#include "RTClib.h"

RTC_DS1307 rtc;

unsigned int lastMinute = 0;

void setup() {
  pinMode(8, OUTPUT);
  Serial.begin(115200);

  if (!rtc.begin()) {
    abort();
  }

  Serial.println("Введите дату в формате DD-MM-YYYY/HH-MM-SS или now:");
  while (!Serial.available()) {
    delay(10);
  }

  String input = Serial.readString();
  if (input.substring(0,3) == "now") {
    return;
  }
  int day = input.substring(0, 2).toInt();
  int month = input.substring(3, 5).toInt();
  int year = input.substring(6, 10).toInt();
  int hour = input.substring(11, 13).toInt();
  int minute = input.substring(14, 16).toInt();
  int second = input.substring(17, 19).toInt();

  rtc.adjust(DateTime(year, month, day, hour, minute, second));
}

void loop() {
  DateTime now = rtc.now();

  Serial.print(now.year(), DEC);
  Serial.print('/');
  Serial.print(now.month(), DEC);
  Serial.print('/');
  Serial.print(now.day(), DEC);
  Serial.print(' ');
  Serial.print(now.hour(), DEC);
  Serial.print(':');
  Serial.print(now.minute(), DEC);
  Serial.print(':');
  Serial.print(now.second(), DEC);
  Serial.println();

  if (lastMinute != now.minute()) {
    lastMinute = now.minute();
    digitalWrite(8, HIGH);
  } else {
    digitalWrite(8, LOW);
  }

  delay(5000);
}