please i want extention to read serial number of nfc tag
Hi Gan_Azaz,
actually I worked only with Mifare Classic.
If I can in next future I think to add support for Mifare Ultralight and then, if I am able, NtagA
It depends about time and other works
Best Regards
Marco
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Have you tried App Inventor's NFC blocks?
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yes .. i did .. but nfc blocks in mit app just support write and read text
What is special about your serial numbers? Can you up load an image or two?
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Gan Azaz is speaking about the uid (unique identifier) that is inside every tag.
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yes .. as Marco said
I see. Yet once a tag is locked, is the UID available? What would be the purpose, and why not have a UID as the data?
Uid is a code written by the manufacturer in a special area of the tag (read only) it is always available (on my experience). The Uid length changes according to the technology used Mifare Classic 4 bytes Ultralight 7 bytes and so on
So it's safer than writing your own uid in a data area of the tag.
Some access control systems use uids to allow access or not
To the best of my knowledge, Mifare Classic 1K cards use block 0 of sector 0 to hold the card UID. The UID is either 7 bytes long (for newer cards) or 4 bytes long (for older cards). Ultralights use the same block and use a 7 bit UID,
A block holds 16 bytes of data and the remaining bytes of block 0 sector 0 are reserved for manufacturer specific information. There is no difference between reading this block and any other block of the card. However, most manufacturers make this block read-only and you can't overwrite the UID like you can overwrite data in any other block. The default encryption key of 0xFFFFFFFFFFFF s used to authenticate this block for reading.
Note that some Chinese manufacturers sell cards where block 0 sector 0 is overwritable, so it is possible for people to use such a card to emulate other cards. Therefore, UIDs are not secure, and are not guaranteed to be unique. They are intended only for use in the anti-collision step of reading/writing a card. The terminal uses the UID to select the card that it wants to communicate with (in the event that multiple cards are activated in the near field of the terminal). Writing your own UID data to some other block in any other sector and changing the encryption keys and access controls for that sector are the only way to ensure the authenticity of a card that you issue to users.
I haven't used the AI2 NFC component, but if you can read and write blocks on a Mifare Classic 1 K card, then you can read the manufacturer card UID in the same manner. I have implemented an Arduino (Particle) card reader/writer with a PN532 based RFID board. We have supplied lots of information about RFID cards as part of this open source project. For details, see:
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My update