int carRed = 12; //设置汽车灯
int carYellow = 11;
int carGreen = 10;
int button = 9; //按钮引脚
int pedRed = 8; //设置行人灯
int pedGreen = 7;
int crossTime = 5000;//允许行人通过的时间
unsigned long changeTime;//按钮按下后的时间

void setup() {
  //所有LED设置为输出模式
  pinMode(carRed, OUTPUT);
  pinMode(carYellow, OUTPUT);
  pinMode(carGreen, OUTPUT);
  pinMode(pedRed, OUTPUT);
  pinMode(pedGreen, OUTPUT);
  pinMode(button, INPUT); //按钮设置为输入模式
  digitalWrite(carGreen, HIGH); //开始时，汽车灯绿灯
  digitalWrite(pedRed, HIGH);  //行人灯为红灯
}

void loop() {
  int state = digitalRead(button);
  //检测按钮是否被按下，并且是否距上次按下后有5秒的等待时间
  if (state == HIGH && (millis() - changeTime) > 5000) {
    //调用变灯函数
    changeLights();
  }
}

void changeLights() {
    digitalWrite(carGreen, LOW);//汽车绿灯灭
    digitalWrite(carYellow, HIGH);//汽车黄灯亮
    delay(2000);//等待2秒

    digitalWrite(carYellow, LOW);//汽车黄灯灭
    digitalWrite(carRed, HIGH);//汽车红灯亮
    delay(1000);//为安全考虑等待1秒

    digitalWrite(pedRed, LOW);//行人红灯灭
    digitalWrite(pedGreen, HIGH);//行人绿灯亮
    delay(crossTime); //等待一个通过时间
    //闪烁行人灯绿灯，提示可过马路时间快到
   for (int x = 0; x < 10; x++) {
    digitalWrite(pedGreen, HIGH);
    delay(250);
    digitalWrite(pedGreen, LOW);
    delay(250);
  }
    digitalWrite(pedRed, HIGH);//行人红灯亮
    delay(500);

    digitalWrite(carRed, LOW);//汽车红灯灭
    digitalWrite(carYellow, HIGH);//汽车黄灯亮
    delay(1000);

    digitalWrite(carYellow, LOW);//汽车黄灯灭
    digitalWrite(carGreen, HIGH);//汽车绿灯亮

    changeTime = millis(); //记录自上一次灯变化的时间
    //返回到主函数循环中
}