🔐 Smart Blockchain-Based Door Lock System A Secure, Decentralized, and Biometric-Based Access Control System
This project integrates biometric authentication (fingerprint recognition) with blockchain technology to create a tamper-proof, secure, and decentralized door lock system. Utilising Ethereum smart contracts, all access attempts are recorded transparently, eliminating security risks associated with traditional centralized databases.
Video demo link: https://drive.google.com/file/d/147HnpRNge7AVKz-W2D68FLpSRysKWj2X/view?usp=drive_link
Features
- Fingerprint Authentication – Ensures only authorized users can unlock the door.
- Blockchain Security – Stores access logs on Ethereum for transparency and immutability.
- Admin Approval via MetaMask – Unauthorized access attempts trigger an admin request.
- Web Dashboard (React.js) – Real-time monitoring and management of access logs.
- IoT Integration (Arduino Uno + Servo Motor) – Physically unlocks/locks the door upon successful authentication.
4-Layer Architecture of the system
🛠️ Tech Stack
Hardware:
Arduino Uno – Controls fingerprint sensor and lock mechanism.
Fingerprint Sensor – Captures user authentication data.
Servo Motor – Acts as the physical lock/unlock mechanism.
12V Relay – Controls door locking via Arduino.
Software:
Frontend: React.js (User Interface & Access Logs Monitoring)
Backend: Node.js + Express.js (Handles authentication & blockchain interaction)
Blockchain: Ethereum (Solidity Smart Contracts, Hardhat for testing)
Web3.js: Facilitates Ethereum interactions with MetaMask
🔄 Working Mechanism
- User places their finger on the fingerprint sensor → Data is sent to the backend.
- System checks if the fingerprint is authorized → If not, an admin confirmation request is sent.
- Admin approves via MetaMask → A blockchain transaction logs the access attempt.
- Smart Contract verifies the request → If valid, the backend signals the servo motor to unlock the door.
- Real-time web dashboard updates logs → Unauthorized attempts are logged for security.