Arduino Digital Clock with Alarm Function

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Introduction

Published date: 7/2/2018

In this DIY guide I will show you how to make your own digital clock this alarm function. In this project I decided to make my own PCB that is based on Arduino UNO microcontroller - Atmega328p.
Bellow you will find the electronic schematic with PCB layout so you can easily produce it.

Let's get started.

What you will need - Hardware

For this project you will need:

You will also need a TTL to USB module or an Arduino UNO board for the programming procedure.

The circuit at EasyEDA, the free online circuit design platform

Enter here to see and make any changes to the above circuite.

EasyEDA is a free, zero- install, cloud-based EDA tool, designed to give electrical engineers, educators, engineering students and electronics hobbyists an Easier EDA Experience. It is easy to use circuit design, circuit simulator and PCB design that runs in your web browser.

The code

Connect your circuit with TTL to USB module with 5 cables to the programming header. The pins RX and TX must be cross-connected.

NOTE: If you are using the Arduino UNO board make sure to remove the ATmega328 IC from it first and connect the headers RX to RX and TX to TX pins of the board. The RS pin must be connected to Arduino UNO reset pin.

/*  Digital Clock with Alarm Function
 *  More info: http://www.ardumotive.com/
 *  Dev: Michalis Vasilakis Data: 19/11/2016 Ver: 1.0
 *  
 *  Display 16x2:         Setup:            Setup Alarm
 *  +----------------+  +----------------+ +----------------+ 
 *  |HH:MM:SS|* HH:MM|  |    >HH :>MM    | |   Set Alarm    |
 *  |DD/MM/YY|  ALARM|  |>DD />MM />YYYY | |   >HH :>MM     |
 *  +----------------+  +----------------+ +----------------+
 */

//Libraries
#include <Wire.h>
#include "RTClib.h"
#include <LiquidCrystal.h>
#include <EEPROM.h>

//Connections and constants 
LiquidCrystal lcd(8,7,6,5,4,3); //LCD
RTC_DS1307 rtc; //DS1307 i2c
char daysOfTheWeek[7][12] = {"Sunday","Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
const int btSet = A0;
const int btAdj = A1;
const int btAlarm = A2;
const int buzzer = 11;
const int shakeSensor = A3;
long interval = 300;  
int melody[] = { 600, 800, 1000,1200 };

//Variables
int DD,MM,YY,H,M,S,set_state, adjust_state, alarm_state,AH,AM, shake_state;
int shakeTimes=0;
int i =0;
int btnCount = 0;
String sDD;
String sMM;
String sYY;
String sH;
String sM;
String sS;
String aH="12";
String aM="00";
String alarm = "     ";
long previousMillis = 0;    

//Boolean flags
boolean setupScreen = false;
boolean alarmON=false;
boolean turnItOn = false;
   
void setup() {
  //Init RTC and LCD library items
  rtc.begin();
  lcd.begin(16,2);
  //Set outputs/inputs
  pinMode(btSet,INPUT_PULLUP);
  pinMode(btAdj,INPUT_PULLUP);
  pinMode(btAlarm, INPUT_PULLUP);
  pinMode(buzzer, OUTPUT);
  //Check if RTC has a valid time/date, if not set it to 00:00:00 01/01/2018.
  //This will run only at first time or if the coin battery is low.
  if (! rtc.isrunning()) {
    Serial.println("RTC is NOT running!");
    // This line sets the RTC with an explicit date & time, for example to set
    // January 1, 2018 at 00:00am you would call:
    rtc.adjust(DateTime(2018, 01, 01, 00, 00, 0)); 
  }
  delay(100);
  //Read alarm time from EEPROM memmory
  AH=EEPROM.read(0);
  AM=EEPROM.read(1);
  //Check if the numbers that you read are valid. (Hours:0-23 and Minutes: 0-59)
  if (AH>23){
    AH=0;
  }
  if (AM>59){
    AM=0;
  }
}

void loop() {
  readBtns();       //Read buttons 
  getTimeDate();    //Read time and date from RTC
  if (!setupScreen){
    lcdPrint();     //Normanlly print the current time/date/alarm to the LCD
    if (alarmON){
     callAlarm();   // and check the alarm if set on
    }
  }
  else{
    timeSetup();    //If button set is pressed then call the time setup function
  }
  
