Arduino：LED亮度漸變

所需硬體

1. Arduino開發闆
2. LED
3. 220歐電阻
4. 導線
5. 實驗電路闆

電路連接配接方式

将LED的陽極（較長的正極管腳）通過一個220歐電阻連接配接到開發闆的數字輸出9腳。将陰極（較短的負極管腳）直接連接配接到地。

代碼

int led = 9;           // the PWM pin the LED is attached to
int brightness = 0;    // how bright the LED is
int fadeAmount = 5;    // how many points to fade the LED by

// the setup routine runs once when you press reset:
void setup() {
  // declare pin 9 to be an output:
  pinMode(led, OUTPUT);
}

// the loop routine runs over and over again forever:
void loop() {
  // set the brightness of pin 9:
  analogWrite(led, brightness);

  // change the brightness for next time through the loop:
  brightness = brightness + fadeAmount;

  // reverse the direction of the fading at the ends of the fade:
  if (brightness == 0 || brightness == 255) {
    fadeAmount = -fadeAmount ;
  }
  // wait for 30 milliseconds to see the dimming effect
  delay(30);
}