Arduino based Real-Time Digital Clock

The Arduino-based Real-Time Digital Clock system operates by combining a microcontroller, a real-time clock module, and an alphanumeric display. At the heart of the system is the Arduino Uno, which executes code written via the Arduino IDE to fetch, process, and display time data. The primary timekeeping source is the RTC DS3231 module (MOD1), which communicates with the Arduino and maintains accurate timekeeping via an internal crystal oscillator. A CR2032 coin cell battery is housed within the RTC module to provide uninterrupted backup power, ensuring the time is preserved even when the primary external power source is disconnected. Power for the entire circuit is delivered via a 12V, 2A power adaptor plugged into the Arduino. Visual output is handled by the LCD (JHD 204A / 1602 I2C / SPI, MOD2), which receives formatted time strings from the Arduino and renders them on screen. A 10k potentiometer (P1) is integrated into the circuit to manually adjust the contrast of the LCD screen for optimal visibility. Additionally, a 220 ohm resistor (R1) is utilized for current-limiting purposes, protecting components such as the LCD backlight from excessive current. Male-female jumper wires (20 units) establish secure electrical connections between the Arduino Uno pins, the RTC module, the LCD, and the passive components on the breadboard or terminal points. Together, this configuration continuously queries the RTC for hours, minutes, and seconds, updating the display in real time.