// Date and time functions using a DS3231 RTC connected via I2C and Wire lib
    #include <Wire.h>
    #include "RTClib.h"
    #include <TinyGPS++.h> //http://arduiniana.org/libraries/tinygpsplus/ Used for GPS parsing

    HardwareSerial uart(1);

    TinyGPSPlus gps;

    RTC_DS3231 rtc;

    int DOW, MONTH, DATE, YEAR, HOUR, MINUTE, SECOND;

    char daysOfTheWeek[7][12] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};

    void setup ()
    {

    #ifndef ESP8266
         while (!Serial); // for Leonardo/Micro/Zero
    #endif

         Serial.begin(9600);
         uart.begin(9600, SERIAL_8N1, 17, 16);

         delay(3000); // wait for console opening

         if (! rtc.begin())
         {
              Serial.println("Couldn't find RTC");
              while (1);
         }

         if (rtc.lostPower())
         {
              Serial.println("RTC lost power, lets set the time!");
              // following line sets the RTC to the date & time this sketch was compiled
              //rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
              // This line sets the RTC with an explicit date & time, for example to set
              // January 21, 2014 at 3am you would call:
              rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));
         }


    }

    void loop ()
    {

         // This sketch displays information every time a new sentence is correctly encoded.
         while (uart.available() > 0)
              if (gps.encode(uart.read()))
                   displayInfo();


         if (millis() > 5000 && gps.charsProcessed() < 10)
         {
              Serial.println(F("No GPS detected: check wiring."));
              while(true);
         }

         Now_Time();

         if((MINUTE % 5 == 0) && (SECOND == 0))  //Change update interval here...
         {
              RTC_UPDATE();

              delay(1000 * 10);

         }



    }

    void displayInfo()
    {

         Serial.print(F("Location: "));
         if (gps.location.isValid())
         {
              Serial.print(gps.location.lat(), 6);
              Serial.print(F(","));
              Serial.print(gps.location.lng(), 6);
         }
         else
         {
              Serial.print(F("INVALID"));
         }

         Serial.print(F("  Date/Time: "));
         if (gps.date.isValid())
         {
              Serial.print(gps.date.month());
              Serial.print(F("/"));
              Serial.print(gps.date.day());
              Serial.print(F("/"));
              Serial.print(gps.date.year());
         }
         else
         {
              Serial.print(F("INVALID"));
         }

         Serial.print(F(" "));
         if (gps.time.isValid())
         {
              if (gps.time.hour() < 10) Serial.print(F("0"));
              Serial.print(gps.time.hour());
              Serial.print(F(":"));
              if (gps.time.minute() < 10) Serial.print(F("0"));
              Serial.print(gps.time.minute());
              Serial.print(F(":"));
              if (gps.time.second() < 10) Serial.print(F("0"));
              Serial.print(gps.time.second());
              Serial.print(F("."));
              if (gps.time.centisecond() < 10) Serial.print(F("0"));
              Serial.print(gps.time.centisecond());
         }
         else
         {
              Serial.print(F("INVALID"));
         }

         Serial.println();


    }

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

         YEAR = now.year();
         MONTH = now.month();
         DATE = now.day();
         DOW = now.dayOfTheWeek();
         HOUR = now.hour();
         MINUTE = now.minute();
         SECOND = now.second();

    }

    void RTC_READ()
    {

         DateTime now = rtc.now();

         Serial.print("RTC Date/Time  ");
         Serial.println("");
         Serial.print(now.year(), DEC);
         Serial.print('/');
         Serial.print(now.month(), DEC);
         Serial.print('/');
         Serial.print(now.day(), DEC);
         Serial.print(" (");
         Serial.print(daysOfTheWeek[now.dayOfTheWeek()]);
         Serial.print(") ");
         Serial.print(now.hour(), DEC);
         Serial.print(':');
         Serial.print(now.minute(), DEC);
         Serial.print(':');
         Serial.print(now.second(), DEC);
         Serial.println();

    }

    void RTC_UPDATE()
    {

         RTC_READ();

         Serial.println("");
         Serial.print(F("GPS UTC Date/Time: "));

         struct tm  timeinfo;
         unsigned long int unixtime;

         timeinfo.tm_year =  gps.date.year() - 1900;
         timeinfo.tm_mon = gps.date.month() - 1;
         timeinfo.tm_mday =  gps.date.day();
         timeinfo.tm_hour =  gps.time.hour();
         timeinfo.tm_min =  gps.time.minute();
         timeinfo.tm_sec = gps.time.second();

         unixtime = mktime(&timeinfo);
         Serial.println("");
         printf("unixtime = %u\n", unixtime);

         rtc.adjust(DateTime(unixtime));
		 

         Serial.println("RTC updated");
         Serial.println("");

         RTC_READ();

    }