I am experimenting with NFC Tags and automation on Home Assistant. I have bought a few writeable NFC tags for these experiments. They are cheap, but I wouldn’t say I like wasting them while testing.
Since Flipper Zero can simulate NFC tags, I decided to use it for my tests.
If you want to do the same, here is what you need to do.
Flipper Zero stores NFC Tag data in a plain text file with a .nfc extension. There is a simple command line python script that allows you to write an NFC tag in the Flipper Zero format. Thank you to evilpete for making this available.
#!/usr/bin/env python """ Generates NFC with URL address data and outputs Flipper NFC "save" file this is a 5 min hack, No Guarantees ./nfc_gen_url.py https://youtu.be/dQw4w9WgXcQ "Rick Roll" > rickroll.nfc requires ndeflib Written By: Peter Shipley github.com/evilpete From pkg https://github.com/evilpete/flipper_toolbox """ import sys try: import ndef except ImportError as e: print("Failed to import ndef") print("https://github.com/nfcpy/ndeflib") sys.exit(0) # make sure output is utf-8 sys.stdout.reconfigure(encoding='utf-8') # for debuging verbose = 0 nfc_header = """Filetype: Flipper NFC device Version: 2 # generated with flipper_toolbox Device type: NTAG215 # UID, ATQA and SAK are common for all formats UID: 04 10 56 01 74 48 03 ATQA: 44 00 SAK: 00 # Mifare Ultralight specific data Signature: A5 80 A4 CC A0 C3 A1 F6 8B BE 6F EE 83 A6 B9 EE 36 F8 FB C8 14 5A 23 AA 29 DB 78 56 07 B9 6B 92 Mifare version: 00 04 04 02 01 00 11 03 Counter 0: 0 Tearing 0: 00 Counter 1: 0 Tearing 1: 00 Counter 2: 0 Tearing 2: 00 Pages total: 135 """ data_static = [ 0x04, 0x10, 0x56, 0xCA, # 01 serial number 0x01, 0x74, 0x48, 0x03, # 02 serial number 0x3E, 0x48, 0x00, 0x00, # 03 serial number, internal, lock bytes, lock bytes 0xE1, 0x10, 0x3E, 0x00, # 04 Capability Container ] conf_pages = [ 0x00, 0x00, 0x00, 0xBD, # 130 0x04, 0x00, 0x00, 0xFF, # 131 0x00, 0x05, 0x00, 0x00, # 132 0x00, 0x00, 0x00, 0x00, # 133 0x00, 0x00, 0x00, 0x00, # 134 ] def print_nfc_sub(t_data, file=sys.stdout): print(nfc_header, end='', file=file) p = 0 for x in range(0, 540, 4): print(f"Page {p}: {t_data[x]:02X} {t_data[x + 1]:02X} " f"{t_data[x + 2]:02X} {t_data[x + 3]:02X}", file=file) p = p + 1 def gen_nfc_sub(tag_data): tag_message = [] data_list = [] for x in tag_data: if x[0] == 'txt': tag_message.append(ndef.TextRecord(x[1], "en")) elif x[0] == 'url': tag_message.append(ndef.UriRecord(x[1])) if verbose: print(x, file=sys.stderr) print(tag_message[-1:], file=sys.stderr) buf = b"".join((ndef.message_encoder(tag_message))) m_len = len(buf) if verbose: print("buf", m_len, hex(m_len), buf, file=sys.stderr) data_list.extend(data_static) data_list.append(3) # Message Flags if m_len < 255: data_list.append(m_len) # Type Length else: data_list.append(0xFF) lenStr = hex(m_len)[2:].rjust(4, "0") data_list.append(int(lenStr[0:2], 16)) data_list.append(int(lenStr[2:4], 16)) data_list.extend(list(buf)) data_list.append(0xFE) # end of Data data_len = len(data_list) if verbose: print("data_list", data_len, data_list, file=sys.stderr) x = 520 - data_len data_list.extend([0] * x) data_list.extend(conf_pages) return data_list # url_str = "https://youtu.be/dQw4w9WgXcQ" # title_str = "Rick Roll" if __name__ == '__main__': arg_data = [] for a in sys.argv[1:]: if a.startswith("http"): arg_data.append(("url", a)) else: arg_data.append(("txt", a)) if not arg_data: print("requires at least one URL argument\n" "Please provide URL and optional Title\n\n" f"{sys.argv[0]} : https://some.url 'Title'") sys.exit() nfc_data = gen_nfc_sub(arg_data) print_nfc_sub(nfc_data) sys.exit() Copy the script on your computer (e.g. nfcdata.py) and run it:
python3 nfcdata.py "Test data"
This will create a file that you can upload to your Flipper Zero using the qFlipper desktop application.
You will now be able to emulate the tag on the Flipper Zero.