// Define the PWM pin for controlling LED brightness
const int ledPin = 10;  // Choose any PWM-capable pin (e.g., pin 9)

void setup() {
  // Set the LED pin as an output
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // Increase LED brightness gradually from off to full brightness
  for (int brightness = 0; brightness <= 255; brightness++) {
    analogWrite(ledPin, brightness);
    delay(10);  // Adjust delay time for smoother transition
  }

  // Decrease LED brightness gradually from full brightness to off
  for (int brightness = 255; brightness >= 0; brightness--) {
    analogWrite(ledPin, brightness);
    delay(10);  // Adjust delay time for smoother transition
  }
}