Overview
Things
Story

So, it's a clock
How to build
How to use
And that's the project
Happy building

Published February 28, 2024 © GPL3+

EASY Arduino Alarm Clock (w/ Matrix Display)

A functioning alarm clock with an easily adjustable alarm time, a matrix display, and a nice case to go with it!

BeginnerFull instructions provided556

EASY Arduino Alarm Clock (w/ Matrix Display)

Things used in this project

Hardware components

Arduino UNO

Breadboard (generic)

Buzzer

DFRobot DS3231M MEMS Precise RTC

LED Dot Matrix Display, Red

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Hot glue gun (generic)

Optional

Story

So, it's a clock.

oh my god whaaaat

Yeah, there's not much to say about the finished product.

Let's just move on to the building part.

How to build?

First, grab an RTC Module and a Piezo Buzzer.

Connect:

RTC GND to GND
RTC VCC to VCC
RTC SDA to SDA
RTC SCL to SCL
Buzzer GND to GND
Buzzer signal to pin 3
Buzzer VCC to VCC (i think some require this but mine doesn't)

I chose to use this tiny breadboard to fit all the internals.

Internals

Next, grab 4 LED Matrixes.

Mine came connected together.

Next, connect:

VCC to VCC
GND to GND
DIN to Pin 6
CS to Pin 5
CLK to Pin 4

Now, this is the part where you can stray away from the guide.

You need to make a case to hold all the circuitry, and an area to hold the screen.

I opted for some cardboard, hot glue, and a random hinge to make mine.

My case. It's got a hinge to open the top, a port on the side for the board, and a section for the screen.

You can do whatever you want though.

And that's the build!

Now, on to using it!

How to use?

To get the time working, just plug it in and upload the code.

 rtc.adjust(DateTime(F(__DATE__),F(__TIME__)));

This line will take care of that for you.

To adjust the alarm time, edit this line:

int ALARMHOUR = 16;
int ALARMMINUTE = 07;

ALARMHOUR is the hour the alarm will go off (NOTE: THIS IS IN 24 HR TIME)

ALARMMINUTE is the minute time.

Ex: HOUR = 13, MINUTE = 23, Alarm will go off at 1:23 PM

I also added an additional debug feature for the alarm.

Typing "a" into the serial monitor will trigger the alarm to go off.

There's also a debugTime() function you can uncomment if you're having issues with the RTC.

And that's the project!

Happy building!

matrix_alarm_clock.ino

#include <RTClib.h>
#include <Wire.h>
RTC_DS3231 rtc;
char t[32];

#include "MD_Parola.h"
#include "MD_MAX72xx.h"
#include "SPI.h"

#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
#define MAX_DEVICES 4
#define CS_PIN 5
#define DATA_PIN 6
#define CLK_PIN 4
MD_Parola myDisplay = MD_Parola(HARDWARE_TYPE, DATA_PIN, CLK_PIN, CS_PIN, MAX_DEVICES);

byte BUZZER = 3;

int ALARMHOUR = 16;
int ALARMMINUTE = 07;

void checkAlarm() {
  DateTime now = rtc.now();
  if (now.hour() == ALARMHOUR && now.minute() == ALARMMINUTE || Serial.read() == 'a') {
    tone(BUZZER, 250, 400);
    delay(1000);
    tone(BUZZER, 250, 400);
    delay(1000);
    tone(BUZZER, 250, 400);
    delay(1000);
    tone(BUZZER, 250, 400);
    delay(1000);
  }
}

void debugTime() {
  DateTime now = rtc.now();
  Serial.print(now.hour());
  Serial.print(" ");
  Serial.print(now.twelveHour());
  Serial.print(" ");
  Serial.print(now.minute());
  Serial.print(" ");
  Serial.print(now.second());
  Serial.print(" ");
  Serial.print(now.isPM());
  Serial.println(" ");
}

void setup()
{
  myDisplay.begin();
  myDisplay.setIntensity(0);
  myDisplay.setTextAlignment(PA_CENTER);
  myDisplay.setCharSpacing(1);
  myDisplay.displayClear();

  Serial.begin(9600);

  Wire.begin();
  rtc.begin();
  rtc.adjust(DateTime(F(__DATE__),F(__TIME__)));

  if (rtc.lostPower()) {
    Serial.println("rtc.lostpower");
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }
}
void loop()
{
  DateTime now = rtc.now();
  sprintf(t, "%02d:%02d", now.twelveHour(), now.minute());  
  myDisplay.print(t);
  Serial.println(t);
  Serial.println(now.timestamp(DateTime::TIMESTAMP_FULL));
  checkAlarm();
  //debugTime();
  delay(1000);
}

Credits

BlueJay

4 projects • 2 followers

a guy who makes stuff :D been tinkering with arduino for some time, and am starting to get more advanced ^_^

EASY Arduino Alarm Clock (w/ Matrix Display)

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

So, it's a clock.

How to build?

How to use?

And that's the project!

Happy building!

Code

matrix_alarm_clock.ino

GitHub

Credits

BlueJay

Comments

Embed the widget on your own site

EASY Arduino Alarm Clock (w/ Matrix Display)

EASY Arduino Alarm Clock (w/ Matrix Display)

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

So, it's a clock.

How to build?

How to use?

And that's the project!

Happy building!

Code

matrix_alarm_clock.ino

GitHub

Credits

BlueJay

Comments

Related channels and tags