🔐 Digital Safe Lock System

A password based digital security lock system developed using Arduino UNO and Embedded C.The system uses a 4×4 matrix keypad for password entry, EEPROM for permanent password storage, a 16×2 LCD for user interaction, a servo motor for lock/unlock operation, and a buzzer for security alerts.

📌 Project Overview

Developed a password-based digital security system using Arduino Uno for controlled access and electronic locking.

The system integrates a 4×4 matrix keypad, EEPROM, 16×2 LCD, servo motor, and buzzer to implement password authentication, non-volatile password storage, and physical lock control.

🎯 Objective

To design and implement an embedded access-control system that provides:

• Password-based authentication
• Non-volatile password storage
• Electronic locking and unlocking
• User feedback through an LCD
• Security alerts for incorrect passwords

⚙️ System Working

1. The user enters a 4-digit password through the 4×4 matrix keypad.
2. Arduino performs row-column matrix scanning to identify the pressed key.
3. The entered password is compared with the password stored in EEPROM.
4. If the password is correct, the servo motor unlocks the system.
5. If the password is incorrect, the system remains locked and the buzzer generates an alert.
6. The 16×2 LCD displays the current system status.
7. A password-reset mechanism allows the stored password to be updated.

🔧 Hardware Components

💻 Technical Implementation

• Embedded C / Arduino C for application logic and system control
• GPIO-based matrix scanning for keypad interfacing
• EEPROM read/write operations for persistent password storage
• Servo control for electronic lock actuation
• LCD interfacing for real-time user feedback
• Modular programming using user-defined functions
• Hardware-software integration and debugging

🔑 Key Features

• 🔐 4-digit password authentication
• 💾 Non-volatile password storage using EEPROM
• ⌨️ 4×4 matrix keypad interfacing
• 🔒 Servo-based electronic locking
• 🖥️ LCD-based system status display
• 🔊 Incorrect-password alert
• 🔄 Password reset functionality
• 🚫 Keypad scanning implemented without the Keypad library

📸 Project Demonstration

Wokwi Circuit

📊 Project Workflow

                 ┌──────────────────┐
                 │   4×4 Keypad     │
                 │  Password Input  │
                 └────────┬─────────┘
                          │
                          ▼
                 ┌──────────────────┐
                 │    Arduino Uno   │
                 │                  │
                 │  Keypad Scanning │
                 │  Authentication  │
                 │  EEPROM Handling │
                 └───────┬──────────┘
                         │
              ┌──────────┼──────────┐
              │          │          │
              ▼          ▼          ▼
        ┌──────────┐ ┌────────┐ ┌─────────┐
        │   LCD    │ │ Servo  │ │ Buzzer  │
        │ Display  │ │  Lock  │ │  Alert  │
        └──────────┘ └────────┘ └─────────┘

Built With

• 4*4keypad
• arduinouno
• c++
• eeprom
• embeddedc
• lcd
• servomotor