ESP8266-MFRC522

MFRC522 RFID module connected to ESP8266 (ESP-12) WiFi module

Many thanks to nikxha from the ESP8266 forum (for initial work) and omersiar (for more details of wiring and additional examples)

Requirements

You have to install Arduino IDE 1.6.10 or later. Links are listed below.

• Arduino > Preferences > "Additional Boards Manager URLs:" and add: http://arduino.esp8266.com/stable/package_esp8266com_index.json
• Arduino > Tools > Board > Boards Manager > type in ESP8266 and install the board
• Download MFRC522 library and extract to Arduino library folder or you can use "Library Manager" on the IDE itself to install the MFRC522 library.

Download Links

• Arduino IDE - The development IDE
• ESP8266 Core for Arduino IDE - ESP8266 Core
• MFRC522 Library - MFRC522 RFID Library

Simple Example

Wiring RFID RC522 module

The following table shows the typical pin layout used:

Signal	MFRC522	WeMos D1 mini	NodeMcu	Generic
RST/Reset	RST	D3 [1]	D3 [1]	GPIO-0 [1]
SPI SS	SDA [3]	D8 [2]	D8 [2]	GPIO-15 [2]
SPI MOSI	MOSI	D7	D7	GPIO-13
SPI MISO	MISO	D6	D6	GPIO-12
SPI SCK	SCK	D5	D5	GPIO-14

• [1] (1, 2) Configurable, typically defined as RST_PIN in sketch/program.
• [2] (1, 2) Configurable, typically defined as SS_PIN in sketch/program.
• [3] The SDA pin might be labeled SS on some/older MFRC522 boards

Define RFID module

#include "MFRC522.h"
#define RST_PIN	5 // RST-PIN for RC522 - RFID - SPI - Modul GPIO5 
#define SS_PIN	4 // SDA-PIN for RC522 - RFID - SPI - Modul GPIO4 
MFRC522 mfrc522(SS_PIN, RST_PIN);	// Create MFRC522 instance

Initialize RFID module

void setup() {
  Serial.begin(115200);    // Initialize serial communications
  SPI.begin();	         // Init SPI bus
  mfrc522.PCD_Init();    // Init MFRC522
}

Read RFID tag

void loop() { 
  // Look for new cards
  if ( ! mfrc522.PICC_IsNewCardPresent()) {
    delay(50);
    return;
  }
  // Select one of the cards
  if ( ! mfrc522.PICC_ReadCardSerial()) {
    delay(50);
    return;
  }
  // Show some details of the PICC (that is: the tag/card)
  Serial.print(F("Card UID:"));
  dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size);
  Serial.println();
}

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

More Examples

• ESP RFID - Embedded RFID Access Control Project for MFRC522
• Paralelni Polis RFID Access System - Access Control with Server - Client communication.