}

/*************** Functions ****************/
//Read buttons state
void readBtns(){
  set_state = digitalRead(btSet);
  adjust_state = digitalRead(btAdj);
  alarm_state = digitalRead(btAlarm);
  if(!setupScreen){
    if (alarm_state==LOW){
      if (alarmON){
        alarm="     ";
        alarmON=false;
      }
      else{
        alarm="ALARM";
        alarmON=true;
      }
      delay(500);
    }
  }
  if (set_state==LOW){
    if(btnCount<7){
      btnCount++;
      setupScreen = true;
        if(btnCount==1){
          lcd.clear();
          lcd.setCursor(0,0);
          lcd.print("------SET------");
          lcd.setCursor(0,1);
          lcd.print("-TIME and DATE-");
          delay(2000);
          lcd.clear();
        }
    } 
    else{
      lcd.clear();
      rtc.adjust(DateTime(YY, MM, DD, H, M, 0)); //Save time and date to RTC IC
      EEPROM.write(0, AH);  //Save the alarm hours to EEPROM 0
      EEPROM.write(1, AM);  //Save the alarm minuted to EEPROM 1
      lcd.print("Saving....");
      delay(2000);
      lcd.clear();
      setupScreen = false;
      btnCount=0;
    }
    delay(500);
  }
}

//Read time and date from rtc ic
void getTimeDate(){
  if (!setupScreen){
    DateTime now = rtc.now();
    DD = now.day();
    MM = now.month();
    YY = now.year();
    H = now.hour();
    M = now.minute();
    S = now.second();
  }
  //Make some fixes...
  if (DD<10){ sDD = '0' + String(DD); } else { sDD = DD; }
  if (MM<10){ sMM = '0' + String(MM); } else { sMM = MM; }
  sYY=YY-2000;
  if (H<10){ sH = '0' + String(H); } else { sH = H; }
  if (M<10){ sM = '0' + String(M); } else { sM = M; }
  if (S<10){ sS = '0' + String(S); } else { sS = S; }
  if (AH<10){ aH = '0' + String(AH); } else { aH = AH; }
  if (AM<10){ aM = '0' + String(AM); }  else { aM = AM; }
}
//Print values to the display
void lcdPrint(){
  String line1 = sH+":"+sM+":"+sS+" | "+aH+":"+aM;
  String line2 = sDD+"/"+sMM+"/"+sYY +" | "+alarm;
  lcd.setCursor(0,0); //First row
  lcd.print(line1);
  lcd.setCursor(0,1); //Second row
  lcd.print(line2);  
}

