Elechouse PN532 NFC Module V3 for Arduino etc.

  • @OniMoxy Try to connect the VCC to the 3.3V.
    It fixed the problem for me.

  • Community Helper

    Did you change the switches? the board has a different default mode

  • Community Helper

    @Lafunamor's suggestion first, make sure it's reading in the right mode and your sketch is setting up for that mode correctly. Then mess with the input voltage if you need to as per @Nairod785's suggestion.

  • I have set the switches for I2C mode.
    Connecting to 3.3V instead of 5V didn't help.

    Funny thing is if I disconnect VCC shortly while the Arduino sketch is running setup() then it works!
    It skips getting the firmware version, goes into loop() mode and waits for a card.
    I place a card and it detects it!

    I think there is something wrong with the PN532_I2C library.

    I also found that it does work with the nfc library (nfc.cpp + nfc.h) that Elechouse provides.
    So I am going to use that one instead.

  • I'm using it with arduino uno...its showing "board pn53x not found"...what can i do?

  • Community Helper

    Make sure your PN532 board is connected to the arduino correctly, and its power light is on.
    What method are you using for the connection?

  • yeah..the power light is on...i connected vcc --> 5v ; gnd --> gnd ; sda --> A4 ; scl --> A5

  • Community Helper

    That does seem like it should be right, sometimes if sda and scl are swapped you'll get nothing.
    Is your sketch set up for using IIC correctly?

  • @Lokki Yeah..i'm using the example of the library provided by elechouse

  • Still can u send me any of your code..!?

  • Community Helper

    Search the forums, I've left bits and pieces of horrendous code around here before.
    It would actually be better if you show us your code. From a troubleshooting point of view, like.

  • #if 0
    #include <SPI.h>
    #include <PN532_SPI.h>
    #include <PN532.h>
    #include <NfcAdapter.h>
    PN532_SPI pn532spi(SPI, 10);
    NfcAdapter nfc = NfcAdapter(pn532spi);
    #include <Wire.h>
    #include <PN532_I2C.h>
    #include <PN532.h>
    #include <NfcAdapter.h>
    PN532_I2C pn532_i2c(Wire);
    NfcAdapter nfc = NfcAdapter(pn532_i2c);
    void setup(void) {
        Serial.println("NDEF Reader");
    void loop(void) {
        Serial.println("\nScan a NFC tag\n");
        if (nfc.tagPresent())
            NfcTag tag = nfc.read();

  • Community Helper

    Okay, for comparison I'm going to copypasta my crappy car starter sketch:

    int triggerPin1 = 2;
    int triggerPin2 = 3;
    int triggerPin3 = 4;
    int indicatorPin1 = 5;
    int indicatorPin2 = 6;
    int indicatorPin3 = 7;
    int indicatorPin4 = 8;
    int handbrakePin1 = 9;
    int carRunState = 0;
    int handbrakeState = 0;
      #include <Wire.h>
      #include <PN532_I2C.h>
      #include <PN532.h>
      PN532_I2C pn532i2c(Wire);
      PN532 nfc(pn532i2c);
    void setup(void) {
      pinMode(triggerPin1, OUTPUT);
      pinMode(triggerPin2, OUTPUT);
      pinMode(triggerPin3, OUTPUT);
      pinMode(indicatorPin1, OUTPUT);
      pinMode(indicatorPin2, OUTPUT);
      pinMode(indicatorPin3, OUTPUT);
      pinMode(indicatorPin4, OUTPUT);
      pinMode(handbrakePin1, INPUT);
      Serial.println("Hello! I'm a Car!");
      uint32_t versiondata = nfc.getFirmwareVersion();
      if (! versiondata) {
        Serial.print("PN53x key scanner board not online");
        while (1); // halt
      // Got ok data, report state
      Serial.print("Reader Online, ");
      // Set the max number of retry attempts to read from a card
      // This prevents us from waiting forever for a card, which is
      // the default behaviour of the PN532.
      // configure board to read NFC tags
      Serial.println("Waiting for a valid key");
    void loop(void) {
      String ringUid;
      boolean success;
      uint8_t uid[] = { 0, 0, 0, 0, 0, 0, 0 };  // Buffer to store the returned UID
      uint8_t uidLength;                        // Length of the UID (4 or 7 bytes depending on ISO14443A card type)
      // Wait for an ISO14443A type cards (NFC Ring, Mifare, etc.).  When one is found
      // 'uid' will be populated with the UID, and uidLength will indicate
      // if the uid is 4 bytes (Mifare Classic) or 7 bytes (NFC Ring or Mifare Ultralight)
      success = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, &uid[0], &uidLength);
      if (success) {
        // Display some basic information about the card
    //    Serial.print("  UID Length: "); Serial.print(uidLength, DEC); Serial.println(" bytes");
        Serial.print("  UID Value: ");
        for (uint8_t i = 0; i < uidLength; i++)
          Serial.print(uid[i], HEX);
          ringUid += String(uid[i], HEX);
        Serial.println(ringUid + "\n");
        if (ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx"){
          Serial.println("Key accepted!");
        if ((ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx") && (carRunState == 0)){
          Serial.println("PERMISSION GRANTED, SYSTEMS ON");
          digitalWrite(triggerPin3, HIGH);   // sets latching relay trigger on for ignition mode in car to allow start
          digitalWrite(indicatorPin2, HIGH); //show state, second LED
          delay(200);                  // waits briefly
          digitalWrite(triggerPin3, LOW);    // removes latching relay trigger
          carRunState = carRunState++;
        else if ((ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx") && (carRunState == 1)){
          handbrakeState = digitalRead(handbrakePin1); //check if handbrake is on or off
          if (handbrakeState = 0){//if handbrake is on then safe to crank car, if not then skip this mode entirely
            Serial.println("ENGINE CRANKING");
            digitalWrite(triggerPin1, HIGH);   // triggers output for engine starting
            digitalWrite(indicatorPin3, HIGH); //show state, third LED
            delay(2000);                  // waits for a second
            digitalWrite(triggerPin1, LOW);    // removes triggered output 
            Serial.println("ENGINE CRANKING COMPLETE");
          carRunState = carRunState++;     
        else if ((ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx" || ringUid == "xxxxxxxxxxxxxx") && (carRunState > 1)){
          Serial.println("SYSTEM OFF, SLEEP TIME");
          digitalWrite(triggerPin2, HIGH);   // Trigger latching relay to reset for vehicle OFF
          digitalWrite(indicatorPin1, HIGH); //show state, LED1 on
          digitalWrite(indicatorPin2, LOW); //LED2 off
          digitalWrite(indicatorPin3, LOW); //LED3 off
          delay(200);                  // waits briefly      
        digitalWrite(triggerPin2, LOW);    // Removes latching relay reset trigger
        carRunState = 0;
        digitalWrite(indicatorPin1, LOW); //LED1 off

  • Community Helper

    You see at the start where I just chopped out the mess and left it with the I2C stuff? Maybe try doing something like that and see what happens.

  • That's also not working...same error..!!

  • Community Helper

    Ok, so the code definitely works, and definitely works on an UNO with a PN532 V3 set to I2C mode.
    So, logically the only things that could be different in your case are the I2C wiring and the I2C mode setting on the board you have.
    Double check that your board is set to function in I2C mode, then double check your wires, maybe try swapping the two data wires around to see if that helps.

  • No change..still no success....same error

  • Community Helper

    Do you think you could take a picture of your setup?

  • Community Helper

    Ah, there's your problem - it's not set to I2C mode.

    See the little bank of two physical switches right near the I2C connection points? switch 1 needs to be in the UP position for on.