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 99-3 is part of a lesson 99 on building clock using Arduino and DS3231 RTC clock module. We are using it to turn on a buzzer and LED but you can use it with relay to turn ON/OFF AC load like bulb alarm or DC lodas. See video for full details.

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:  Arudino and DS3231 RTC module with alarm
 99-3
 * Full video details: https://youtu.be/LEQfzmO9Wm0
 * In this lesson we have the following codes:
 * -Basic DS3231 to display on serial monitor
 * -Using alarm feature of the DS3231 (this code)
 * -LCD Clock
 * -4 Digit LED Clock
 * -Unlimited Alarms using DS3231 with reset push button
 * 
 * 
 * This code is part of Arduino Step by Step Course which starts here:  https://youtu.be/-6qSrDUA5a8
 * 
 * for library of this code visit http://robojax.com/
 * 
If you found this tutorial helpful, please support me so I can continue creating 
content like this. Make a donation using PayPal by credit card https://bit.ly/donate-robojax
  
 * 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/>.

 
#include <Wire.h>
#include "RTClib.h"

#define alarmPin 2

const int alarm[]={2019,6,14,22,17,0};
const int waitTime =4000;


RTC_DS1307 rtc;


void setup () {
  pinMode(alarmPin,OUTPUT);//set pin 2 as output
 
  while (!Serial); // for Leonardo/Micro/Zero

  Serial.begin(9600);
  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(2019, 3, 3, 20, 0, 0));
  }
  //rtc.adjust(DateTime(2019, 3, 3, 20, 0, 0));
   //rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
}

void loop () {
    DateTime robojax = rtc.now();
    Serial.print("Alarm: ");
    for(int i=0;i<6;i++){
      Serial.print(alarm[i]);
      if(i !=5){
        Serial.print("-");
      }
    }
    Serial.println();
    Serial.print("Time:  ");
    Serial.print(robojax.year(), DEC);
    Serial.print("-");
    Serial.print(robojax.month(), DEC);
    Serial.print("-");
    Serial.print(robojax.day(), DEC);
    Serial.print("-");    
    Serial.print(robojax.hour(), DEC);
    Serial.print("-");
    Serial.print(robojax.minute(), DEC);
    Serial.print("-");
    Serial.print(robojax.second(), DEC);
    Serial.println();
 
   if(checkAlarm(robojax)){
    digitalWrite(alarmPin, HIGH);// 
    Serial.print("Alarm Triggered");
    delay(waitTime);
    //while (1);// wait for ever 
   }else{
    digitalWrite(alarmPin, LOW);//
   }
    Serial.println();
    delay(500);
}

/*
 * 
 * @brief returns true if alarm array matches the current time
 * @param timeNow, is the object for RTC clock
 * @return true if alarm values matches current time
 * Written by Ahmad Shamshiri for Robojax.com 
 * on Friday Jun 14th, 2019 at 20:28 in Ajax, Ontatio, Canada
 * 
 */

boolean checkAlarm(DateTime timeNow){

  if(
   alarm[0] ==timeNow.year()
   &&
   alarm[1] ==timeNow.month()
   &&
   alarm[2] ==timeNow.day()
   &&
   alarm[3] ==timeNow.hour()
   &&
   alarm[4] ==timeNow.minute()
   &&
   alarm[5] ==timeNow.second()
   ){
      return true;
   }else{
      return false;
     
   }
  
}//checkAlarm

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