#define LED 6

void setup() {
  pinMode(LED, OUTPUT);
  Serial.begin(9600);
}

void loop() {

  // เพิ่มความสว่าง LED
  for (int i = 0; i <= 255; i++) {
    analogWrite(LED, i);

    Serial.print("PWM = ");
    Serial.println(i);

    delay(100);
  }

  // ลดความสว่าง LED
  for (int i = 255; i >= 0; i--) {
    analogWrite(LED, i);

    Serial.print("PWM = ");
    Serial.println(i);

    delay(10);
  }
}