Simple Arduino based Alarm Clock with DS1302 RTC
Hello everyone, in this project we’ll try to make an easy alarm clock with Arduino UNO board, this project is a mix of different modules that I used before, if you’re stuck on something you can check in the website for the module tutorial, because that’s how I usually work: Do things separately and then start mixing :D.
You’ll need to check:
- How to simply use DS1302 RTC module with Arduino board and LCD screen
- Arduino LCD I2C simple use and direct write from serial monitor
- Arduino uno + 4×4 Keypad Matrix + LCD i2c screen
- How to use a buzzer/piezo speaker with Arduino
- How to setup DS1302 RTC module with Keypad + Arduino + LCD
For this project we will need:
Arduino UNO Board, or you can use what suits you:

DS1302 RTC module:

4*4 Matrix Keypad module:

LCD i2c screen:

Buzzer module, or the 2 pins buzzer:

Wiring:
Libraries:
- LCD i2c library You can chose this or download your own
- Keypad library Or you can download it from Arduino IDE
- RTC DS1302 virtuabotix library
Code:
(Major changes were made 12/04/18)
Code functioning is pretty simple, after wiring the module you can press “*” to set the time and date on the DS1302 RTC, the display will show then the current day and time if you want to set the alarm you press “A” and you can set which hour and minute, and you can deactivate it by pressing “B” before time or pressing any button while ringing.
The code was made in an easy to understand and beginners’s way, it wasn’t meant to handle multiple alarms,a lot of people ask about this, but you can do it in case you don’t care about clumsy code.
Download here: RTC_alarm_clock.ino or check below:
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//This code is to use with DS1302 RTC module + 4*4 Keypad + LCD i2c + Arduino + Buzzer //After wiring the modules, the LCD will show the default date and time or the one set before //The objective of this project is that you can set the RTC module from the keypad, and sure it will stay stored //Then show it on the screen and after you can set your alarm. //Refer to https://www.surtrtech.com or SurtrTech youtube channel for more information #include <Keypad.h> //Libraries needed #include <virtuabotixRTC.h> #include <LiquidCrystal_I2C.h> #define I2C_ADDR 0x27 //LCD i2c stuff #define BACKLIGHT_PIN 3 #define En_pin 2 #define Rw_pin 1 #define Rs_pin 0 #define D4_pin 4 #define D5_pin 5 #define D6_pin 6 #define D7_pin 7 LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin); virtuabotixRTC myRTC(2, 3, 4); //Wiring of the RTC (CLK,DAT,RST) //If you change the wiring change the pins here also const byte numRows= 4; //number of rows on the keypad const byte numCols= 4; //number of columns on the keypad //keymap defines the key pressed according to the row and columns just as appears on the keypad char keymap[numRows][numCols]= { {'1', '2', '3', 'A'}, {'4', '5', '6', 'B'}, {'7', '8', '9', 'C'}, {'*', '0', '#', 'D'} }; byte rowPins[numRows] = {12,11,10,9}; //Rows 0 to 3 //if you modify your pins you should modify this too byte colPins[numCols]= {8,7,6,5}; //Columns 0 to 3 int i1,i2,i3,i4; char c1,c2,c3,c4; char keypressed,keypressedx; int A_hour=NULL; int A_minute=NULL; int AlarmIsActive=NULL; int buzzer = 13; Keypad myKeypad= Keypad(makeKeymap(keymap), rowPins, colPins, numRows, numCols); void setup() { Serial.begin(9600); lcd.begin (16,2); //Initialize the LCD lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE); lcd.setBacklight(HIGH); lcd.home (); } void loop() { while(keypressed == NO_KEY){ //As long as no key is pressed we keep showing the date and time, I'm obliged to clear the screen everytime so the numbers don't get confused //And I should add that little delay so the screen shows correctly otherwise it didn't work for me keypressed = myKeypad.getKey(); lcd.clear(); //Here after clearing the LCD we take the time from the module and print it on the screen with usual LCD functions myRTC.updateTime(); if(myRTC.hours==A_hour && myRTC.minutes==A_minute && AlarmIsActive==1 && myRTC.seconds >= 0 && myRTC.seconds <= 2){ while(keypressedx == NO_KEY){ tone(buzzer, 1000); //You can modify the tone or make your own sound delay(100); tone(buzzer, 2000); delay(100); lcd.clear(); lcd.print("Get up !!!"); //Message to show when the alarm is ringing