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ESP32 - RFID/NFC
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
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links in this section are Amazon affiliate links, meaning we may earn a commission at no additional cost to you if you make a purchase through them. Additionally, some links direct you to products from our own brand, DIYables.
Introduction to 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.
- 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.
※ NOTE THAT:
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
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) | |
| GND pin | → GND |
| RST pin | → (11) GPIO27 |
| VCC pin | → 3.3V |
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.
ESP32 RFID/NFC Code
/*
* This ESP32 code is created by esp32io.com
*
* This ESP32 code is released in the public domain
*
* For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-rfid-nfc
*/
#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.
- 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
- Tap several RFID/NFC tags on RFID-RC522 module
- See the UID printed on Serial Monitor
COM6
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
Clear output
9600 baud
Newline
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