HF RFID-Based Door Access Control System

Click the image to watch a demo of the control system

Overview

The HF RFID-Based Door Access Control System is designed to provide secure, contactless authentication and physical access control. The system integrates RFID technology with a microcontroller to emulate real-world access control mechanisms used in enterprise and institutional environments.

This project demonstrates end-to-end system design, including hardware integration, communication protocols, and real-time decision logic.

System Design

The system is composed of three primary layers:

1. Sensing Layer

   • RFID reader operating at 13.56 MHz (HF/NFC)
   • Captures unique tag identifiers (UIDs) via inductive coupling

2. Processing Layer

   • Arduino Uno microcontroller
   • Performs UID parsing, validation, and control flow execution

3. Actuation & Feedback Layer

   • Servo motor for physical locking/unlocking
   • LCD display for real-time user feedback

Operational Flow

• A user presents an RFID tag to the reader
• The reader transmits the UID to the microcontroller
• The system performs an authorization check against a predefined dataset
• Based on the result:
  • Authorized: Unlock mechanism is triggered for a fixed duration
  • Unauthorized: Access is denied with no state change

Hardware Implementation

Components

• Arduino Uno R3
• MFRC522 RFID Reader Module
• Servo Motor (locking mechanism)
• I2C-enabled LCD Display
• Breadboard and jumper wiring

Design Considerations

• Power and ground distribution managed via breadboard for stability
• Communication protocols:
  • SPI → RFID reader interface
  • I2C → LCD display interface
  • PWM/Digital Output → Servo control

Software Design

Core Responsibilities

• RFID communication and UID acquisition
• Authorization logic and user mapping
• State management for door control
• User feedback via LCD interface

Data Modeling

• Authorized UIDs stored as structured arrays
• User identity mapping maintained alongside UID data
• Static in-memory dataset, appropriate for prototype scale

Control Flow

The system operates in a continuous polling loop:

1. Prompt user for scan input
2. Detect RFID tag presence
3. Parse UID into normalized hexadecimal format
4. Perform authorization lookup
5. Execute access control logic

Key Behaviors

• Access Granted

  • Servo actuates to open position (~160°)
  • LCD displays user-specific confirmation
  • Automatic re-lock after a fixed interval (5 seconds)

• Access Denied

  • LCD displays denial message
  • No actuation occurs

---

References

Watch RFID door lock access control system | How to make an RFID door lock system using Arduino