/arduino-nfc

A simple Arduino-based NFC tag reader and writer using the PN532 module. Supports Mifare Classic tags, allowing you to clean, format, and write NDEF records (URLs, text, etc.). Works with iPhone and Android NFC readers.

Primary LanguageC++

NFC Tag Reader & Writer using PN532

This project allows you to read, clean, format, and write data to Mifare Classic NFC tags using the PN532 module.
It works with Arduino-compatible devices and uses I2C for communication.

Features

  • Read NFC tags (Mifare Classic) and display their contents
  • Clean and format NFC tags for NDEF compatibility
  • Write a URL (or other NDEF messages) to an NFC tag
  • Works with iPhone & Android NFC readers

Requirements

  • Arduino board (Uno, Mega, etc.)
  • PN532 NFC Module
  • Mifare Classic NFC Tag
  • PlatformIO / Arduino IDE

Installation

  1. Clone this repository: 
    git clone https://github.com/FilipRokita/arduino-nfc
  2. Open the project in PlatformIO or Arduino IDE.
  3. Connect your PN532 module via I2C:
    • VCC → 5V
    • GND → GND
    • SDA → A4
    • SCL → A5

Usage

1️⃣ Writing to NFC Tag

  • Set writeMode = true; in the code.
  • Upload the sketch to your Arduino.
  • Open Serial Monitor (115200 baud).
  • Place an NFC tag near the reader.
  • It will:
    • Clean the tag.
    • Format it.
    • Write a predefined URL to the tag.

2️⃣ Reading an NFC Tag

  • Set writeMode = false;
  • Upload and open Serial Monitor.
  • Place a tag near the reader.
  • The program will display the tag’s UID, type, and stored NDEF records.

Troubleshooting

  • If formatting fails, the tag may be locked or require a specific authentication key.
  • If reading fails, check wiring and make sure the tag is supported (Mifare Classic).
  • If not working on iPhone, ensure the tag is formatted for NDEF and contains a valid NDEF record.