int duty_cycle_val = 0;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  // int LED_BUILTIN = 2;
  //pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  analogWrite(LED_BUILTIN, 0);
  delay(5000);
  analogWrite(LED_BUILTIN, 125);
  delay(5000);
  analogWrite(LED_BUILTIN, 255);
  delay(5000);
}