🔐 Digital Door Lock using Arduino

This project demonstrates a secure and smart digital door lock system built using Arduino Nano. It utilizes a 4x4 keypad for user input, an LCD display for real-time feedback, and a servo motor to physically lock or unlock the door. This system is ideal for basic home or office security projects.

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📌 Features

• Password-protected door locking system
• Real-time LCD feedback
• Servo motor-based locking mechanism
• Easy hardware integration with Arduino Nano
• Prototype made using Styrofoam for demonstration

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🧰 Components Used

Component	Description
Arduino Nano	Main controller for processing input and controlling output
4x4 Keypad Module	Used to enter the password
SG90 Servo Motor	Acts as the door lock actuator
I2C 16x2 LCD	Displays status messages to the user
Breadboard	For assembling the circuit without soldering
Jumper Wires	For electrical connections
Door Lock & Styrofoam	For creating a model prototype of the locking system
5V DC Adapter	Powers Arduino Uno and components externally

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⚙️ Working Principle

1. Initialization:

   • LCD displays: WELCOME TO DOOR LOCK SYSTEM
   • System is ready to receive input.

2. Password Entry:

   • User enters password via keypad.
   • LCD displays: Enter Password and shows the digits.

3. Validation:

   • If password is correct, servo motor rotates to unlock the door.
   • If incorrect, the lock remains engaged.

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🔄 Workflow Summary

1. Arduino Setup:
   • Arduino Nano acts as the main controller.
2. Hardware Connections:
   • Keypad connected to D2-D9
   • Servo connected to D11
   • I2C LCD connected to A4 (SDA) and A5 (SCL)
3. Code Upload:
   • Use Arduino IDE to upload the code to the Nano.
4. Enclosure Build:
   • Components installed in a Styrofoam model for demonstration.

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📷 Connection

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🛠️ How to Build

• Connect all components as described in the schematic.
• Power up the Arduino Nano.
• Upload the code.
• Input the password using the keypad.
• Watch the servo motor engage or remain static depending on correctness.

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📄 Project Report

A detailed project report is available in the attached PDF file, which includes:

• Component descriptions
• Circuit explanation
• Flowchart
• Working logic
• Conclusion

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📬 Authors

• Project developed by a student team as part of a learning activity in Arduino-based security systems.

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Developed as a part of the Digital Electronics Lab Project at Daffodil International University.