#include "RTClib.h"

int ledPin = 4;

RTC_DS1307 rtc;

void setup () {
  Serial.begin(57600);

  pinMode(ledPin, OUTPUT);

  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    abort();
  }

  if (! rtc.isrunning()) {
    Serial.println("RTC is NOT running, let's set the time!");
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }
}

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

  Serial.println(String("Текущее время: ") + time.timestamp(DateTime::TIMESTAMP_DATE) + String(" / ") + time.timestamp(DateTime::TIMESTAMP_TIME));

  static int lastMinute = -1;

  if (time.minute() != lastMinute) {
    lastMinute = time.minute();
    digitalWrite(ledPin, HIGH);
    delay(5000);
    digitalWrite(ledPin, LOW);
  }

  delay(1000);
}