Arduino Calculator - 4x4 Keypad & I2C LCD

A simple calculator built using an Arduino Uno, a 4x4 keypad, and an I2C LCD screen. This project allows users to input two numbers, choose a basic operation (+, -, *, /), and view the result on the LCD. It was created as part of a university project, where I contributed to the code development and logic design.

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🛠Features

• Input two numbers using a 4x4 keypad.
• Choose operation: +, -, *, /.
• Display result when = is pressed.
• Clear screen with C button.
• Scrolling welcome message on startup.

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📷 Hardware Used

Component	Description
Arduino Uno	Microcontroller board
4x4 Keypad	For inputting numbers and operations
I2C LCD (16x2)	To display input and results
Jumper Wires & Breadboard	For connections

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📌 Circuit Overview

• Keypad Rows (R1–R4) connected to Arduino pins 9, 8, 7, 6
• Keypad Columns (C1–C4) connected to Arduino pins 5, 4, 3, 2
• I2C LCD ​​connected via A4 (SDA) and A5 (SCL)

Note: The I2C address used in the code is 0x27. If your LCD uses a different address, modify it accordingly.

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🚀How It Works

1. Power the Arduino.
2. A welcome message scrolls on the LCD.
3. Enter the first number via keypad.
4. Press the operation key (+, -, *, or /).
5. Enter the second number.
6. Press = to calculate and display the result.
7. Press C to clear the screen and reset.

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📂 Project Files

• Arduino_Calculator.ino: Main code
• README.md: Project documentation

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🙋‍♂️ Contributions

This project was implemented in collaboration with a university colleague. I contributed to:

• Writing and structuring the Arduino code -Designing the interaction logic
• Testing and debugging the calculator functionality

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📸 Demo (Optional)

If you have a picture or video of the setup, you can embed it here:

![Project Demo](/main/images/Arduino_Calculator-3.jpg)

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🌐 Let's Connect