# RTC Clock

Day 9 of the 100 Days 100 IoT Projects collection. Board: ESP8266.

A DS3231 real-time clock keeps time for the ESP8266, printed to the serial monitor. Learn I2C communication and battery-backed timekeeping.

## How it works

The DS3231 keeps time independently on its own coin cell, even when the ESP8266 loses power. The board queries the chip over I2C, reads the time registers, and prints a formatted clock to the serial monitor. It is the simplest honest clock you can build.

## What you'll learn

- I2C register reads
- Battery-backed timekeeping
- RTC vs NTP tradeoffs
- Serial monitor debugging

Full project (code, wiring diagram, Wokwi simulation): https://github.com/kritishmohapatra/100_Days_100_IoT_Projects/tree/main/Basic_RTC_Clock_(_Serial_Monitor_Display_)

Summary by SkillShop. Code and diagrams belong to the original repo.