ESP8266 Digital Alarm Clock with DS1302 RTC and LCD I2C

ESP8266 26-02-26

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Tutorial plan

1- Objective of the project

2- Required Components

3- Circuit Connections of system

4- Micropython program of ESP8266 Alarm Clock

Objective of the project

This project aims to build a digital alarm clock using the ESP8266, DS1302 RTC module, LCD I2C display, and a buzzer.
The system displays the current time in real-time and activates an alarm sound when the preset alarm time is reached. It is a practical embedded systems project that demonstrates how to interface a microcontroller with a real-time clock and output devices.

Working Principle

The DS1302 RTC module keeps track of the current time (hours, minutes, and seconds), even when power is disconnected thanks to its backup battery.

The ESP8266 reads the time from the RTC and displays it on the LCD I2C screen in digital format. At the same time, it continuously compares the current time with the preset alarm time.

When both times match, the buzzer is activated and an alarm message is displayed on the LCD. The system then continues running and updating the time automatically.

This project shows how to create a simple and reliable standalone alarm clock using ESP8266.

Required Components

1. ESP8266 NodeMCU

The ESP8266 NodeMCU, developed by Espressif Systems, is the main microcontroller of the system. It reads the current time from the RTC module, displays it on the LCD, and controls the buzzer when the alarm time is reached.

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 ESP82866 is powered off because it uses a backup battery. It provides information such as year, month, day, hour, minute, and second. The ESP8266 reads this data through digital communication pins.

4. Buzzer

The buzzer is an output device that produces sound when the alarm time is reached. It alerts the user that the preset alarm time has occurred. The ESP8266 activates the buzzer by sending a digital signal.

4. LCD Display with I2C Module

he LCD I2C display is used to show the current time and alarm messages.

5. Breadboard

Breadboard

The breadboard is used to assemble the circuit without soldering. It makes it easy to connect and modify components during testing and development.

6. Jumper Wires

Jumper wires

The jumper wires are used to connect the ESP8266 with the RTC module, LCD display, and buzzer. They ensure proper electrical connections between all components.

Circuit Connections of system

1- Connection of DS1302 RTC Module to ESP8266

DS1302 RTC	ESP8266 NodeMCU
CLK	D5 (GPIO 14)
DAT	D6 (GPIO 12)
RST	D7 (GPIO 14)
VCC	3V
GND	GND

2- Connection of LCD I2C display to ESP8266

LCD display	ESP8266 NodeMCU
VCC	VIN
GND	GND
SDA	D2 (GPIO4)
SCL	D1 (GPIO5)

3- Connection of Buzzer to ESP8266 NodeMCU

Buzzer	ESP8266 NodeMCU
Pin (+)	D0 (GPIO 0)
Pin (-)	GND

Micropython program of ESP8266 Alarm Clock

This program implements a digital alarm clock system using an ESP8266 NodeMCU, a DS1302 RTC module, an I2C LCD display, and a buzzer.

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 used 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 to create delays
import time


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

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

# Initialize the LCD display:
# 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 signal)

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


# ⚠️ IMPORTANT:
# This line sets the date and time of the RTC module.
# Run this line ONLY ONCE, then comment it,
# otherwise the time will reset 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 =================

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

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


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

# Infinite loop to keep the clock running continuously
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 of the LCD
    lcd.move_to(0, 0)
    lcd.putstr("ESP32 Clock")


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

    # {:02d} ensures numbers are always displayed with two digits
    # Example: 07 instead of 7
    lcd.putstr("Hour: {:02d}:{:02d}:{:02d}".format(t[4], t[5], t[6]))


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

    # Check if the current 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 on the third line
            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)

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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 used 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 to create delays

import time

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

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

I2C_ADDR = 0x27

# Initialize the LCD display:

# 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 signal)

# Create the RTC object to communicate with the DS1302 module

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

# ⚠️ IMPORTANT:

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

# Run this line ONLY ONCE, then comment it,

# otherwise the time will reset 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 =================

# Configure GPIO23 as an output pin to control the buzzer

buzzer = Pin(23, Pin.OUT)

# buzzer.value(0) → turn buzzer OFF

# buzzer.value(1) → turn buzzer ON

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

# Infinite loop to keep the clock running continuously

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 of the LCD

lcd.move_to(0, 0)

lcd.putstr("ESP32 Clock")

# Display the current time on the second line

lcd.move_to(0, 1)

# {:02d} ensures numbers are always displayed with two digits

# Example: 07 instead of 7

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

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

# Check if the current 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 on the third line

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)

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ESP8266 Digital Alarm Clock with DS1302 RTC and LCD I2C

Tutorial plan

1- Objective of the project

2- Required Components

3- Circuit Connections of system

4- Micropython program of ESP8266 Alarm Clock

Objective of the project

Required Components

Circuit Connections of system

Micropython program of ESP8266 Alarm Clock

0 comment

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