Tutorial: How to use MFRC522 RFID module using Arduino

Sep 1, 2020 · 5 min read · Arduino RFID Arduino RFID projects Arduino RFID tags MFRC522 RC522 ·

Introduction

I am sharing this tutorial so someone might benefited from it somehow.

I am fascinated with RFIDs capability, though this technology has been around many years before me. Now that I have this module, I tried to play with it.

The RFID tags can contain 1 kilo bytes of data, amazing right?

Circuit Diagram

Video Demonstration

Call To Action

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Source Code

1. Read and Write to RFID tags:

  1 #include <SPI.h>  
  2 #include <MFRC522.h>  
  3 #define RST_PIN     9      // Configurable, see typical pin layout above  
  4 #define SS_PIN     10     // Configurable, see typical pin layout above  
  5 MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance.  
  6 MFRC522::MIFARE_Key key;  
  7   // In this sample we use the second sector,  
  8   // that is: sector #1, covering block #4 up to and including block #7  
  9   byte sector     = 1;  
 10   byte blockAddr   = 4;  
 11   byte dataBlock[]  = {  
 12     0x01, 0x02, 0x03, 0x04,  
 13     0x05, 0x06, 0x07, 0x08,  
 14     0x09, 0x0a, 0xff, 0x0b,  
 15     0x0c, 0x0d, 0x0e, 0x0f  
 16   };  
 17 //  byte dataBlock[]  = {  
 18 //    0x00, 0x00, 0x00, 0x00,  
 19 //    0x00, 0x00, 0x00, 0x00,  
 20 //    0x00, 0x00, 0x00, 0x00,  
 21 //    0x00, 0x00, 0x00, 0x00   
 22 //  };  
 23   byte trailerBlock  = 7;  
 24   MFRC522::StatusCode status;  
 25   byte buffer[18];  
 26   byte size = sizeof(buffer);  
 27 /**  
 28  * Initialize.  
 29  */  
 30 void setup() {  
 31   Serial.begin(9600); // Initialize serial communications with the PC  
 32   while (!Serial);  // Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)  
 33   SPI.begin();    // Init SPI bus  
 34   mfrc522.PCD_Init(); // Init MFRC522 card  
 35   // Prepare the key (used both as key A and as key B)  
 36   // using FFFFFFFFFFFFh which is the default at chip delivery from the factory  
 37   for (byte i = 0; i < 6; i++) {  
 38     key.keyByte[i] = 0xFF;  
 39   }  
 40 //  Serial.println(F("Scan a MIFARE Classic PICC to demonstrate read and write."));  
 41 //  Serial.print(F("Using key (for A and B):"));  
 42 //  dump_byte_array(key.keyByte, MFRC522::MF_KEY_SIZE);  
 43 //  Serial.println();  
 44 //  
 45 //  Serial.println(F("BEWARE: Data will be written to the PICC, in sector #1"));  
 46   Serial.println("Setup Done");  
 47 }  
 48 /**  
 49  * Main loop.  
 50  */  
 51 void loop() {  
 52   // Reset the loop if no new card present on the sensor/reader. This saves the entire process when idle.  
 53   if ( ! mfrc522.PICC_IsNewCardPresent())  
 54     return;  
 55   // Select one of the cards  
 56   if ( ! mfrc522.PICC_ReadCardSerial())  
 57     return;  
 58   // Show some details of the PICC (that is: the tag/card)  
 59   Serial.print(F("Card UID:"));  
 60   dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size);  
 61   Serial.println();  
 62   Serial.print(F("PICC type: "));  
 63   MFRC522::PICC_Type piccType = mfrc522.PICC_GetType(mfrc522.uid.sak);  
 64   Serial.println(mfrc522.PICC_GetTypeName(piccType));  
 65   // Check for compatibility  
 66   if (  piccType != MFRC522::PICC_TYPE_MIFARE_MINI  
 67     && piccType != MFRC522::PICC_TYPE_MIFARE_1K  
 68     && piccType != MFRC522::PICC_TYPE_MIFARE_4K) {  
 69     Serial.println(F("This sample only works with MIFARE Classic cards."));  
 70     return;  
 71   }  
 72   Serial.println("");  
 73   // Authenticate using key A  
 74   //Serial.println(F("Authenticating using key A..."));  
 75   status = (MFRC522::StatusCode) mfrc522.PCD_Authenticate(MFRC522::PICC_CMD_MF_AUTH_KEY_A, trailerBlock, &key, &(mfrc522.uid));  
 76   if (status != MFRC522::STATUS_OK) {  
 77     Serial.print(F("PCD_Authenticate() failed: "));  
 78     Serial.println(mfrc522.GetStatusCodeName(status));  
 79     return;  
 80   }  
 81   // Read data from the block  
 82   Serial.print(F("Reading data from block ")); Serial.print(blockAddr);  
 83   Serial.println(F(" ..."));  
 84   status = (MFRC522::StatusCode) mfrc522.MIFARE_Read(blockAddr, buffer, &size);  
 85   if (status != MFRC522::STATUS_OK) {  
 86     Serial.print(F("MIFARE_Read() failed: "));  
 87     Serial.println(mfrc522.GetStatusCodeName(status));  
 88   }  
 89   Serial.print(F("Data in block ")); Serial.print(blockAddr); Serial.println(F(":"));  
 90   dump_byte_array(buffer, 16); Serial.println();  
 91   Serial.println();  
 92   // Write data to the block  
 93   Serial.print(F("Writing data into block ")); Serial.print(blockAddr);  
 94   Serial.println(F(" ..."));  
 95   dump_byte_array(dataBlock, 16); Serial.println();  
 96   status = (MFRC522::StatusCode) mfrc522.MIFARE_Write(blockAddr, dataBlock, 16);  
 97   if (status != MFRC522::STATUS_OK) {  
 98     Serial.print(F("MIFARE_Write() failed: "));  
 99     Serial.println(mfrc522.GetStatusCodeName(status));  
100   }  
101   Serial.println();  
102   // Read data from the block (again, should now be what we have written)  
103   Serial.print(F("Reading data from block ")); Serial.print(blockAddr);  
104   Serial.println(F(" ..."));  
105   status = (MFRC522::StatusCode) mfrc522.MIFARE_Read(blockAddr, buffer, &size);  
106   if (status != MFRC522::STATUS_OK) {  
107     Serial.print(F("MIFARE_Read() failed: "));  
108     Serial.println(mfrc522.GetStatusCodeName(status));  
109   }  
110   Serial.print(F("Data in block ")); Serial.print(blockAddr); Serial.println(F(":"));  
111   dump_byte_array(buffer, 16);   
112   Serial.println();  
113   // Halt PICC  
114   mfrc522.PICC_HaltA();  
115   // Stop encryption on PCD  
116   mfrc522.PCD_StopCrypto1();  
117 }  
118 /**  
119  * Helper routine to dump a byte array as hex values to Serial.  
120  */  
121 void dump_byte_array(byte *buffer, byte bufferSize) {  
122   for (byte i = 0; i < bufferSize; i++) {  
123     Serial.print(buffer[i] < 0x10 ? " 0" : " ");  
124     Serial.print(buffer[i], HEX);  
125   }  
126 }

