Simple Digital Clock Using Arduino Nano & DS1307

In this article I will show you a tutorial to make a digital clock using Arduino.. The Arduino board that I use is Arduino Nano V3, DS1307 as a time data provider, MAX7219 7 Segment as the watch display.

before entering the tutorial, I recommend that you are familiar with using Arduino devices and accessories. This will make it easier for you to follow the tutorial that I showed.

If you are not familiar with using Arduino boards, don't worry.

You can read this article to warm up:

Step 1: Required Components

these are the components we need to make a digital clock:

Arduino Nano V3
RTC DS1307
MAX7210 7Segment
Jumper Wire
USBmini
Project Board

Library Required :

Wire
LedControl
RTClib

Step 2: Assemble All Components

If all components have been obtained, Now it's time to assemble.

See the description below or see the picture above:

Arduino to RTC DS1307

GND => GND

+5V => VCC

A4 => SDA

A5 => SCL

Arduino to MAX7219

+5V => VCC

GND => GND

D12 => DIN

D11 => CLK

D10 => CS

After all components are installed, continue to the programming section.

Step 3: Programming

copy and paste this sketch into the sketch that you made. After that upload the program to the arduno board

#include 
#include "LedControl.h"
#include "RTClib.h"
RTC_DS1307 rtc;
LedControl lc=LedControl(12,11,10,1);
void setup() {
  Serial.begin(57600);
  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    while (1);
  }
  if (! rtc.isrunning()) {
    Serial.println("RTC is NOT running!");
    // 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));
  }
    lc.shutdown(0,false);
    lc.setIntensity(0,8);
    lc.clearDisplay(0);
}
void loop() {
  DateTime now = rtc.now();
  
  if(now.second() < 30 || now.second() > 40)
    {
      lc.setDigit(0,0,now.second()%10,false);
      lc.setDigit(0,1,now.second()/10,false);
      lc.setChar(0,2,'-',false);
      lc.setDigit(0,3,now.minute()%10,false);
      lc.setDigit(0,4,now.minute()/10,false);
      lc.setChar(0,5,'-',false);
      lc.setDigit(0,6,now.hour()%10,false);
      lc.setDigit(0,7,now.hour()/10,false);
  
    }
  if (now.second() == 30 || now.second() == 40) 
    {
      lc.clearDisplay(0);
    }
  if(now.second() >= 31 && now.second() < 40)
    {
      lc.setDigit(0,6,now.day()%10,true);
      lc.setDigit(0,7,now.day()/10,false);
      lc.setDigit(0,4,now.month()%10,true);
      lc.setDigit(0,5,now.month()/10,false);
      lc.setDigit(0,0,(now.year()%1000)%10,false);
      lc.setDigit(0,1,(now.year()%1000)/10,false);
      lc.setDigit(0,2,(now.year()%1000)/100,false);
      lc.setDigit(0,3,now.year()/1000,false);  
    }
}