Arduino Based CountDown Timer

Requirements:
Software:

1.ArduinoIDE    download:https://www.arduino.cc/en/Main/Software

2.LiquidCrystal.h library download: https://github.com/arduino/Arduino/tree/master/libraries/LiquidCrystal

3.LCDKeypad.h  library download: https://www.dfrobot.com/wiki/index.php/Arduino_LCD_KeyPad_Shield_(SKU:_DFR0009)

Hardware:

1.Arduino Uno     

2.LCD Keypad      


Cirduit Diagrams:

Arduino Code:

#include <LiquidCrystal.h>
#include "LCDKeypad.h"

#define HOURS 1
#define MINUTES 2
#define SECONDS 3// The LCD screen

LCDKeypad lcd;

unsigned int hours = 0;
unsigned int minutes = 0;
unsigned int seconds = 0;
unsigned int setting = 0;
unsigned int set = 0;

volatile byte pulseCount;

void setup() {

// Set up the LCD's number of columns and rows:

lcd.begin(16,2);
lcd.setCursor(5,0);
lcd.print("LEETs");
lcd.setCursor(4,1);
lcd.print("academy");
delay(2000);
lcd.clear();
lcd.setCursor(0,0);
lcd.print("Coundown Timer");
lcd.setCursor(0,1);
lcd.print("Hours =");
pulseCount = 0;

}

void loop() {

if(set == 1)
stepDown();
// Print the time on the LCD
printTime();
// Listen for buttons for 1 second

buttonListen();

}

//-----------------TIMER METHODS------------

//-----------------BUTTONS-----------------------

void buttonListen() {

// Read the buttons five times in a second
for (int i = 0; i < 5; i++) {
// Read the buttons value
int button = lcd.button();
switch (button) {
// Right button was pushed

case KEYPAD_RIGHT:
setting++;
break;

// Left button was pushed
case KEYPAD_LEFT:
setting--;
break;

// Up button was pushed
case KEYPAD_UP:
{

set = 0;
switch (setting) {
case HOURS:
hours++;
break;
case MINUTES:
minutes++;
break;
case SECONDS:
seconds++;

}

}

break;

// Down button was pushed
case KEYPAD_DOWN:{
set = 0;
switch (setting) {

case HOURS:
hours--;
if (hours == -1) hours = 23;
break;
case MINUTES:
minutes--;
if (minutes == -1) minutes = 59;
break;
case SECONDS:
seconds--;
if (seconds == -1) seconds = 59;

}

}
break;
case KEYPAD_SELECT:
{
set = 1;
}

}

setting %= 4;
printSetting();
hours%=24;
minutes %= 60;
seconds %= 60;

printTime();

// Wait one fifth of a second to complete
while(millis() % 200 != 0);

}
}

// Print the current setting
void printSetting() {

lcd.setCursor(0,1);

switch (setting) {

case HOURS:
lcd.print("Hours ");
break;
case MINUTES:
lcd.print("Minutes");
break;
case SECONDS:
lcd.print("Seconds");

}
}

//-----------------STEP DOWN------------------

//if (seconds > 0)
void stepDown()
{
if (seconds > 0)
{

seconds -= 1;
}
else if (minutes > 0)
{

seconds = 59;
minutes -= 1;
}

else if (hours > 0)
{
minutes = 59;
hours -= 1;
}

}

// Print the time on the LCD
void printTime() {

// Set the cursor at the begining of the second row
lcd.setCursor(8,1);
char time[17];
sprintf(time, "%02i:%02i:%02i", hours, minutes, seconds);
lcd.print(time);

}

void pulseCounter()
{
pulseCount++;
}