2. Sample Application: RFID Security Key:

 1 #include <SPI.h>  
 2 #include <MFRC522.h>  
 3 #define SS_PIN 10  
 4 #define RST_PIN 9  
 5 MFRC522 mfrc522(SS_PIN, RST_PIN);  
 6 void setup()   
 7 {  
 8  Serial.begin(9600);  
 9  SPI.begin();  
10  mfrc522.PCD_Init();  
11  Serial.println("Welcome, scan your card to enter");  
12  Serial.println();  
13 }  
14 void loop()   
15 {  
16  // Check for new RFID  
17  if ( ! mfrc522.PICC_IsNewCardPresent())   
18  {  
19   return;  
20  }  
21  // If the card use is not compatible,  
22  // do not continue  
23  if ( ! mfrc522.PICC_ReadCardSerial())   
24  {  
25   Serial.println("Access Denied");  
26   return;  
27  }  
28  // Process the RFID  
29  Serial.print("UID tag :");  
30  String content= "";  
31  byte letter;  
32  for (byte i = 0; i < mfrc522.uid.size; i++)   
33  {  
34    Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");  
35    Serial.print(mfrc522.uid.uidByte[i], HEX);  
36    content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));  
37    content.concat(String(mfrc522.uid.uidByte[i], HEX));  
38  }  
39  Serial.println();  
40  Serial.print("Message : ");  
41  content.toUpperCase();  
42  // Verify if the card is in the record  
43  if ( (content.substring(1) == "E4 6B 0B 2A") ||   
44     (content.substring(1) == "E7 45 8E 7A"))  {  
45   Serial.println(" Access granted.");  
46   Serial.println();  
47   delay(3000);  
48  } else {  
49   Serial.println(" Access denied");  
50   delay(3000);  
51  }  
52 }