WOKWI board-mfrc522 RFID Reader

WOKWI board-mfrc522 RFID Reader

• MFRC522 Basic Reading - Basic RFID card detection with ESP32

 #include <SPI.h>

#include <MFRC522.h>

#define SS_PIN  5

#define RST_PIN 21

MFRC522 rfid(SS_PIN, RST_PIN);

void setup() {

  Serial.begin(115200);

  SPI.begin();

  rfid.PCD_Init();

  Serial.println("MFRC522 Ready");

}

void loop() {

  delay(10);

  if (!rfid.PICC_IsNewCardPresent()) {

    return;

  }

  if (!rfid.PICC_ReadCardSerial()) {

    return;

  }

  Serial.print("UID:");

  for (byte i = 0; i < rfid.uid.size; i++) {

    Serial.print(rfid.uid.uidByte[i] < 0x10 ? ":0" : ":");

    Serial.print(rfid.uid.uidByte[i], HEX);

  }

  Serial.println();

  rfid.PICC_HaltA();

  delay(1000);

}

board-mfrc522 RFID Reader

MFRC522 RFID/NFC reader module with SPI interface for reading 13.56 MHz MIFARE cards and tags.

Pin names

Name	Description
3.3V	Voltage supply (3.3V)
RST	Reset (active low)
GND	Ground
IRQ	Interrupt request (active low)
MISO	SPI data out
MOSI	SPI data in
SCK	SPI clock
SDA	SPI chip select (active low)

Attributes

Name	Description	Default value
uid	Custom UID (for Blue Card only)	""

UID format

The UID can be specified in the following lengths:

• 4 bytes: 01:02:03:04 (MIFARE Classic)
• 7 bytes: 04:11:22:33:44:55:66 (MIFARE Ultralight)

Each byte must be two hexadecimal characters (00-FF), separated by colons.

Card presets

The simulator provides built-in card presets for quick testing. Click on the MFRC522 to open the control panel where you can select a card:

Index	Preset	Color	UID	Card Type
0	Blue Card	Blue	01:02:03:04	MIFARE Classic 1K
1	Green Card	Green	11:22:33:44	MIFARE Classic 1K
2	Yellow Card	Yellow	55:66:77:88	MIFARE Classic 1K
3	Red Card	Red	AA:BB:CC:DD	MIFARE Classic 1K
4	NFC Tag	Gray	04:11:22:33:44:55:66	MIFARE Ultralight
5	Key Fob	Orange	C0:FF:EE:99	MIFARE Mini

The uid attribute only affects the Blue Card (index 0). Other cards always use their preset UIDs. This lets you customize your main card while keeping the others for multi-user testing.