Arduino Based Digital Alarm Clock

Published  July 8, 2016   50
S Saddam
Author
Arduino Alarm Clock Project

This Arduino based Real time clock is a digital clock to display real time using a RTC IC DS1307 which works on I2C protocol. Real time clock means it runs even after power failure. When power is reconnected, it displays the real time irespective to the time and duration it was in off state. In this Arduino alarm clock project we have used a 16x2 LCD module to display the time in - "hour, minute, seconds, date, month and year" format. An Alarm option is also added and we can set up the alarm time. Once alarm time it saved in internal EEPROM of arduino, it remains saved even after reset or electricity failure. Real time clocks are commonly used in our computers, houses, offices and electronics device for keeping them updated with real time.

I2C protocol is a method to connect two or more devices using two wires to a single system, and so this protocol is also called as two wire protocol. It can be used to communicate 127 devices to a single device or processor. Most of I2C devices run on100Khz frequency.

Steps for data writing master to slave (slave receiving mode)

  1. Sends START condition to slave.
  2. Sends slave address to slave.
  3. Send write bit (0) to slave.
  4. Received ACK bit from slave
  5. Sends words address to slave.
  6. Received ACK bit from slave
  7. Sends data to slave.
  8. Received ACK bit from slave.
  9. And last sends STOP condition to slave.

 

Steps for data reading from slave to master (slave transmitting mode)

  1. Sends START condition to slave.
  2. Sends slave address to slave.
  3. Send read bit (1) to slave.
  4. Received ACK bit from slave
  5. Received data from slave
  6. Received ACK bit from slave.
  7. Sends  STOP condition to slave.

To build this RTC DS1307 IC based digital clock, we have used here Arduino Pro Mini, but you can also use any other Arduino model such as Arduino Uno or Arduino Nano. Along with the Arduino board, DS1307 RTC IC, we have used 16x2 LCD module to display the time and date, a crystal osciallator, 7805 voltage regulator, a buzzer and few transistors and resistors.

 

Circuit Diagram and Description

Arduino Based Alarm Clock Circuit Diagram

In this Arduino based digital clock circuit, we have used three major components which are IC DS1307, Arduino Pro Mini Board and 16x2 LCD module.  

Here arduino is used for reading time from ds1307 and display it on 16x2 LCD. DS1307 sends time/date using 2 lines to arduino. A buzzer is also used for alarm indication, which beeps when alarm is activated. A block diagram is shown below to understand the working of this Real Time Clock.

Arduino based Alarm Clock Project Block Diagram

As you can see in the circuit diagram, DS1307 chip pin SDA and SCL are connected to arduino pins SDA and SCL with pull up resistor that holds default value HIGH at data and clock lines. 32.768KHz crystal oscillator is connected with DS1307 chip for generating exact 1 second delay, and a 3 volt battery is also connected to pin 3rd (BAT) of DS1307 which keeps time running after electricity failure. 16x2 LCD is connected with arduino in 4-bit mode. Control pin RS, RW and En are directly connected to arduino pin 2, GND and 3. And data pin D0-D7 is connected to 4, 5, 6, 7 of arduino. A buzzer is connected with arduino pin number 13 through a NPN BC547 transistor having a 1 k resistor at its base.

 

Three buttons namely set, INC and Next are used for setting alarm to pin 12, 11 and 10 of arduino in active low mode. When we press set, alarm set mode activates and now we need to set alarm by using INC button and Next button is used for moving to digit. The complete breadboard setup of this real time clock with alarm is shown in below image. You can also check a detailed tutorial on digital alarm clock with AVR microcontroller.

Breadboard setup of arduino based alarm clock

 

Program Description

To program for this real time clock, we have used some libraries for extracting time/date from DS1307 and for displaying on LCD, which are given below:

library

And initialization of RTC, LCD and input output are performed in setup loop.

Initialize

Rest of things like reading time, setting alarm is performed in void loop section.

reading time

Code

/* ----- C Program for Arduino based Alarm Clock ---- */

#include <Wire.h>
#include<EEPROM.h>
#include <RTClib.h>
#include <LiquidCrystal.h>

LiquidCrystal lcd(3, 2, 4, 5, 6, 7); 
RTC_DS1307 RTC;
int temp,inc,hours1,minut,add=11;

int next=10;    
int INC=11;
int set_mad=12;