keypressedx = myKeypad.getKey(); } } keypressedx = NO_KEY; noTone(buzzer); lcd.setCursor(0,0); lcd.print(myRTC.dayofmonth); lcd.print("/"); lcd.print(myRTC.month); lcd.print("/"); lcd.print(myRTC.year); lcd.setCursor(0,1); lcd.print(myRTC.hours); lcd.print(":"); lcd.print(myRTC.minutes); lcd.print(":"); lcd.print(myRTC.seconds); delay(100); } if (keypressed == '*') //As we everytime check the key pressed we only proceed to setup if we press "*" { lcd.clear(); lcd.print(" Setup"); delay(1000); lcd.clear(); lcd.print("Setup year"); //So you can understand how this works, first it shows us "setup" then it prints "setup year" and now you can write your year normally (2-0-1-8) //It automatically passes to setting up the month...until it's finished //The keys from keypad are all considered chars (c) so we should convert them to int that's what I did then we store them (i) //We do some math and we get the year, month... as int so we can inject them to the RTC otherwise it will not be compiled //Months like April you should write 04, 03 for March... otherwise it will not pass to the next parameter //The RTC virtuabotix library is already set to not accept strange time and dates (45/17/1990) (58:90:70), and yes old dates are considered as errors char keypressed2 = myKeypad.waitForKey(); if (keypressed2 != NO_KEY && keypressed2 !='*' && keypressed2 !='#' && keypressed2 !='A' && keypressed2 !='B' && keypressed2 !='C' && keypressed2 !='D' ) { c1 = keypressed2; lcd.setCursor(0, 1); lcd.print(c1); } char keypressed3 = myKeypad.waitForKey(); if (keypressed3 != NO_KEY && keypressed3 !='*' && keypressed3 !='#' && keypressed3 !='A' && keypressed3 !='B' && keypressed3 !='C' && keypressed3 !='D' ) { c2 = keypressed3; lcd.setCursor(1, 1); lcd.print(c2); } char keypressed4 = myKeypad.waitForKey(); if (keypressed4 != NO_KEY && keypressed4 !='*' && keypressed4 !='#' && keypressed4 !='A' && keypressed4 !='B' && keypressed4 !='C' && keypressed4 !='D' ) { c3 = keypressed4; lcd.setCursor(2, 1); lcd.print(c3); } char keypressed5 = myKeypad.waitForKey(); if (keypressed5 != NO_KEY && keypressed5 !='*' && keypressed5 !='#' && keypressed5 !='A' && keypressed5 !='B' && keypressed5 !='C' && keypressed5 !='D' ) { c4 = keypressed5; lcd.setCursor(3, 1); lcd.print(c4); } i1=(c1-48)*1000; //the keys pressed are stored into chars I convert them to int then i did some multiplication to get the code as an int of xxxx i2=(c2-48)*100; i3=(c3-48)*10; i4=c4-48; int N_year=i1+i2+i3+i4; delay(500); lcd.clear(); lcd.print("Setup month"); //////////////////////////////////////////////////////////////// char keypressed6 = myKeypad.waitForKey(); // here all programs are stopped until you enter the four digits then it gets compared to the code above if (keypressed6 != NO_KEY && keypressed6 !='*' && keypressed6 !='#' && keypressed6 !='A' && keypressed6 !='B' && keypressed6 !='C' && keypressed6 !='D' ) { c1 = keypressed6; lcd.setCursor(0, 1); lcd.print(c1); } char keypressed7 = myKeypad.waitForKey(); if (keypressed7 != NO_KEY && keypressed7 !='*' && keypressed7 !='#' && keypressed7 !='A' && keypressed7 !='B' && keypressed7 !='C' && keypressed7 !='D' ) { c2 = keypressed7; lcd.setCursor(1, 1); lcd.print(c2); } i1=(c1-48)*10; i2=c2-48; int N_month=i1+i2; delay(500); lcd.clear(); lcd.print("Setup Day"); //////////////////////////////////////////////////////////////// char keypressed8 = myKeypad.waitForKey(); // here all programs are stopped until you enter the four digits then it gets compared to the code above if (keypressed8 != NO_KEY && keypressed8 !='*' && keypressed8 !='#' && keypressed8 !='A' && keypressed8 !='B' && keypressed8 !='C' && keypressed8 !='D' ) { c1 = keypressed8; lcd.setCursor(0, 1); lcd.print(c1); } char keypressed9 = myKeypad.waitForKey(); if (keypressed9 != NO_KEY && keypressed9 !='*' && keypressed9 !='#' && keypressed9 !='A' && keypressed9 !='B' && keypressed9 !='C' && keypressed9 !='D' ) { c2 = keypressed9; lcd.setCursor(1, 1); lcd.print(c2); } i1=(c1-48)*10; i2=c2-48; int N_day=i1+i2; delay(500); lcd.clear(); lcd.print("Setup hour"); ////////////////////////////////////////////////////////////////////////////////////: char keypressed10 = myKeypad.waitForKey(); // here all programs are stopped until you enter the four digits then it gets compared to the code above if (keypressed10 != NO_KEY && keypressed10 !