int redPin = 9;
int greenPin = 10;
int bluePin = 11;

void setup() {
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);
}

void loop() {
  // Aumenta brillo rojo
  for (int i = 0; i <= 255; i++) {
    analogWrite(redPin, i);
    delay(10);
  }
  // Disminuye brillo rojo
  for (int i = 255; i >= 0; i--) {
    analogWrite(redPin, i);
    delay(10);
  }
}