• TR44
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  • Registered: 2010-04-01
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Topic: Tag emulation with ACR122

Hi,

I'm currently working on a project which consists in sending informations (URL or short text message) to a mobile (Nokia 6212) from an ACR122 reader/writer.
I think the best way would be emulating a tag with the ACR122. I tried the nfc-emulate example but unfortunately, it doesn't seem to work. The initialization seems to succeed but the reader doesn't receive any reply.

Here is the log I got, after what the program keeps waiting for a response from the mobile :
http://img339.imageshack.us/img339/4774/logm.png

Did anyone succeed in emulating a whole mifare1k tag with an ACR122 ?
Would it be possible to receive and display the informations on the mobile ?

  • TR44
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Re: Tag emulation with ACR122

Any ideas ?

  • rconty
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Re: Tag emulation with ACR122

Hello,

nfc-emulate is a "proof-of-concept" of emulation using NFC device. ATM, it doesn't handle whole MIFARE Classic emulation.
I think there is a bit of work before being able to emulate a working Mifare Classic.
BTW, I actually don't use emulation, so I'm not at the best place to talk about.

Romuald Conty
  • roel
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Re: Tag emulation with ACR122

Dear TR44,

Thank you for your question.

The short answer to this is: use a different reader (not a Nokia phone) to test.

The long answer is: Because the ACR122 usb-hardware (and corresponding host-pc usb-software stack) is not fast enough, it will not respond with the ATQA in time. More about the anti-collision can be found in this example. This is not really solvable by keep using the (slow) usb-interface. The PN533 dongles for example, have direct USB support, they are twice as fast as the ACR122 readers in USB communication. But this is still around 5 times to slow to be in time for a Nokia phone (or e.g. public transport gate) to respond in time.

If you use two ACR122 readers, you can use the nfc-anticol example and the nfc-emulate together. They will show that with enough patient, the proof-of-concept works. To make this work for fast readers you should use a hardware specific device like the mikeycard for example. This will use a dedicated uC communicates fast over the SPI, I2C or USART connection to the PN53x chip itself.

I hope this answers the question for you?

Best regards,

  Roel

  • TR44
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Re: Tag emulation with ACR122

Hi,

Thank you for your answers.

I better understand why this solution isn't workable for the moment.

Actually I have to manage with the devices I have... I'm going to do some tests using a dongle but I think a better way to  transfer data to the mobile is to develop a midlet receiving data from the reader/writer.

Tag emulation would have been the most appropriate solution but I'm going to try otherwise.

Thanks again !

Best regards,

Tony