Lesson 99: Real-Time Cloick DS3231 to build LCD and LED Clock

Please select other codes for this lecture from the links below.

Related or required files and link to this lesson

Part 13: Clock and Timers

This code is part of a lesson on building LED clock Arduino and DS3231 RTC clock module. We are using HT16K33 4 digit LED display to make this clock. This is code 99-4. Basic HT16K33 clock.

00:00 Introduction
04:11 DS3231 Datasheet
05:07 DS3231 Wiring
06:38 Simple DS3231 Clock code and library
10:05 DS3231 Code using Alarm
14:07 Running DS3231 Clock code demonstration
17:49 Alarm Buzzer and LED wiring for DS3231, code and demo
22:21 LCD Clock using DS3231
23:57 LCD Clock Code for Arduino
28:43 Building Unlimited Alarm using DS3231 clock module
29:38 Unlimited alarm wiring diagram
31:29 DS3231 using Alarm with relay and AC bulb wiring
31:59 DS3231 Unlimited Alarm Arduino code
34:38 Demonstration of Unlimited Alarm with reset push button
35:40 LED Clock using DS3231 and HT16K33
38:45 LED Clock code explained
50:38 LED Clock Demonstration and settings


 /*
 * Lesson 99
 * file: DS3231_HT16K33_clock_display
 * Digital clock using DS3231 Real Time clock module and Arduino
 * Displays time on 4 digits seven segment dispaly HT16K33
 * Used DW3231 library and HT16K33 library below
 * watch video instruction:
 * 
 * video instruction  * https://youtu.be/LEQfzmO9Wm0
 *  * This code is part of Arduino Step by Step Course which starts here:  https://youtu.be/-6qSrDUA5a8
 *  
 * Written by Ahmad Shamshiri on Feb 07, 2021 in Ajax, Ontario, Canada
 * www.Robojax.com
 * 
  * 
 * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.* 
 * This code has been download from Robojax.com
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
  
  DS3231: Real-Time Clock. Simple example
  Read more: www.jarzebski.pl/arduino/komponenty/zegar-czasu-rzeczywistego-rtc-ds3231.html
  GIT: https://github.com/jarzebski/Arduino-DS3231
  Web: http://www.jarzebski.pl
  (c) 2014 by Korneliusz Jarzebski

  HT16k33 library
//  AUTHOR: Rob Tillaart
// VERSION: 0.1.0
// PURPOSE: demo
//     URL: http://www.adafruit.com/products/1002
//     URL: https://github.com/RobTillaart/HT16K33
  
*/

#include <Wire.h>
#include <DS3231.h>

DS3231 clock;
RTCDateTime dt;

#include "HT16K33.h"
HT16K33  seg(0x70);//initialize the display with 0x70 I2C address

//watch video for settings details and demo https://youtu.be/XGsT-0P0gMU
bool showSecond = true;//show or hide seconds. set to false to not show
unsigned int secondDisplayEvery=5000;//show seconds every 10 seconds
unsigned int secondBlinkCount=6;//show 3 blinks of second 
unsigned int secondDisplayDuration =20000;//for how long seconds should be shown (in milliseonds)
bool showLeadingZero =true;
bool showSecondNoBlink=true;//just count senconds no blink



unsigned long rememberTime = millis();


void showSeconds1();
void showSeconds2();
void setup()
{
  Serial.begin(9600);

  // Initialize DS3231
  Serial.println("Robojax Digitla Clock");
  Serial.println("using DS3231 and HT16K33");  
  clock.begin();
  seg.begin();
  Wire.setClock(100000);

  seg.displayOn();

  seg.setDigits(4);
  seg.displayTest(1); 
   
  seg.displayOff(); 
  delay(50);
  seg.displayOn();  
  seg.brightness(10);//set brightness from 1-15     
  // Set sketch compiling time
  clock.setDateTime(__DATE__, __TIME__);
  
  // Manual (YYYY, MM, DD, HH, II, SS
   //clock.setDateTime(2021, 4, 13, 8, 01, 00);  
}

void loop()
{
  (showLeadingZero)? seg.setDigits(4) : seg.setDigits(3);

  //watch video for details
  dt = clock.getDateTime();
 
  printTime();//print time on serial monitor
  seg.displayTime(dt.hour,dt.minute);
  seg.displayColon(1);     
  delay(500);
  seg.displayColon(0);  
  delay(500); 

  (showSecondNoBlink)? showSeconds2() : showSeconds1();  
 
}//



/*
 * 
 * @brief shows seconds on HT16K33 display
 * with blinking
 * @param none
 * @return no return value
 * written Feb 06, 2021 by Ahmad Shamshiri
 * www.robojax.com
 */
void showSeconds1()
{
  int count = secondBlinkCount;
  if(showSecond){
      if(millis() - rememberTime   > secondDisplayEvery)
      {
          while(count>=0)
          {
            dt = clock.getDateTime();         
            count -=1;      
            seg.setDigits(2);    
            seg.displayInt(dt.second);     
            delay(500);
            seg.displayOff();  
            delay(500);  
            seg.displayOn();
            rememberTime = millis()  ;  
          }// while end    
      }//if
  }//if showSecond is true
}//showSecond() end

/*
 * 
 * @brief shows seconds on HT16K33 display
 * without blinking. 
 * @param none
 * @return no return value
 * written Feb 06, 2021 by Ahmad Shamshiri
 * www.robojax.com
 */
void showSeconds2()
{
  int count = secondDisplayDuration;

  if(showSecond){
      if(millis() - rememberTime   > secondDisplayEvery)
      {
          while(count>=0)
          {        
            dt = clock.getDateTime();         
            count -=50;      
            seg.setDigits(2);    
            seg.displayInt(dt.second);     
            delay(50);
            rememberTime = millis()  ;  
          }// while end    
      }//if
  }//if showSecond is true
}//showSeconds2() end

/*
 * 
 * @brief prints time on serial monitor
 * @param none
 * @return no return value
 * written Feb 06, 2021 by Ahmad Shamshiri
 * www.robojax.com
 */
void printTime()
{
  Serial.print("Raw data: ");
  Serial.print(dt.year);   Serial.print("-");
  Serial.print(dt.month);  Serial.print("-");
  Serial.print(dt.day);    Serial.print(" ");
  Serial.print(dt.hour);   Serial.print(":");
  Serial.print(dt.minute); Serial.print(":");
  Serial.print(dt.second); Serial.println("");
}//printTime() end