitalRead(2))
  {
    delay(100);
      while(!digitalRead(2));
      num=(num+1)%10;
      clear_(); 
    //  Serial.println(num);
  }
   for(int j=0;j<7;j++)
   {
          if(draw[num][j]==-1) break;
          digitalWrite(draw[num][j],HIGH);  
    }
  
}