//Setup screen
void timeSetup(){
  int up_state = adjust_state;
  int down_state = alarm_state;
  if(btnCount<=5){
    if (btnCount==1){         //Set Hour
      lcd.setCursor(4,0);
      lcd.print(">"); 
      if (up_state == LOW){   //Up button +
        if (H<23){
          H++;
        }
        else {
          H=0;
        }
        delay(350);
      }
      if (down_state == LOW){ //Down button -
        if (H>0){
          H--;
        }
        else {
          H=23;
        }
        delay(350);
      }
    }
    else if (btnCount==2){      //Set  Minutes
      lcd.setCursor(4,0);
      lcd.print(" ");
      lcd.setCursor(9,0);
      lcd.print(">");
      if (up_state == LOW){
        if (M<59){
          M++;
        }
        else {
          M=0;
        }
        delay(350);
      }
      if (down_state == LOW){
        if (M>0){
          M--;
        }
        else {
          M=59;
        }
        delay(350);
      }
    }
    else if (btnCount==3){      //Set Day
      lcd.setCursor(9,0);
      lcd.print(" ");
      lcd.setCursor(0,1);
      lcd.print(">");
      if (up_state == LOW){
        if (DD<31){
          DD++;
        }
        else {
          DD=1;
        }
        delay(350);
      }
      if (down_state == LOW){
        if (DD>1){
          DD--;
        }
        else {
          DD=31;
        }
        delay(350);
      }
    }
    else if (btnCount==4){      //Set Month
      lcd.setCursor(0,1);
      lcd.print(" ");
      lcd.setCursor(5,1);
      lcd.print(">");
      if (up_state == LOW){
        if (MM<12){
          MM++;
        }
        else {
          MM=1;
        }
        delay(350);
      }
      if (down_state == LOW){
        if (MM>1){
          MM--;
        }
        else {
          MM=12;
        }
        delay(350);
      }
    }
    else if (btnCount==5){      //Set Year
      lcd.setCursor(5,1);
      lcd.print(" ");
      lcd.setCursor(10,1);
      lcd.print(">");
      if (up_state == LOW){
        if (YY<2999){
          YY++;
        }
        else {
          YY=2000;
        }
        delay(350);
      }
      if (down_state == LOW){
        if (YY>2018){
          YY--;
        }
        else {
          YY=2999;
        }
        delay(350);
      }
    }
    lcd.setCursor(5,0);
    lcd.print(sH);
    lcd.setCursor(8,0);
    lcd.print(":");
    lcd.setCursor(10,0);
    lcd.print(sM);
    lcd.setCursor(1,1);
    lcd.print(sDD);
    lcd.setCursor(4,1);
    lcd.print("/");
    lcd.setCursor(6,1);
    lcd.print(sMM);
    lcd.setCursor(9,1);
    lcd.print("/");
    lcd.setCursor(11,1);
    lcd.print(sYY);
  }
  else{
    setAlarmTime();
  }
}

//Set alarm time
void setAlarmTime(){
  int up_state = adjust_state;
  int down_state = alarm_state;
  String line2;
  lcd.setCursor(0,0);
  lcd.print("SET  ALARM TIME");
  if (btnCount==6){             //Set alarm Hour
    if (up_state == LOW){
      if (AH<23){
        AH++;
      }
      else {
        AH=0;
      }
      delay(350);
    }
    if (down_state == LOW){
      if (AH>0){
        AH--;
      }
      else {
        AH=23;
      }
      delay(350);
    }
    line2 = "    >"+aH+" : "+aM+"    ";
  }
  else if (btnCount==7){        //Set alarm Minutes
    if (up_state == LOW){
      if (AM<59){
        AM++;
      }
      else {
        AM=0;
      }
      delay(350);
    }
    if (down_state == LOW){
      if (AM>0){
        AM--;
      }
      else {
        AM=59;
      }
      delay(350);
    }
    line2 = "     "+aH+" :>"+aM+"    ";    
  }
  lcd.setCursor(0,1);
  lcd.print(line2);
}

void callAlarm(){
  if (aM==sM && aH==sH && S>=0 && S<=2){
    turnItOn = true;
  }
  if(alarm_state==LOW || shakeTimes>=6 || (M==(AM+5))){
    turnItOn = false;
    alarmON=true;
    delay(500);
  } 
  if(analogRead(shakeSensor)>200){
    shakeTimes++;
    Serial.print(shakeTimes);
    delay(50);
  }
  if (turnItOn){
    unsigned long currentMillis = millis();
    if(currentMillis - previousMillis > interval) {
      previousMillis = currentMillis;   
      tone(buzzer,melody[i],100);
      i++; 
      if(i>3){i=0; };
    }
  }
  else{
    noTone(buzzer);
    shakeTimes=0;
  }
}

Download the code from here and open it with Arduino IDE. Inside you will also find the library file.

digitalclockalarm.zip
File Size:	17 kb
File Type:	zip

Download File

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