The RFID RC522 is a low-cost RFID reader/writer module that operates at a frequency of 13.56 MHz. It is widely used for reading RFID tags and cards, enabling wireless communication in a variety of applications. This module is based on the MFRC522 IC and supports ISO/IEC 14443 Type A cards. Its compact size, low power consumption, and ease of integration make it a popular choice for projects involving access control, inventory management, attendance systems, and identification systems.
This circuit is designed to read RFID tags using the RFID-RC522 module, display information on an I2C LCD screen, and accept user input via a 4x4 membrane matrix keypad. It is controlled by an Arduino UNO, which is powered by a 3xAA battery pack, and communicates with the RFID module and LCD screen using SPI and I2C protocols, respectively.
Open Project in Cirkit Designer
This circuit integrates an Arduino UNO with an RFID-RC522 module to enable RFID-based identification. The Arduino provides power and SPI communication to the RFID module, allowing it to read RFID tags and potentially perform actions based on the tag data.
Open Project in Cirkit Designer
This circuit interfaces an RFID-RC522 module with an Arduino UNO. The Arduino UNO provides power and handles communication with the RFID module via SPI protocol, enabling the system to read RFID tags.
Open Project in Cirkit Designer
This circuit integrates an Arduino UNO with an RFID-RC522 module and an HC-05 Bluetooth module. The Arduino UNO reads RFID tags via the RFID-RC522 and communicates the data wirelessly through the HC-05 Bluetooth module.
Open Project in Cirkit DesignerBelow are the key technical details and pin configuration of the RFID RC522 module:
The RFID RC522 module has 8 pins, as described in the table below:
| Pin | Name | Description |
|---|---|---|
| 1 | VCC | Power supply input (3.3V). Can be connected to 5V with a level shifter. |
| 2 | RST | Reset pin. Active LOW. Used to reset the module. |
| 3 | GND | Ground connection. |
| 4 | IRQ | Interrupt pin. Can be used to signal events (optional). |
| 5 | MISO/SCL/TX | SPI MISO (Master In Slave Out), I2C clock (SCL), or UART TX (default: SPI MISO). |
| 6 | MOSI/SDA/RX | SPI MOSI (Master Out Slave In), I2C data (SDA), or UART RX (default: SPI MOSI). |
| 7 | SCK | SPI clock input. |
| 8 | NSS/SDA | SPI chip select (NSS) or I2C address select (SDA). |
#include <SPI.h>
#include <MFRC522.h>
// Define pins for the RC522 module
#define RST_PIN 9 // Reset pin connected to D9
#define SS_PIN 10 // Slave Select pin connected to D10
MFRC522 rfid(SS_PIN, RST_PIN); // Create an instance of the MFRC522 class
void setup() {
Serial.begin(9600); // Initialize serial communication
SPI.begin(); // Initialize SPI bus
rfid.PCD_Init(); // Initialize the RC522 module
Serial.println("Place your RFID card near the reader...");
}
void loop() {
// Check if a new card is present
if (!rfid.PICC_IsNewCardPresent()) {
return; // Exit if no card is detected
}
// Check if the card can be read
if (!rfid.PICC_ReadCardSerial()) {
return; // Exit if the card cannot be read
}
// Print the UID of the card
Serial.print("Card UID: ");
for (byte i = 0; i < rfid.uid.size; i++) {
Serial.print(rfid.uid.uidByte[i], HEX); // Print each byte in hexadecimal
Serial.print(" ");
}
Serial.println();
// Halt the card to stop communication
rfid.PICC_HaltA();
}
Module Not Responding:
Card Not Detected:
UID Not Displayed:
Can the RC522 module write data to RFID tags? Yes, the RC522 can write data to compatible RFID tags. Refer to the MFRC522 library examples for writing data.
Can I use the RC522 with a 5V microcontroller? Yes, but you must use level shifters for the SPI pins to avoid damaging the module.
What is the maximum range of the RC522 module? The maximum range is approximately 5 cm, depending on the tag and environmental conditions.