This clock is the basis of many of my projects.

I was inspired by a friend who has published a tutorial in 2012 (link)

It is a simple clock with LCD display, an RTC (real time clock) and 3 buttons.

For convenience and to save pin dell'Arduino, I used a display with I2C module.

The RTC also uses the I2c protocol.

The 3 buttons, connected to a "pull down" circuit, are used to adjust or change the time and date of the watch, without having to reload the Arduino code.

Step 1: Material

Arduino or Arduino standalone
RTC DS1307
LCD 20x4 I2c
3 buttons
3 Resistor 10k ohm
Wires

Step 2: Schematics

The scheme is very simple:

The LCD and RTC communicate with Arduino through the I2C protocol and the library "Wire" and are connected to ARDUINO to Pin A4 and A5.

LCD & RTC---------------------- ARDUINO PIN

SDA ---------------------------------------A4

SLC----------------------------------------A5

simple clock.fzz
Download

Step 3: Arduino Code

Link libraries:

Wire.h :by Arduino IDE

RTClib.h

LiquidCrystal_I2C.h

Code:https://create.arduino.cc/editor/Tittiamo/01f86512-a8a9-4a92-830a-5ab2067c5583/preview

The code is very simple:
In the loop, check if the "menu" button is pressed, if it is not pressed displays the date and time, otherwise it counts how many times you pressed the button and, through the various sets, adjusts the time. In the end, updates the RTC with the new data entered and displays the Date and Time