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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
| 1 | × | ESP-WROOM-32 Dev Module | |
| 1 | × | USB Cable Type-C | |
| 1 | × | RFID/NFC RC522 Kit (reader + tags) | |
| 1 | × | RFID Key Fob | |
| 1 | × | Breadboard | |
| 1 | × | Jumper Wires | |
| 1 | × | (Optional) DC Power Jack | |
| 1 | × | (Recommended) ESP32 Screw Terminal Adapter |
Or you can buy the following sensor kit:
| 1 | × | DIYables Sensor Kit 30 types, 69 units |
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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
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) | |
| GND pin | → GND |
| RST pin | → (11) GPIO27 |
| VCC pin | → 3.3V |
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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