Ref Link::: Arduino Alarm

https://www.picmicrolab.com/lcd-digital-alarm-cloc...

Timers were used in many applications in our day to day life.One can see the timers in washing machines,micro ovens etc. These devices uses timer to switch the loads for particular amount of time.Traditionally, various loads would have been manually controlled, i.e., the operator would turn ON the loads and after desired conditions met, the loads again would have been turned off by the operator.

Here i am going to explain about Arduino Relay Timer, which doesn't require any External Real Time Clock module like DS1307.

Step 1: Circuit Explanation

Components

Arduino Board
LCD
Push buttons
Relay

Working
Initially when the circuit is switched LCD will display ” adjustable timer By Technical Hub”.after 2 secs the lcd will again shows the

Count 0:00:00

set to 0:00:00

Press the switch /push button (select button / connected to arduino pin 11)
Now using the two buttons(mins and hours (connected to arduino pin 8,9 resp..)) set the timer.Button connected to 8th pin is used to set the timer in minutes and button connected to 9th pin is used to set the timer in hours.
Set the time by pressing these buttons.When each button is pressed , time is incremented every time.
Now click on start button to switch the load.
When the count time == set to time load will be switched off automatically.
To set the timer next time click the reset button on the arduino and set the timer again.

Step 2: Code

you can download it from here:

https://drive.google.com/open?id=15DpFyfoZkwJoXggZ...

You can copy and paste the following code

#include <LiquidCrystal.h>
LiquidCrystal lcd(7,6,5,4,3,2);

int TimeHours10s =  0;
int TimeHours1s =  0;
int TimeMinutes10s =  0;
int TimeMinutes1s =  0;
int TimeSeconds10s =  0;
int TimeSeconds1s =  0;
int AlarmHours10s =  0;
int AlarmHours1s =  0;
int AlarmMinutes10s =  0;
int AlarmMinutes1s =  0;
int AlarmSeconds10s =  0;
int AlarmSeconds1s =  0;

int t=0;
int l=0;
int Select = 11;
int start = 10;
int Min = 8;
int Hour = 9;
int Buzzer =12;

void setup() 
{
  // initialize I/O pins.
  
  pinMode(Select,INPUT);  //
  pinMode(start, INPUT);  //
  pinMode(Hour, INPUT);  //
  pinMode(Min, INPUT);  //
  pinMode(Buzzer, OUTPUT);  //
  
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  lcd.print("Adjustable Timer"); 
  lcd.setCursor(0,1);
  lcd.print("By Tech garage");
  delay(2000);
  lcd.clear();
}

void loop() 
{
  
//CalculateTime();  
ShowTime();
ShowAlarm();
delay(500);
CompareAlarmTime();
//-------------------------------------setting up Alarm Value------------

if (digitalRead(Select)== HIGH)
{
  t=1;
  }
if(t==1 && digitalRead(Min)== HIGH)
{
  AlarmMinutes1s++;
  delay(500);
  CalculateAlarm();
}
if(t==1 && digitalRead(Hour)== HIGH)
{
  AlarmHours1s++;
  delay(500);
  CalculateAlarm();
}
//----------------------------------------------------------------

if(digitalRead(start)== HIGH)
{
  l=1;

 }
  if(l==1)
  {   CalculateTime();
  }
delay(500);
}

void ShowTime()
  {
  //--------------------------------------------
  // Turn on the display
  lcd.display();
  lcd.setCursor(0, 0); // top left
  lcd.print("Count  ");//
  if(TimeHours10s == 0)
  lcd.print(" ");//
  else
  lcd.print(TimeHours10s);//
  lcd.print(TimeHours1s);//
  lcd.print(":");//
  lcd.print(TimeMinutes10s);//
  lcd.print(TimeMinutes1s);//
  lcd.print(":");//
  lcd.print(TimeSeconds10s);//
  lcd.print(TimeSeconds1s);//
  lcd.setCursor(0, 0); // top left
  }

