Arduino-Calculator

arduino based calculator project , which uses arduino nano / uno as mcu ,uses 4x4 matrix keypad for input and 1602 i2c lcd display for calculate doutputs

Arduino Calculator (UNO / Nano)

A simple calculator built using:

• Arduino UNO / Nano
• 16x2 I2C LCD Display
• 4x4 Matrix Keypad

It performs basic operations: + − × ÷

If you prefer video guidance, watch the full tutorial here:
📺 https://youtu.be/s7fe-LROB0o?si=2Rme3poVYnrOcxCS

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📦 How to Use

1️⃣ Download the Project

• Click Code → Download ZIP
• Extract the folder

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2️⃣ Install the LCD Library

Inside this repo there is a folder named library

👉 Copy the entire LiquidCrystal_I2C folder
👉 Paste it into your Arduino libraries folder:

Windows: Documents → Arduino → libraries

If the libraries folder does not exist, create it.

After copying, restart Arduino IDE.

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3️⃣ Open the Main File

Open: calculator_main.ino

Select your board:

• Tools → Board → Arduino UNO (or Nano)
• Select correct COM port
• Click Upload

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🔌 Pin Connections

📟 I2C LCD (16x2)

LCD Pin	Arduino
VCC	5V
GND	GND
SDA	A4 (UNO/Nano)
SCL	A5 (UNO/Nano)

Default I2C Address: 0x27

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🔢 4x4 Keypad

Keypad Row Pins	Arduino
R1	9
R2	8
R3	7
R4	6

Keypad Column Pins	Arduino
C1	5
C2	4
C3	3
C4	2

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➕ Extra Buttons

Button	Arduino Pin
= (Equals)	11
Backspace	12

Both buttons should connect to GND when pressed
(Pins are configured as INPUT_PULLUP internally)

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🧠 How It Works

• Keypad collects input
• Expression is displayed on LCD
• Press = to calculate
• Result appears on second row
• Press C to clear

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📁 Project Structure

calculator_main.ino basic/ library/ calc_circuit_diagram.png

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If something is unclear, please watch the full YouTube tutorial linked above.

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Made for learning.
Simple. Clean. Functional.