1个LED的亮度自动控制

 1 int bright_number = 0;   //此变量用来表示LED的亮度
 2 int bright_gap = 5;      //此变量用来表亮度变化的增减量
 3 int LED_pin = 9;         //LED引脚，须用模拟口
 4 
 5 void setup()  
 6 { 
 7   pinMode(LED_pin, OUTPUT);     // 设置LED引脚为输出模式:
 8 } 
 9 
10 void loop() 
11 { 
12   analogWrite(LED_pin, bright_number);    //亮度写出
13   delay(1000);    //延时1000毫秒 
14   bright_number = bright_number + bright_gap;    //改变亮度
15   if (bright_number == 0 || bright_number == 255) 
16   {
17     bright_gap = - bright_gap ;  //逐渐变亮与逐渐变暗之间切换
18   }     
19  delay(2000);   //延时2000毫秒 
20 }