ESP32 Alarm Clock with DS1302 RTC Module

ESP32 23-02-26

12 0

Tutorial plan

1- Objective of the project

2- Required Components

3- Circuit Connections of system

4- Micropython program of ESP32 Alarm Clock

Objective of the project

The objective of this project is to design and implement a digital alarm clock system using an ESP32 microcontroller, a DS1302 Real-Time Clock (RTC) module, an I2C LCD display, and a buzzer. The system is capable of displaying the current time in real time and activating an audible alarm at a predefined time, such as 07:00:00. This project demonstrates how to integrate timekeeping hardware with a microcontroller to create a practical and interactive embedded system.

Functioning of the System

The system operates by using the DS1302 RTC module to keep track of the current time continuously, even when the ESP32 is powered off, thanks to its backup battery. The ESP32 communicates with the RTC module to read the current hour, minute, and second.

The ESP32 then sends this time information to the LCD I2C display, which shows the current time in a clear format, such as: Hour: 07:00:00

The ESP32 constantly compares the current time from the RTC module with the preset alarm time (07:00:00). When the current time matches the alarm time, the ESP32 activates the buzzer to produce a sound and displays an alarm message on the LCD screen: Alarm 07:00 !!!

The buzzer turns on and off repeatedly to create an audible alert, while the message remains visible on the LCD to inform the user that the alarm has been triggered.

After the alarm duration is completed, the buzzer stops, and the system continues to operate normally, displaying the current time and waiting for the next alarm condition.

Required Components

1. BBC Micro:bit (Microcontroller)

The ESP32 is the main controller of the system. It reads the current time from the DS1302 RTC module, processes the alarm condition, updates the LCD display, and controls the buzzer.

2. DS1302 RTC Module

The DS1302 is a Real-Time Clock (RTC) module used to keep track of the current time and date. It can maintain accurate time even when the ESP32 is powered off because it uses a backup battery. It provides information such as year, month, day, hour, minute, and second. The ESP32 reads this data through digital communication pins.

3. Buzzer

The buzzer is an electronic sound device that produces sound when activated by the ESP32. It is used to alert the user when the alarm time is reached.

4. LCD Display with I2C Module

The LCD display is used to show the current time and alarm messages.

5. Breadboard

Breadboard

A breadboard is used to build the circuit without soldering.

6. Jumper Wires

Jumper wires

Jumper wires are used to connect the ESP32 to the RTC module, the LCD display and the Buzzer. They allow electrical signals and power to flow between the components.

Circuit Connections of system

1- Connection of DS1302 RTC Module to ESP32

DS1302 RTC	ESP32 board
CLK	GPIO 19
DAT	GPIO 18
RST	GPIO 5
VCC	5V
GND	GND

2- Connection of LCD I2C display to ESP32

LCD display	ESP32 board
VCC	5V
GND	GND
SDA	GPIO 21
SCL	GPIO 22

3- Connection of Buzzer to ESP32

Buzzer	ESP32 board
Pin (+)	GPIO 23
Pin (-)	GND

Micropython program of ESP32 Alarm Clock

This MicroPython program implements a digital alarm clock system using an ESP32 microcontroller, a DS1302 Real-Time Clock (RTC) module, an I2C LCD display, and a buzzer.

The purpose of the program is to display the current time continuously and activate an audible alarm when a predefined time is reached.

You need to install this libraries :

i2c_lcd et lcd_api for I2C LCD screen

ds1302 for DS1302 RTC module

# Import the Pin class to control GPIO pins
# and the I2C class for communication with the LCD display
from machine import Pin, I2C

# Import the library to control the I2C LCD display
from i2c_lcd import I2cLcd

# Import the DS1302 RTC (Real Time Clock) module library
import ds1302

# Import the time library for delays
import time


# ================= LCD I2C CONFIGURATION =================

# I2C address of the LCD display (commonly 0x27 or 0x3F)
I2C_ADDR = 0x27

# Initialize the LCD:
# I2C(0) → I2C bus number 0
# scl=Pin(22) → GPIO22 used as I2C clock line
# sda=Pin(21) → GPIO21 used as I2C data line
# 4, 20 → LCD with 4 rows and 20 columns
lcd = I2cLcd(I2C(0, scl=Pin(22), sda=Pin(21)), I2C_ADDR, 4, 20)

# Clear the LCD screen
lcd.clear()


# ================= DS1302 RTC MODULE CONFIGURATION =================

# Define the GPIO pins connected to the RTC module
clk = Pin(19)   # CLK pin (clock signal)
dat = Pin(18)   # DAT pin (data line)
rst = Pin(5)    # RST pin (reset)

# Create the RTC object
rtc = ds1302.DS1302(clk, dat, rst)


# ⚠️ IMPORTANT:
# This line sets the date and time of the RTC module.
# Execute it ONLY ONCE, then comment it to avoid resetting
# the time every time the ESP32 restarts.
rtc.date_time([2026, 2, 6, 5, 6, 59, 55])

# Format:
# [year, month, day, weekday, hour, minute, second]


# ================= BUZZER CONFIGURATION =================

# Set GPIO23 as an output to control the buzzer
buzzer = Pin(23, Pin.OUT)

# buzzer.value(0) → buzzer OFF
# buzzer.value(1) → buzzer ON

# ================= MAIN PROGRAM =================

# Infinite loop
while True:

    # Read the current date and time from the RTC module
    t = rtc.date_time()

    # The list t contains:
    # t[0] = year
    # t[1] = month
    # t[2] = day
    # t[3] = weekday
    # t[4] = hour
    # t[5] = minute
    # t[6] = second


