• Registered: 2011-12-02
  • Posts: 2

Topic: Simple ACR122U <-> Nexus (S) communication

Hi,
in a project I have 3 ACR122U readers connected to a simple PC running Fedora Core. I am able to use the readers to read the UID from passive NFC tags for which I now the UID in the back-end, which is enough. However, I also need to be able to uniquely identify a NFC-native Android Phone as well, like Nexus S and Nexus. I need nothing advanced, just being able to transfer an unique, but not random, code between the devices.

As I understand I can't set the Nexus in tag emulation mode, which would have been very convenient, I need to take a different approach. The alternatives I'm looking at are:

1. Sending a simple NDEF with a key I also know on the receiving side. This I read with the ACR122U
2. Set the currently active ARC122U to emulate a tag with an ID I can push to the Nexus through the back-end, and the the Android app can verify that the ID is correct.

So which approach I am most likely to get working? At the moment I have stability problems as my experiments with the different libnfc example programs leads to one or several of the ACR122U readers being locked (nfc-list works, which is enough for getting the UID's from the passive tags I have for the project).

Thanks in advance,
Per, Sweden

  • Registered: 2011-12-02
  • Posts: 2

Re: Simple ACR122U <-> Nexus (S) communication

Answering my own post: the setup I'm using now is to emulate a tag with the ACR122U which I can correctly read with an Galaxy Nexus (the new version).

/Per

  • Registered: 2012-01-03
  • Posts: 3

Re: Simple ACR122U <-> Nexus (S) communication

Hi Cagecurrent:

  • Registered: 2012-01-03
  • Posts: 3

Re: Simple ACR122U <-> Nexus (S) communication

I also want to use Nexus android phone to transfer some data through NFC with my PC's application. So i choose ACR122U as the additional
device to help PC with NFC ability. My question is can ACR122U work under NFC p2p mode? If not, how to use ACR122U to emualte a tag? Because i thought this device only acts as a tag reader/writer.

Many Thanks
Nathan

  • rconty
  • Administrator
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  • Registered: 2009-04-22
  • Posts: 673

Re: Simple ACR122U <-> Nexus (S) communication

nathan wrote:

IMy question is can ACR122U work under NFC p2p mode?

The ACR122U libnfc's driver does not support timeouted operations due to PC/SC.
So, yes it can work in P2P mode but will not be bullet-proof and not recommended in production.

nathan wrote:

If not, how to use ACR122U to emualte a tag?

Same problem with emulation... You will not be able to stop/cancel emulation while started.

nathan wrote:

Because i thought this device only acts as a tag reader/writer.

ACR122U seems to be designed to work behind PC/SC only and PC/SC does not provide more than tag reading/wrinting natively.

Romuald Conty
  • Registered: 2012-01-03
  • Posts: 3

Re: Simple ACR122U <-> Nexus (S) communication

Hi Romuald:

    Many thanks for your reply! From your reply, ACR122U seems to be designed as NFC terminal for tag reading/writing. In the meantime, i found the information from Internet that it's a bit difficult to turn Nexus Phone with Android 2.3.3 into card emulation mode. So would you recommend some devices which can help my scenario? I want to use Nexus Android 2.3.3 phone to communicate some data with desktop using NFC.

Thanks
Nathan