How to Make an RFID Door Lock System using Arduino

Learn how to build an RFID-based door lock system using Arduino to enhance security with contactless access control.

1. An Easy Approach to Door
Locking System
Author
Yogeshwaran

2. RFID Door Lock System
Using Arduino
An RFID (Radio Frequency
Identification) door lock system
allows access control using RFID
cards or tags.
When an authorized tag is scanned,
the door unlocks, and for
unauthorized tags, access is denied.
This system is commonly used in
homes, offices, and restricted areas
to enhance security.

3. Components &
Circuit Design
Key Components:
Arduino UNO – The main controller.
RFID Module (RC522) – Reads the RFID
tags.
Servo Motor – Controls the locking
mechanism.
Buzzer – Alerts on unauthorized access.
16x2 LCD Display (Optional) – Displays
status messages.
Power Supply & Jumper Wires – For
connections.
Once these components are gathered,
the next step is wiring them together
following the circuit diagram.

4. Assembly & Wiring
The RFID module (RC522) connects to
Arduino using SPI protocol.
The servo motor is connected to control
the lock.
The buzzer sounds an alarm if an
unauthorized card is scanned.
Power supply setup to keep the system
running.
Key Connections:
RFID Module → SPI pins on Arduino (SDA,
SCK, MOSI, MISO).
Servo Motor → PWM pin on Arduino.
Buzzer → Digital pin for sound alerts.

5. Working Principle
Scanning the RFID Tag:
When an RFID card/tag is brought
near the RFID module, it reads the
unique ID (UID).
Checking Authentication:
The Arduino compares the UID
with a predefined list of
authorized IDs.
Unlocking the Door:
If the UID matches, the servo
motor rotates to unlock the door.
Access Denied Alert:
If the UID is unauthorized, the
buzzer beeps, and the door
remains locked.

6. For a more in-depth tutorial,
check out this article:
https://circuitdigest.com/microcontroll
er-projects/how-to-build-a-speed-
sensor-using-arduino
www.circuitdigest.com
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