='*' && keypressed10 !='#' && keypressed10 !='A' && keypressed10 !='B' && keypressed10 !='C' && keypressed10 !='D' ) { c1 = keypressed10; lcd.setCursor(0, 1); lcd.print(c1); } char keypressed11 = myKeypad.waitForKey(); if (keypressed11 != NO_KEY && keypressed11 !='*' && keypressed11 !='#' && keypressed11 !='A' && keypressed11 !='B' && keypressed11 !='C' && keypressed11 !='D' ) { c2 = keypressed11; lcd.setCursor(1, 1); lcd.print(c2); } i1=(c1-48)*10; i2=c2-48; int N_hour=i1+i2; delay(500); lcd.clear(); lcd.print("Setup minutes"); ////////////////////////////////////////////////////////////////////////////////////: char keypressed12 = myKeypad.waitForKey(); // here all programs are stopped until you enter the four digits then it gets compared to the code above if (keypressed12 != NO_KEY && keypressed12 !='*' && keypressed12 !='#' && keypressed12 !='A' && keypressed12 !='B' && keypressed12 !='C' && keypressed12 !='D' ) { c1 = keypressed12; lcd.setCursor(0, 1); lcd.print(c1); } char keypressed13 = myKeypad.waitForKey(); if (keypressed13 != NO_KEY && keypressed13 !='*' && keypressed13 !='#' && keypressed13 !='A' && keypressed13 !='B' && keypressed13 !='C' && keypressed13 !='D' ) { c2 = keypressed13; lcd.setCursor(1, 1); lcd.print(c2); } i1=(c1-48)*10; i2=c2-48; int N_minutes=i1+i2; delay(500); lcd.clear(); myRTC.setDS1302Time(22, N_minutes, N_hour, 1, N_day, N_month, N_year); //once we're done setting the date and time we transfer to values to the RTC module //the 22 stands for seconds you can add a setup for it too if you want //the 1 stands for day of the week, as long I don't show it on the screen I don't change it keypressed=NO_KEY; //the "*" key is stored in "keypressed" so I remove that value from it otherwise it will get me in the setup again } /////////////////////////////////////////Alarme setup///////////////////////////////// if (keypressed == 'A'){ lcd.clear(); lcd.print(" Alarm setup "); delay(1000); lcd.clear(); lcd.print("Set alarm hour"); char keypressed14 = myKeypad.waitForKey(); // here all programs are stopped until you enter the four digits then it gets compared to the code above if (keypressed14 != NO_KEY && keypressed14 !='*' && keypressed14 !='#' && keypressed14 !='A' && keypressed14 !='B' && keypressed14 !='C' && keypressed14 !='D' ) { c1 = keypressed14; lcd.setCursor(0, 1); lcd.print(c1); } char keypressed15 = myKeypad.waitForKey(); if (keypressed15 != NO_KEY && keypressed15 !='*' && keypressed15 !='#' && keypressed15 !='A' && keypressed15 !='B' && keypressed15 !='C' && keypressed15 !='D' ) { c2 = keypressed15; lcd.setCursor(1, 1); lcd.print(c2); } i1=(c1-48)*10; i2=c2-48; A_hour=i1+i2; delay(500); lcd.clear(); lcd.print("Set alarm minutes"); char keypressed16 = myKeypad.waitForKey(); // here all programs are stopped until you enter the four digits then it gets compared to the code above if (keypressed16 != NO_KEY && keypressed16 !='*' && keypressed16 !='#' && keypressed16 !='A' && keypressed16 !='B' && keypressed16 !='C' && keypressed16 !='D' ) { c1 = keypressed16; lcd.setCursor(0, 1); lcd.print(c1); } char keypressed17 = myKeypad.waitForKey(); if (keypressed17 != NO_KEY && keypressed17 !='*' && keypressed17 !='#' && keypressed17 !='A' && keypressed17 !='B' && keypressed17 !='C' && keypressed17 !='D' ) { c2 = keypressed17; lcd.setCursor(1, 1); lcd.print(c2); } i1=(c1-48)*10; i2=c2-48; A_minute=i1+i2; delay(500); lcd.clear(); AlarmIsActive=1; keypressed=NO_KEY; } if (keypressed == 'B') { lcd.clear(); lcd.print("Alarm deactivated"); AlarmIsActive=0; keypressed=NO_KEY; delay(500); } else { myRTC.updateTime(); keypressed=NO_KEY; } } |
I hope you like it, any problem you can contact me.
Categories
Yassine View All
Automation and Electrical Engineer, Electronics amateur trying to share my little projects.
Hi, very interesting project, I’m beginner in this field. Could you tell me please, is it a lot to change the RTC module for another one (1307 or 3231)?
Hi, you should modify the wiring, library and all the functions related to the RTC.
I have a list off 1825 alarmmoments that I want to set with arduino. You help me to figure out how can I build this?
Thanks
Could I use a simple Active buzzer instead of a buzzer module?
Hi nice rreading your blog
THE CODE IS SHOWING LOT OF ERRORS PLEASE HELP