// 定义3个LED引脚
const int ledPin1 = 2;
const int ledPin2 = 3;
const int ledPin3 = 4;

// 设置呼吸灯的最小和最大亮度
int minBrightness = 0;
int maxBrightness = 255;

// 设置呼吸灯的步长
int fadeStep = 5;
int a[5]={3,5,6,9,10};
void setup(){// 设置LED引脚为输出模式
pinMode(3, OUTPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
pinMode(9, OUTPUT);
pinMode(10, OUTPUT);
}

void loop(){int i=random(0,4);
fadeLED(a[i]);
fadeLED(a[i+1]);

}

// 控制单个LED灯的呼吸效果
void fadeLED(int pin) 
{
  int delayTime=random(1,20);//获取随机数2到5之间
// 逐渐增加亮度
for (int brightness = minBrightness; brightness <= maxBrightness; brightness += fadeStep) 
{
analogWrite(pin, brightness);
delay(delayTime);
}

// 逐渐减小亮度
for (int brightness = maxBrightness; brightness >= minBrightness; brightness -= fadeStep) 
{
analogWrite(pin, brightness);
delay(delayTime);
}
}