Arduino Based Digital Clock With Alarm Using 1602 LCD

Hi guys in this instructables we will learn how to make a digital clock from arduino using LCD display and we can also set a alarm with as well.

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.

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 DS1307chip 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.

Please copy the following following code and upload it to the arduino. :


#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);
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);
}

So after uploading the code and connecting everything together and you will see the clock running in the LCD display and you can even set the alarm in it as i did it in images. So have fun making your alarm clock with your arduino.