#define buzzer 13

int HOUR,MINUT,SECOND;

 
void setup()
{
 Wire.begin();
 RTC.begin();
 lcd.begin(16,2);
 pinMode(INC, INPUT);
 pinMode(next, INPUT);
 pinMode(set_mad, INPUT);
 pinMode(buzzer, OUTPUT);
 digitalWrite(next, HIGH);
 digitalWrite(set_mad, HIGH);
 digitalWrite(INC, HIGH);
 
   lcd.setCursor(0,0);
   lcd.print("Real Time Clock");
   lcd.setCursor(0,1);
   lcd.print("Circuit Digest ");
    delay(2000);
    
 if(!RTC.isrunning())
 {
 RTC.adjust(DateTime(__DATE__,__TIME__));
 }
}
 
void loop()
{
   int temp=0,val=1,temp4;
   DateTime now = RTC.now();
   if(digitalRead(set_mad) == 0)      //set Alarm time
   { 
     lcd.setCursor(0,0);
     lcd.print("  Set Alarm  ");
    delay(2000);
    defualt();
    time();
    delay(1000);
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("  Alarm time ");
    lcd.setCursor(0,1);
    lcd.print(" has been set  ");
    delay(2000);
 }
 lcd.clear();
 lcd.setCursor(0,0);
 lcd.print("Time:");
 lcd.setCursor(6,0);
 lcd.print(HOUR=now.hour(),DEC); 
 lcd.print(":");
 lcd.print(MINUT=now.minute(),DEC);
 lcd.print(":");
 lcd.print(SECOND=now.second(),DEC);
 lcd.setCursor(0,1);
 lcd.print("Date: ");
 lcd.print(now.day(),DEC);
 lcd.print("/");
 lcd.print(now.month(),DEC);
 lcd.print("/");
 lcd.print(now.year(),DEC);
 match();
 delay(200);
}

void defualt()
{
  lcd.setCursor(0,1);
  lcd.print(HOUR);
  lcd.print(":");
  lcd.print(MINUT);
  lcd.print(":");
  lcd.print(SECOND);
}

/*Function to set alarm time and feed time into Internal eeprom*/

void time()                             
{
  int temp=1,minuts=0,hours=0,seconds=0;
    while(temp==1)
    {
     if(digitalRead(INC)==0)
     {
      HOUR++;
      if(HOUR==24)
      {
       HOUR=0;
      }
      while(digitalRead(INC)==0);
     }
     lcd.clear();
      lcd.setCursor(0,0);
    lcd.print("Set Alarm Time ");
   //lcd.print(x); 
    lcd.setCursor(0,1);
    lcd.print(HOUR);
    lcd.print(":");
    lcd.print(MINUT);
    lcd.print(":");
    lcd.print(SECOND);
    delay(100);
    if(digitalRead(next)==0)
    {
      hours1=HOUR;
      EEPROM.write(add++,hours1);
     temp=2;
     while(digitalRead(next)==0);
    }
    }
    
    while(temp==2)
    {
     if(digitalRead(INC)==0)
     {
      MINUT++;
      if(MINUT==60)
      {MINUT=0;}
      while(digitalRead(INC)==0);
     }
     // lcd.clear();
    lcd.setCursor(0,1);
    lcd.print(HOUR);
    lcd.print(":");
    lcd.print(MINUT);
    lcd.print(":");
    lcd.print(SECOND);
    delay(100);
      if(digitalRead(next)==0)
      {
       minut=MINUT;
       EEPROM.write(add++, minut);
       temp=0;
       while(digitalRead(next)==0);
      }
    }
    delay(1000);
}

/* Function to chack medication time */

void match()
{
  int tem[17];
  for(int i=11;i<17;i++)
  {
    tem[i]=EEPROM.read(i);
  }
  if(HOUR == tem[11] && MINUT == tem[12]) 
  {
   beep();
   beep();
   beep();
   beep();
   lcd.clear();
   lcd.print("Wake Up........");
   lcd.setCursor(0,1);
   lcd.print("Wake Up.......");
   beep();
   beep();
   beep();
   beep();
  }

}

/* function to buzzer indication */

void beep()
{
   digitalWrite(buzzer,HIGH);
   delay(500);
   digitalWrite(buzzer, LOW);
   delay(500);
}

Video

Comments

Submitted by Marko on Sun, 01/10/2016 - 01:28

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I am using Arduino uno and Arduino IDE 1.6.6 compailer, and when i compile the code he say that beep was not declared, any help?

Submitted by Muhammad Waqas on Mon, 04/11/2016 - 17:46

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I am using arduino uno. While compiling error appears like following.
{RTC_DS1307 does not name a type.}
Any help ....

