This is a strip of 5 self adhesive RFID/NFC 13.56 MHz NTAG 213 Stickers, each “item” you buy is a strip with 5 stickers, peel em off and stick them to things you want to use with RFID. Sticker diameter is about 25mm.

I have two types

• Plain – suitable for sticking to plastic etc
• Ferrite backed – suitable for sticking to metal

the reason for the difference is to do with transmit/receive, not stickiness. If you put a plain one on a metal plane you will have problems communicating.

The NTAG213 sticker has as you would expect a unique ID for each sticker for simple cases, and also can store 144 bytes of user data if you so wish.

These stickers can be read from and written to using the MFRC522 RFID Reader and a microcontroller like an Arduino. The MFRFC522 Arduino Library can be used to do this. The maximum read/write distance is about 1-2cm.

Note that the MFRC522 Library will “detect” these as Mifare Ultralight/Ultralight-C because it doesn’t know any different, and it’s dumpinfo will not show the complete memory contents because it only shows the first 16 pages which is all an Ultralight has. You can change in the library MFRC522.cpp around line 1648 in function PICC_DumpMifareUltralightToSerial the maximum page count to 43 to enable dumpinfo to show the full data.

Note the memory layout in the image capture from the NTAG213 datasheet ( https://tinyurl.com/2a34ldfy ).

The intricacies of reading and writing to/from RFID cards is left to the reader to explore, but here’s a link to Arduino code you can use to test writing and reading to these stickers ( http://tinyurl.com/y6t3wt5h ), that should get you started.

Can you read these with phones that have NFC, I expect so but I don’t use phones generally, so up to you to experiment ( http://tinyurl.com/y4awb94j ).

See all my listings: https://tinyurl.com/26tzbx6d