    # Display the title on the first line
    lcd.move_to(0, 0)
    lcd.putstr("ESP32 Clock")


    # Display the time on the second line
    lcd.move_to(0, 1)

    # {:02d} formats numbers with two digits (e.g., 07 instead of 7)
    lcd.putstr("Hour: {:02d}:{:02d}:{:02d}".format(t[4], t[5], t[6]))


    # ================= ALARM CHECK =================

    # If the time is exactly 07:00:00
    if (t[4] == 7) and (t[5] == 0) and (t[6] == 0):

        lcd.move_to(0, 1)

        # Repeat the alarm 10 times
        for i in range(10):

            # Read the current time again
            t = rtc.date_time()

            # Display the updated time
            lcd.move_to(0, 1)
            lcd.putstr("Hour: {:02d}:{:02d}:{:02d}".format(t[4], t[5], t[6]))

            # Display the alarm message
            lcd.move_to(0, 2)
            lcd.putstr('Alarm 07:00 !!!')

            # Turn the buzzer ON
            buzzer.value(1)

            # Wait for 1 second
            time.sleep(1)

            # Read the time again
            t = rtc.date_time()

            # Display the updated time
            lcd.move_to(0, 1)
            lcd.putstr("Hour: {:02d}:{:02d}:{:02d}".format(t[4], t[5], t[6]))

            # Clear the alarm message
            lcd.move_to(0, 2)
            lcd.putstr('               ')

            # Turn the buzzer OFF
            buzzer.value(0)

            # Wait for 1 second
            time.sleep(1)


    # Optional short delay to stabilize display updates
    # time.sleep(0.5)

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# Import the Pin class to control GPIO pins

# and the I2C class for communication with the LCD display

from machine import Pin, I2C

# Import the library to control the I2C LCD display

from i2c_lcd import I2cLcd

# Import the DS1302 RTC (Real Time Clock) module library

import ds1302

# Import the time library for delays

import time

# ================= LCD I2C CONFIGURATION =================

# I2C address of the LCD display (commonly 0x27 or 0x3F)

I2C_ADDR = 0x27

# Initialize the LCD:

# I2C(0) → I2C bus number 0

# scl=Pin(22) → GPIO22 used as I2C clock line

# sda=Pin(21) → GPIO21 used as I2C data line

# 4, 20 → LCD with 4 rows and 20 columns

lcd = I2cLcd(I2C(0, scl=Pin(22), sda=Pin(21)), I2C_ADDR, 4, 20)

# Clear the LCD screen

lcd.clear()

# ================= DS1302 RTC MODULE CONFIGURATION =================

# Define the GPIO pins connected to the RTC module

clk = Pin(19) # CLK pin (clock signal)

dat = Pin(18) # DAT pin (data line)

rst = Pin(5) # RST pin (reset)

# Create the RTC object

rtc = ds1302.DS1302(clk, dat, rst)

# ⚠️ IMPORTANT:

# This line sets the date and time of the RTC module.

# Execute it ONLY ONCE, then comment it to avoid resetting

# the time every time the ESP32 restarts.

rtc.date_time([2026, 2, 6, 5, 6, 59, 55])

# Format:

# [year, month, day, weekday, hour, minute, second]

# ================= BUZZER CONFIGURATION =================

# Set GPIO23 as an output to control the buzzer

buzzer = Pin(23, Pin.OUT)

# buzzer.value(0) → buzzer OFF

# buzzer.value(1) → buzzer ON

# ================= MAIN PROGRAM =================

# Infinite loop

while True:

# Read the current date and time from the RTC module

t = rtc.date_time()

# The list t contains:

# t[0] = year

# t[1] = month

# t[2] = day

# t[3] = weekday

# t[4] = hour

# t[5] = minute

# t[6] = second

# Display the title on the first line

lcd.move_to(0, 0)

lcd.putstr("ESP32 Clock")

# Display the time on the second line

lcd.move_to(0, 1)

# {:02d} formats numbers with two digits (e.g., 07 instead of 7)

lcd.putstr("Hour: {:02d}:{:02d}:{:02d}".format(t[4], t[5], t[6]))

# ================= ALARM CHECK =================

# If the time is exactly 07:00:00

if (t[4] == 7) and (t[5] == 0) and (t[6] == 0):

lcd.move_to(0, 1)

# Repeat the alarm 10 times

for i in range(10):

# Read the current time again

t = rtc.date_time()

# Display the updated time

lcd.move_to(0, 1)

lcd.putstr("Hour: {:02d}:{:02d}:{:02d}".format(t[4], t[5], t[6]))

# Display the alarm message

lcd.move_to(0, 2)

lcd.putstr('Alarm 07:00 !!!')

# Turn the buzzer ON

buzzer.value(1)

# Wait for 1 second

time.sleep(1)

# Read the time again

t = rtc.date_time()

# Display the updated time

lcd.move_to(0, 1)

lcd.putstr("Hour: {:02d}:{:02d}:{:02d}".format(t[4], t[5], t[6]))

# Clear the alarm message

lcd.move_to(0, 2)

lcd.putstr(' ')

# Turn the buzzer OFF

buzzer.value(0)

# Wait for 1 second

time.sleep(1)

# Optional short delay to stabilize display updates

# time.sleep(0.5)

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Tutorial plan

1- Objective of the project

2- Required Components

3- Circuit Connections of system

4- Micropython program of ESP32 Alarm Clock

Objective of the project

Required Components

Circuit Connections of system

Micropython program of ESP32 Alarm Clock

0 comment

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