#include <Wire.h>
#include <RTClib.h>

RTC_DS1307 rtc;

const int ledPin = 13; 

void setup() {
  rtc.begin();

  if (!rtc.isrunning()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }

  pinMode(ledPin, OUTPUT);
}

void loop() {
  DateTime now = rtc.now();
  int currentHour = now.hour();
  int currentMinute = now.minute();

  if (
    (currentHour == 2 && currentMinute >= 40 && currentMinute <= 45) ||
    (currentHour == 21 && currentMinute >= 0 && currentMinute <= 5)
  ) {
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(ledPin, LOW);
  }
}