void ShowAlarm()
  {
  //--------------------------------------------
  // Turn on the display
  //lcd.display();
  lcd.setCursor(0, 1); // bottom left
  lcd.print("set to ");//
  if(AlarmHours10s == 0)
  lcd.print(" ");//
  else
  lcd.print(AlarmHours10s);//
  lcd.print(AlarmHours1s);//
  lcd.print(":");//
  lcd.print(AlarmMinutes10s);//
  lcd.print(AlarmMinutes1s);//
  lcd.print(":");//
  lcd.print(AlarmSeconds10s);//
  lcd.print(AlarmSeconds1s);//
  lcd.setCursor(0, 1); // bottom left
  }

void CalculateTime()
{
 TimeSeconds1s++;
  if(TimeSeconds1s == 10)
  {
  TimeSeconds1s = 0;
  TimeSeconds10s++;
  }
  if(TimeSeconds10s == 6)
  {
  TimeSeconds10s = 0;
  TimeSeconds1s = 0;
  TimeMinutes1s++;
  }
  if(TimeMinutes1s == 10)
  {
  TimeMinutes1s = 0;
  TimeSeconds10s = 0;
  TimeSeconds1s = 0;
  TimeMinutes10s++;
  }
  if(TimeMinutes10s == 6)
  {
  TimeMinutes10s = 0;
  TimeMinutes1s = 0;
  TimeSeconds10s = 0;
  TimeSeconds1s = 0;
  TimeHours1s++;
  }
  if(TimeHours1s == 10) 
  {
  TimeHours1s=0;
  TimeMinutes10s = 0;
  TimeMinutes1s = 0;
  TimeSeconds10s = 0;
  TimeSeconds1s = 0;
  TimeHours10s++;
  }
  if(TimeHours10s == 2 && TimeHours1s == 4) 
  {
  TimeHours10s=0; 
  TimeHours1s=0;
  TimeMinutes10s = 0;
  TimeMinutes1s = 0;
  TimeSeconds10s = 0;
  TimeSeconds1s = 0;
 
  } 
}

 void CalculateAlarm()
{
 //AlarmSeconds1s++;
  if(AlarmSeconds1s == 10)
  {
  AlarmSeconds1s = 0;
  AlarmSeconds10s++;
  }
  if(AlarmSeconds10s == 6)
  {
  AlarmSeconds10s = 0;
  AlarmSeconds1s = 0;
  AlarmMinutes1s++;
  }
  if(AlarmMinutes1s == 10)
  {
  AlarmMinutes1s = 0;
  AlarmSeconds10s = 0;
  AlarmSeconds1s = 0;
  AlarmMinutes10s++;
  }
  if(AlarmMinutes10s == 6)
  {
  AlarmMinutes10s = 0;
  AlarmMinutes1s = 0;
  AlarmSeconds10s = 0;
  AlarmSeconds1s = 0;
  AlarmHours1s++;
  }
  if(AlarmHours1s == 10) 
  {
  AlarmHours1s=0;
  AlarmMinutes10s = 0;
  AlarmMinutes1s = 0;
  AlarmSeconds10s = 0;
  AlarmSeconds1s = 0;
  AlarmHours10s++;
  }
  if(AlarmHours10s == 2 && AlarmHours1s == 4) 
  {
  AlarmHours10s=0; 
  AlarmHours1s=0;
  AlarmMinutes10s = 0;
  AlarmMinutes1s = 0;
  AlarmSeconds10s = 0;
  AlarmSeconds1s = 0;
  } 
}
 void CompareAlarmTime()
 {
  if(TimeHours10s >= AlarmHours10s && TimeHours1s >= AlarmHours1s && TimeMinutes10s >= AlarmMinutes10s && TimeMinutes1s >= AlarmMinutes1s )
  {
   digitalWrite(Buzzer, LOW); 
   
  }
  else
  {digitalWrite(Buzzer, HIGH); 
    }
  
 }