NFC tag with usb interface?

[bela.the.king]

Hello,

I am quite unexperienced with the NFC technology, so I kindly ask for your help. We are working on a smart poster project, and we currently trying to add an NFC module to it, where URLs were stored and could be accessed by mobile phones. We can not use a simple passive NFC tag, because the content should change dynamically with the ad on the poster.

I have read many flyers and tech documents about NFC hardwares, however, I am still not sure which one to use. What we need, is an NDEF compatible device with storage capabilities and a usb/rs232 interface to receive instructions from our host system.
Could you provide me with any information which may help to choose the correct technology to our project?

Furthermore: I have an idea for an easy solution. A simple usb NFC reader/writer + a passive NFC card attached to it. The host system could modify the content of the card using the writer, and the mobile phone could read the updated url from the card. Could this system work well in practice? Isn't that possible, that the concurrent reading/writing causes some kind of interference in the communication?

Thanks
A.Berke

[Terenas]

The reading/writing could be a problem.

Maybe your heard that the NFC has a P2P mode ? If not check more

Youre solution could be good except the fact of concurrent reading/writing. But with P2P mode and the beginning of your solution we can imagine this :
a simple NFC reader which send the dynamic content.

But I have great practice with the P2P mode. Maybe someone could tell you more..

[bela.the.king]

I have heard about peer-to-peer, but I was not sure, that this mode could be used for downloading NDEF formatted data. I thought it is only for exchanging data between phones such as address book or bluetooth communication params.
Should I use a p2p capable device in my project?

[Terenas]

As I said I'm not very "pro" with p2p mod. But the "quick" way to change the content dynamically could be this way.

Your solution could be good. I only see one improvement : disconnecting the card reader when the content has been changed. In this situation you will no more have concurrent accesses. You'll just have to start up the reader, read/write the new content and shutown the reader.

[RicardoPortela]

To use the NFC-IP1 connection, you must write a midlet, and use it to exchange data between the device in the poster and the mobile phone. That's a disadvantage when comparing to simple NDEF data written on a tag. But is by far a more capable solution, enabling very interesting scenarios.

I'm currently working on a project that enables this and others scenarios.
You can check an excerpt from a presentation I gave on the subject here.
The document has a comments layer with some context information.

Best regards
Ricardo Portela

[GLNeedham]

Hi,

Personally I would recommend using an NDEF record on an emulated tag that way it will work with native software on the phone - you will not need to write and install an applet.

There are a few NFC reader chips which will allow you to do card emulation - timing can be an issue but if you have a dedicated local micro then it is possible.

The idea of a tag and a reader can work, you just need to make sure you update the tag contents when no one is trying to read it.

For a complete reader with emulation possibilites try ACR122 at www.acs.com.hk

[lanmi]

Hi,

For a complete reader with emulation possibilites try ACR122 at www.acs.com.hk

I'm also in need of a reader which can emulate the NFC tag or smart card. So, I would like to know if this reader really can do that, because I found noting in ACR122 spec about smart card emulation mode. Does anybody have experience in that issue?

[praghuna]

As far as i know, acr122 is only a reader and can't do any tag emulation.

You can reader many different types of card using acr122 besides connecting

in an NFCIP-I compatible mode with another device having similar capabilities.

But why do you want the reader to emulate a tag ?

[lanmi]

I'm working for a mobile operator. We explore how NFC can be useful for us. At this point we're trying to do an example NFC implementation on existent mobile pay systems, and they are primarily based on phone to service communication thus card reader can be used as information source(e.g. providing bill code) and all payment will be handled the same way it was without NFC. I know that payment in NFC is supposed to be carried out in a different way, but what we are looking now is a proof of a concept thing and then we can continue our research more thoroughly.

Ok, I think that for that mater p2p mode can be useful too, but it would be nice to find a card reader that can do the card/tag emulation (I know there must be some, otherwise "smartcard emulation mode" term wouldn't exist)so we can have more room for maneuver.

So, do you (or anybody) know about any good reader that can do the card/tag emulation (p2p mode is mandatory of course)?

Thanks