How to Read RFID Tags with Arduino

Hello, tech wizards! Are you ready to uncover the secrets of RFID and explore the power of Unique Identifiers (UIDs)? Today, we’re taking a deep dive into the fascinating world of Arduino and RFID technology. We’ll learn how to use an Arduino to read the UID (Unique Identifier) from RFID tags and discover the incredible uses and benefits of UIDs. Let the adventure begin!

What You Need

Before we embark on our RFID and UID journey, let’s make sure we have all the necessary tools ready to roll:

1Arduino Board (such as Arduino Uno).
2RC522 RFID Module (Don’t worry; we’ll explain this nifty device shortly).
3RFID Tags or Cards (These are our magical keys with UIDs waiting to be read).
4Breadboard and Jumper Wires (To make the connections a breeze).

Setting Up the Hardware

Let’s kick things off by connecting our RFID module to the Arduino. Don’t worry; it’s easier than you might think!

  • SDA to digital pin 10.
  • SCK to digital pin 13.
  • MOSI to digital pin 11.
  • MISO to digital pin 12.
  • IRQ to any digital pin (Not Using).
  • RST to digital pin 9.
  • GND to the Arduino’s ground.
  • 3.3V to the Arduino’s 3.3V power.

Circuit Diagram

"Learn How to Read RFID tags with step-by-step instructions and explore the fascinating world of RFID technology."

Writing the Arduino Code

Download the Library MFRC522

Consider these additional suggestions if the current solution is not effective.

Now, it’s time to weave some coding magic! This code will enable our Arduino to read the UID (Unique Identifier) from the RFID tag.

#include <SPI.h>
#include <MFRC522.h>

#define SS_PIN 10
#define RST_PIN 9
 
MFRC522 rfid(SS_PIN, RST_PIN); // Instance of the class

MFRC522::MIFARE_Key key; 

// Init array that will store new NUID 
byte nuidPICC[4];

void setup() { 
  Serial.begin(9600);
  SPI.begin(); // Init SPI bus
  rfid.PCD_Init(); // Init MFRC522 

  for (byte i = 0; i < 6; i++) {
    key.keyByte[i] = 0xFF;
  }

  Serial.println(F("This code scan the MIFARE Classsic NUID."));
  Serial.print(F("Using the following key:"));
  printHex(key.keyByte, MFRC522::MF_KEY_SIZE);
}
 
void loop() {

  // Look for new cards
  if ( ! rfid.PICC_IsNewCardPresent())
    return;

  // Verify if the NUID has been readed
  if ( ! rfid.PICC_ReadCardSerial())
    return;

  Serial.print(F("PICC type: "));
  MFRC522::PICC_Type piccType = rfid.PICC_GetType(rfid.uid.sak);
  Serial.println(rfid.PICC_GetTypeName(piccType));

  // Check is the PICC of Classic MIFARE type
  if (piccType != MFRC522::PICC_TYPE_MIFARE_MINI &&  
    piccType != MFRC522::PICC_TYPE_MIFARE_1K &&
    piccType != MFRC522::PICC_TYPE_MIFARE_4K) {
    Serial.println(F("Your tag is not of type MIFARE Classic."));
    return;
  }

  if (rfid.uid.uidByte[0] != nuidPICC[0] || 
    rfid.uid.uidByte[1] != nuidPICC[1] || 
    rfid.uid.uidByte[2] != nuidPICC[2] || 
    rfid.uid.uidByte[3] != nuidPICC[3] ) {
    Serial.println(F("A new card has been detected."));

    // Store NUID into nuidPICC array
    for (byte i = 0; i < 4; i++) {
      nuidPICC[i] = rfid.uid.uidByte[i];
    }
   
    Serial.println(F("The NUID tag is:"));
    Serial.print(F("In hex: "));
    printHex(rfid.uid.uidByte, rfid.uid.size);
    Serial.println();
    Serial.print(F("In dec: "));
    printDec(rfid.uid.uidByte, rfid.uid.size);
    Serial.println();
  }
  else Serial.println(F("Card read previously."));

  // Halt PICC
  rfid.PICC_HaltA();

  // Stop encryption on PCD
  rfid.PCD_StopCrypto1();
}


/**
 * Helper routine to dump a byte array as hex values to Serial. 
 */
void printHex(byte *buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? " 0" : " ");
    Serial.print(buffer[i], HEX);
  }
}

/**
 * Helper routine to dump a byte array as dec values to Serial.
 */
void printDec(byte *buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? " 0" : " ");
    Serial.print(buffer[i], DEC);
  }
}

Unlocking the Magic of UID

But what exactly is UID, and why is it so important?

UID (Unique Identifier) is like a secret code, a fingerprint, or a special name that belongs to each RFID tag or card. It’s a way for the RFID system to tell one tag apart from all the others in the world.

The Power and Benefits of UID

Now, let’s delve into why UID is a game-changer:

  1. Uniqueness: Just like your name is one-of-a-kind, each UID is unique. This means no two RFID tags share the same code. It’s like having a magical name that belongs only to you!
  2. Enhanced Security: UID is your RFID tag’s secret key. It ensures that only authorized tags with the correct UID can gain access. Unauthorized or cloned tags with different UIDs are kept at bay.
  3. Efficiency: UID works like a speed booster. It makes processes like inventory management and access control lightning fast. No need for manual data entry or barcode scanning.
  4. Accuracy: UID eliminates errors. With electronic reading, there’s minimal room for mistakes, making data more accurate and reliable.

How UIDs are Stored in RFID Cards

Inside an RFID card, there’s a tiny chip or integrated circuit (IC). This chip has a special memory bank called the “UID bank,” where the unique code is stored during manufacturing. When an RFID reader sends out a signal, the chip wakes up and shares its UID, allowing the reader to identify the card.

In simple terms, UIDs are like secret codes stored in the heart of RFID cards, making each card unique and indispensable.

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Conclusion: Unleash the RFID Magic

Congratulations! You’ve unlocked the secrets of UID & Learned How to Read RFID Tags, the Unique Identifier, and learned how to make Arduino read it from RFID tags. Armed with this knowledge, you can embark on exciting projects like creating secret doors or organizing thrilling treasure hunts. RFID technology, powered by UID, is your ticket to a world of endless possibilities. Keep exploring, and let your RFID adventures begin!

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