RFID-RC522的使用[通俗易懂]

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射频识别技术RFID（Radio Frequency Identification），又称为电子标签、无线射频识别，是一种非接触式的自动识别技术，通过无线电讯号识别特定目标并读写相关数据而无需识别系统与特定目标之间建立机械或光学接触。可用于识别高速运动物体并可同时识别多个标签，过程中无需人工干预，操作快捷方便。可工作于各种环境，实现对各类物体或设备（人员、物品）在不同状态（移动、静止或恶劣环境）下的自动识别和管理。

RFID系统主要由应答器、阅读器和高层应用组成，其中的应答器包括集成电路芯片。阅读器用于产生射频载波与应答器进行信息交互。高层应用包括信息的管理和决策。

接线

Arduino Uno     <——>   RFID-RC522

10            <——>                SDA

13            <——>                SCK

11           <——>                MOSI

12            <——>                MISO

–null–     <——>                IRQ (IRQ是中断才用到的此处没有用到可以不接)

GND       <——>                GND

9              <——>                RST

3.3V        <——>               3.3V

需要下载有关的第三方库

实现读取卡片信息的代码：

/*
 * --------------------------------------------------------------------------------------------------------------------
 * Example sketch/program showing how to read new NUID from a PICC to serial.
 * --------------------------------------------------------------------------------------------------------------------
 * This is a MFRC522 library example; for further details and other examples see: https://github.com/miguelbalboa/rfid
 * 
 * Example sketch/program showing how to the read data from a PICC (that is: a RFID Tag or Card) using a MFRC522 based RFID
 * Reader on the Arduino SPI interface.
 * 
 * When the Arduino and the MFRC522 module are connected (see the pin layout below), load this sketch into Arduino IDE
 * then verify/compile and upload it. To see the output: use Tools, Serial Monitor of the IDE (hit Ctrl+Shft+M). When
 * you present a PICC (that is: a RFID Tag or Card) at reading distance of the MFRC522 Reader/PCD, the serial output
 * will show the type, and the NUID if a new card has been detected. Note: you may see "Timeout in communication" messages
 * when removing the PICC from reading distance too early.
 * 
 * @license Released into the public domain.
 * 
 * Typical pin layout used:
 * -----------------------------------------------------------------------------------------
 *             MFRC522      Arduino       Arduino   Arduino    Arduino          Arduino
 *             Reader/PCD   Uno/101       Mega      Nano v3    Leonardo/Micro   Pro Micro
 * Signal      Pin          Pin           Pin       Pin        Pin              Pin
 * -----------------------------------------------------------------------------------------
 * RST/Reset   RST          9             5         D9         RESET/ICSP-5     RST
 * SPI SS      SDA(SS)      10            53        D10        10               10
 * SPI MOSI    MOSI         11 / ICSP-4   51        D11        ICSP-4           16
 * SPI MISO    MISO         12 / ICSP-1   50        D12        ICSP-1           14
 * SPI SCK     SCK          13 / ICSP-3   52        D13        ICSP-3           15
 */
#include <SPI.h>
#include <MFRC522.h>
#define SS_PIN 10
#define RST_PIN 9
 
MFRC522 rfid(SS_PIN, RST_PIN); // Instance of the class
MFRC522::MIFARE_Key key; 
// Init array that will store new NUID 
byte nuidPICC[4];
void setup() { 
  Serial.begin(9600);
  SPI.begin(); // Init SPI bus
  rfid.PCD_Init(); // Init MFRC522 
  for (byte i = 0; i < 6; i++) {
    key.keyByte[i] = 0xFF;
  }
  Serial.println(F("This code scan the MIFARE Classsic NUID."));
  Serial.print(F("Using the following key:"));
  printHex(key.keyByte, MFRC522::MF_KEY_SIZE);
}
 
void loop() {
  // Reset the loop if no new card present on the sensor/reader. This saves the entire process when idle.
  if ( ! rfid.PICC_IsNewCardPresent())
    return;
  // Verify if the NUID has been readed
  if ( ! rfid.PICC_ReadCardSerial())
    return;
  Serial.print(F("PICC type: "));
  MFRC522::PICC_Type piccType = rfid.PICC_GetType(rfid.uid.sak);
  Serial.println(rfid.PICC_GetTypeName(piccType));
  // Check is the PICC of Classic MIFARE type
  if (piccType != MFRC522::PICC_TYPE_MIFARE_MINI &&  
    piccType != MFRC522::PICC_TYPE_MIFARE_1K &&
    piccType != MFRC522::PICC_TYPE_MIFARE_4K) {
    Serial.println(F("Your tag is not of type MIFARE Classic."));
    return;
  }
  if (rfid.uid.uidByte[0] != nuidPICC[0] || 
    rfid.uid.uidByte[1] != nuidPICC[1] || 
    rfid.uid.uidByte[2] != nuidPICC[2] || 
    rfid.uid.uidByte[3] != nuidPICC[3] ) {
    Serial.println(F("A new card has been detected."));
    // Store NUID into nuidPICC array
    for (byte i = 0; i < 4; i++) {
      nuidPICC[i] = rfid.uid.uidByte[i];
    }
   
    Serial.println(F("The NUID tag is:"));
    Serial.print(F("In hex: "));
    printHex(rfid.uid.uidByte, rfid.uid.size);
    Serial.println();
    Serial.print(F("In dec: "));
    printDec(rfid.uid.uidByte, rfid.uid.size);
    Serial.println();
  }
  else Serial.println(F("Card read previously."));
  // Halt PICC
  rfid.PICC_HaltA();
  // Stop encryption on PCD
  rfid.PCD_StopCrypto1();
}

/**
 * Helper routine to dump a byte array as hex values to Serial. 
 */
void printHex(byte *buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? " 0" : " ");
    Serial.print(buffer[i], HEX);
  }
}
/**
 * Helper routine to dump a byte array as dec values to Serial.
 */
void printDec(byte *buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? " 0" : " ");
    Serial.print(buffer[i], DEC);
  }
}

两种不同形状的卡片所对应的识别结果：