This tutorial instructs you how to use ESP32 withRC522 RFID/NFC reader to read the information from RFID/NFC tag.

Hardware Used In This Tutorial

1×ESP-WROOM-32 Dev Module
1×USB Cable Type-C
1×RFID/NFC RC522 Kit (reader + tags)
1×RFID Key Fob
1×Jumper Wires
1×(Optional) DC Power Jack
1×(Recommended) ESP32 Screw Terminal Adapter

Or you can buy the following sensor kits:

1×DIYables Sensor Kit (30 sensors/displays)
1×DIYables Sensor Kit (18 sensors/displays)
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Introduction to RFID-RC522 Module


RFID-RC522 module Pinout

The RFID-RC522 module has 8 pins, some pins are shared among three communication interfaces: SPI, I2C, UART. At a time, only one communication mode can be used. The pin are:

  • GND pin: connect this pin to GND (0V)
  • VCC pin: connect this pin to VCC (3.3)
  • RST pin: is a pin for reset and power-down. When this pin goes low, hard power-down is enabled. On the rising edge, the module is reset.
  • IRQ pin: is an interrupt pin that can alert the ESP32 when RFID tag comes into its detection range.
  • MISO/SCL/TX pin: works as:
    • MISO pin if SPI interface is enabled
    • SCL pin if I2C interface is enabled
    • TX pin if UART interface is enabled.
  • MOSI pin: works as MOSI if SPI interface is enabled.
  • SCK pin: works as SCK if SPI interface is enabled
  • SS/SDA/RX pin: works as:
    • SS pin if SPI interface is enabled
    • SDA pin when I2C interface is enabled
    • RX pin when UART interface is enabled.

    ※ NOTE THAT:

    • The pins order can vary according to manufacturers. ALWAYS use the labels printed on the module. The above image shows the pinout of the modules from DIYables manufacturer.
    • The RFID-RC522 module works with 3.3V. Do not connect the RFID-RC522 module's VCC pin to 5V. 5V can burn the RFID-RC522 module.
    • This tutorial uses SPI interface for communication between ESP32 and RFID-RC522 module.

Wiring Diagram

ESP32 RFID RC522 wiring diagram

This image is created using Fritzing. Click to enlarge image

If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.

The wiring table between RFID/NFC RC522 Module and ESP32

RFID/NFC RC522 Module ESP32
SS pin → (29) GPIO5
SCK pin → (30) GPIO18
MOSI pin → (37) GPIO23
MISO pin → (31) GPIO19
IRQ pin(not connected)
RST pin → (11) GPIO27
VCC pin → 3.3V


/* * This ESP32 code is created by * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit */ #include <SPI.h> #include <MFRC522.h> #define SS_PIN 5 // ESP32 pin GPIO5 #define RST_PIN 27 // ESP32 pin GPIO27 MFRC522 rfid(SS_PIN, RST_PIN); void setup() { Serial.begin(9600); SPI.begin(); // init SPI bus rfid.PCD_Init(); // init MFRC522 Serial.println("Tap an RFID/NFC tag on the RFID-RC522 reader"); } void loop() { if (rfid.PICC_IsNewCardPresent()) { // new tag is available if (rfid.PICC_ReadCardSerial()) { // NUID has been readed MFRC522::PICC_Type piccType = rfid.PICC_GetType(rfid.uid.sak); Serial.print("RFID/NFC Tag Type: "); Serial.println(rfid.PICC_GetTypeName(piccType)); // print UID in Serial Monitor in the hex format Serial.print("UID:"); for (int 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(); // halt PICC rfid.PCD_StopCrypto1(); // stop encryption on PCD } } }

Quick Instructions

  • If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
  • Click to the Libraries icon on the left bar of the Arduino IDE.
  • Type “MFRC522” on the search box, then look for the library by GithubCommunity
  • Install the library by clicking on Install button.
ESP32 MFRC522 library
  • Copy the above code and paste it to Arduino IDE.
  • Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
  • Open Serial Monitor on Arduino IDE
How to open serial monitor on Arduino IDE
  • Tap several RFID/NFC tags on RFID-RC522 module
  • See the UID printed on Serial Monitor
Tap an RFID/NFC tag on the RFID-RC522 reader RFID/NFC tag Type: MIFARE 1KB UID: 2B B8 59 B1 RFID/NFC tag Type: MIFARE Ultralight or Ultralight C UID: 15 75 46 7A 2C 5B 7E
Autoscroll Show timestamp
Clear output
9600 baud  

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