i brought a rfid module which is rc 522 but when i upload the code it is not reading the card even when i upload example code i have returned it 2 times and got it replaced but the same problem may i know the solution

#include "SPI.h" // SPI library
#include "MFRC522.h" // RFID library (https://github.com/miguelbalboa/rfid)

const int pinRST = 9;
const int pinSDA = 10;

MFRC522 mfrc522(pinSDA, pinRST); // Set up mfrc522 on the Arduino

void setup() {
  SPI.begin(); // open SPI connection
  mfrc522.PCD_Init(); // Initialize Proximity Coupling Device (PCD)
  Serial.begin(9600); // open serial connection

void loop() {
  if (mfrc522.PICC_IsNewCardPresent()) { // (true, if RFID tag/card is present ) PICC = Proximity Integrated Circuit Card
    if(mfrc522.PICC_ReadCardSerial()) { // true, if RFID tag/card was read
      Serial.print("RFID TAG ID:");
      for (byte i = 0; i < mfrc522.uid.size; ++i) { // read id (in parts)
        Serial.print(mfrc522.uid.uidByte[i], HEX); // print id as hex values
        Serial.print(" "); // add space between hex blocks to increase readability
      Serial.println(); // Print out of id is complete.

this is one of the many codes i used

  • 1
    What gets printed? You have a lot of serial prints there, can you please edit the question and share what you see?
    – Nick Gammon
    Nov 8, 2021 at 6:17
  • 1
    i just see nothing Nov 8, 2021 at 14:50
  • Possibly you have wired it incorrectly. Without seeing any photos, links to the module you bought, or schematics, it is very hard, if not impossible, to say.
    – Nick Gammon
    Nov 9, 2021 at 6:15
  • SDA 10, SCK 13, MOSI 11, MISO 12, IRQ UNUSED, GND GND, RST 9, 3.3V 3.3V, i dont feel they are wrong Nov 9, 2021 at 14:05


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.