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Interfacing RFID Sensor Module with Arduino

RFID Sensor Module

An RFID Sensor Module is used for reading data stored on RFID tags. It’s widely used in access control systems, inventory tracking, and smart automation projects.

Working Principle of RFID Sensor Module

The RFID reader emits a radio frequency field that powers the passive RFID tag. Once powered, the tag sends back its unique ID, which the reader captures and transmits to the Arduino.

Types of RFID Modules

Passive RFID Module

  • Reader emits RF field to activate the tag.
  • Tag reflects its ID signal back to the reader.
  • Reader sends data to the Arduino.

Active RFID Module

  • Battery-powered tag transmits its signal independently.
  • Reader picks up the tag’s ID.
  • Arduino processes the received ID data.

Requirements

1. Arduino Uno or compatible board

2. RC522 RFID Reader Module

3. RFID Tags or Cards

4. Jumper wires

Pin Configuration of RFID Module

RC522 RFID Module

  • VCC: Connect to 3.3V on Arduino.
  • RST: Connect to digital pin (e.g., D9).
  • GND: Connect to GND on Arduino.
  • MISO: Connect to digital pin (e.g., D12).
  • MOSI: Connect to digital pin (e.g., D11).
  • SCK: Connect to digital pin (e.g., D13).
  • SDA: Connect to digital pin (e.g., D10).

Wiring the RFID Module to Arduino

Connect the RC522 module to the Arduino using SPI interface pins. Ensure you power it with 3.3V, not 5V, to avoid damage. Wire the SDA, SCK, MOSI, MISO, RST, and GND pins to their corresponding Arduino pins.

Algorithm

  1. Initialize Components

    • Connect all RFID module pins to the respective Arduino pins.
    • Include the necessary RFID libraries in your code.

  2. Write the Code

    • Include the MFRC522 library.
    • Initialize SPI communication and RFID module in setup().
    • In loop(), check for the presence of a tag and read the UID.

  3. Display or Compare Tag IDs

    • Print tag ID to the serial monitor.
    • Compare the tag ID with predefined IDs to trigger actions.

  4. Test the System

    • Upload the code to Arduino.
    • Present different RFID tags and observe the output.

Arduino Code

1#include <SPI.h>
2#include <MFRC522.h>
3
4#define SS_PIN 10   // SDA pin on RC522
5#define RST_PIN 9   // RST pin on RC522
6
7MFRC522 rfid(SS_PIN, RST_PIN);  // Create MFRC522 instance
8
9void setup() {
10  Serial.begin(9600);
11  SPI.begin();        // Start SPI bus
12  rfid.PCD_Init();    // Initialize RFID module
13  Serial.println("Place your RFID card/tag near the reader...");
14}
15
16void loop() {
17  // Check for new cards
18  if (!rfid.PICC_IsNewCardPresent()) {
19    return;
20  }
21
22  // Select the card
23  if (!rfid.PICC_ReadCardSerial()) {
24    return;
25  }
26
27  // Print UID
28  Serial.print("UID Tag: ");
29  for (byte i = 0; i < rfid.uid.size; i++) {
30    Serial.print(rfid.uid.uidByte[i] < 0x10 ? " 0" : " ");
31    Serial.print(rfid.uid.uidByte[i], HEX);
32  }
33  Serial.println();
34
35  // Halt communication with card
36  rfid.PICC_HaltA();
37}
38

Applications of RFID Modules

  • Secure access control systems
  • Library and inventory tracking
  • Employee or student attendance systems
  • Automated parking management
  • Pet or livestock identification
  • Smart home automation

Conclusion

Using an RFID Sensor Module with Arduino enables secure and automated identification systems. With just a few connections and a simple code, RFID technology can add a powerful layer of functionality to your Arduino projects.