Submitted by Diploma Student on Sun, 05/01/2016 - 09:41

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Is there any printed circuit board diagram that can you show ?
Can you explain what is arduino ?
Are this project cost really expensive ?
Can this project be done in 4 month or less than that ?

Submitted by Motty on Sun, 05/08/2016 - 16:55

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I am using Arduino: 1.6.8 (Windows 10), Board: "Arduino/Genuino Uno"

I put the same code but I got this error message:

Library can't use both 'src' and 'utility' folders. Double check C:\Program Files (x86)\Arduino\hardware\arduino\avr\libraries\Wire
Error compiling for board Arduino/Genuino Uno.

Plz help !!

Submitted by skiller on Thu, 08/18/2016 - 21:01

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i'm simualate on protues . i see after a period lcd be blink !
can you hepl me ? thank you very much ?

Submitted by mohamed on Wed, 08/24/2016 - 09:02

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thank you
when alarm on i must rest arduino to active another alarm

Submitted by shiva on Wed, 08/31/2016 - 21:24

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the date and time are wrong how should we set them peoperly?

Current Code already has provision to set the time to 'now' (DateTime now = RTC.now();). Further check this article for set the current time: arduino-info(dot)wikispaces(dot)com/DS1307_RealTime_Clock_Brick (replace dot with .)

Submitted by Atul Mishra on Wed, 10/12/2016 - 17:26

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I am using arduino uno. While compiling error appears like following.
{RTC_DS1307 does not name a type.}
plz do needful

For each include like the following, you will need to have installed the library. Google how to install arduino libraries.
#include <RTClib.h>

Submitted by Samrat Dutta on Fri, 10/21/2016 - 22:08

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Can i use arduino uno for making this project..please reply ..thank you..

Submitted by Arjun Oberai on Wed, 11/23/2016 - 11:24

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Right now the alarm works just once. To make it right, we have to just reset the value of the add to 11 int he void match().
In all just write this part (mentioned below) before the ending of the void match()
add = 11;
Thanks for the code Saddam!!

Submitted by Lan on Fri, 01/13/2017 - 20:29

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Hi we are conducting a Thesis Project "Real Time Clock alarm with buzzer using arduino device.
we are having a hard time for the set up but the video given was useful for us, we ask if You guys/admins can help us for the codes, tutorials for setting the kit and diagrams so our Thesis Project will function successfully, We are graduating students of Palawan State University, Puerto Princesa City, Palawan. we are hoping for the response Thank you. :)

Submitted by Gaurav on Sun, 02/05/2017 - 07:31

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Sir,plz gave list of equipment used in that project.which arduino can i use po mini or uno.

Submitted by santosh on Sun, 02/12/2017 - 12:39

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if(HOUR == tem[11] && MINUT == tem[12])
i want to know what is tem(11 )and tem( 12) stands for ?

Submitted by Ramesh on Fri, 03/17/2017 - 08:08

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Sir,i have loaded your code in to Arduino Uno,it compiled successfully without any error, but it not displaying anything in LCD. Only block comes n goes.
Pl tell me etc module required any previous string time before your code loading,if any pl tell me procedure to set RTc modules before loading your codes.
Thanks n pl reply,
Ramesh

I found the solution in code where liquid crystal(3,2,4,5,6,7) replace it by liquid crystal(2,3,4,5,6,7).

Submitted by hussnain on Fri, 04/14/2017 - 18:13

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Sir,i have loaded your code in to Arduino Uno,it compiled successfully without any error, but it not displaying anything in LCD. Only block comes and goes. but time is working good and alarm also working but on display blocks comes and goes and nothing displaying correctly.

What the error is plz tell me.
Thanks in advance.

I found the solution in code where liquid crystal(3,2,4,5,6,7) replace it by liquid crystal(2,3,4,5,6,7).

Submitted by iqu on Sun, 07/16/2017 - 11:37

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Dear sir, admin,
thank you for the project , i am a beginner and i have a request to make alarm in every 30 miniuts ,
please help me to do a write a code for it.

thanks and regards

Submitted by Joezzeth Mampusti on Tue, 01/16/2018 - 07:37

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How can i use 4x4 keypad instead of push button ?

Submitted by Abdul Muneeb on Fri, 04/13/2018 - 10:06

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R/Sir
How can I interface jammer with this circuit plz help me........

Submitted by Sebastian on Wed, 06/20/2018 - 07:02

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Hi!

I see that we can set multiple alarms given that once you set the alarms they go up to 9. What part of the code should i change to set only 1 alarm?