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Using an MFRC522 RFID reader

What is an MFRC522 RFID reader

RFID means radio-frequency identification. RFID uses electromagnetic fields to transfer data over short distances. RFID is useful to identify people, to make transactions, etc…

You can use an RFID system to open a door. For example, only the person with the right information on his card is allowed to enter. An RFID system uses tags with each identification and a two-way radio transmitter-receiver as a reader.

rfid.png

Wiring

Caution
You must power this device to 3.3V! This tutorial is based on Arduino UNO, if you are using a different module, please check the specific pinout of that model.

  1. SDA - Digital 10 (SS)
  2. SCK - Digital 13 (SCK)
  3. MOSI - Digital 11 (MOSI)
  4. MISO - Digital 12 (MISO)
  5. IRQ (unconnected)
  6. GND - GND (Ground)
  7. RST - Digital 9
  8. 3.3V to 3.3V (Power)

RFIDwiring.png

Library

We will be using the MFRC522 library. Please see this tutorial to learn how to install libraries.

Getting started

We will be using the example code, DumpInfo, from the library to read an RFID Tag.

#include <SPI.h>
#include <MFRC522.h>

#define RST_PIN         9          // Configurable, see typical pin layout above
#define SS_PIN          10         // Configurable, see typical pin layout above

MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance

void setup() {
	Serial.begin(9600);		// Initialize serial communications with the PC
	while (!Serial);		// Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)
	SPI.begin();			// Init SPI bus
	mfrc522.PCD_Init();		// Init MFRC522
	delay(4);				// Optional delay. Some board do need more time after init to be ready, see Readme
	mfrc522.PCD_DumpVersionToSerial();	// Show details of PCD - MFRC522 Card Reader details
	Serial.println(F("Scan PICC to see UID, SAK, type, and data blocks..."));
}

void loop() {
	// Reset the loop if no new card is present on the sensor/reader. This saves the entire process when idle.
	if ( ! mfrc522.PICC_IsNewCardPresent()) {
		return;
	}

	// Select one of the cards
	if ( ! mfrc522.PICC_ReadCardSerial()) {
		return;
	}

	// Dump debug info about the card; PICC_HaltA() is automatically called
	mfrc522.PICC_DumpToSerial(&(mfrc522.uid));
}

We will be using the example code, DumpInfo, from the library to read an RFID Tag.

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