1. https://blog.csdn.net/hunhun1122/article/details/70254606
2. http://www.51hei.com/arduino/3924.html
// initialize digital pin LED_BUILTIN as an output.
byte ledPin[ ] = {2, 3, 4, 5, 7, 8, 9, 10, 11}; //以LED引脚创建数组
int ledDelay(250); //变换灯之间的延时，你爱多少写多少（毫秒）
int dir = 1;
int currentLED = 0;
unsigned long changeTime;
void setup() {
for (int x=0; x<9; x++) //设置所有引脚为输出模式
{
pinMode(ledPin[x], OUTPUT);
}
changeTime = millis();
}
void loop()
{
if((millis() - changeTime) > ledDelay) //如果过了ledDelay毫秒，执行以下程序
{
changeLED();
changeTime = millis();
}
}
void changeLED() {
for (int x=0; x<9; x++) { //关闭所有灯
digitalWrite(ledPin[x], HIGH);
}
digitalWrite(ledPin[currentLED], LOW); //开一个灯
currentLED+=dir;
if (currentLED == 8) {dir = -1;}
if (currentLED == 0) {dir = 1;} //让灯轮流亮，到底换方向
}
