This is an open source NFC stack for the arduino microcontroller that allow peer-to-peer communication between an embedded platform and an Android NFC enabled device. The library implements the Ndef Push Protocol (NPP) and has been tested with an Android NFC-enabled phone running Android 2.3.3.
Android supports two peer-to-peer NFC protocols: NDEF Push Protocol (NPP) and Simple NDEF Exchange Protocol (SNEP). NPP was introduced in Android 2.3.3. SNEP was introduced in Android 4.0. Android 4.0 phones try SNEP first and then use NPP. This repository implements NPP. Theoretically it should work with Android 4.0 phones that support SNEP. However, I have not heard of a success case. A fork of this project NFC_Shield_DEV implements the newer SNEP protocol. I recommend phones that use Android 4.0 or newer use the fork (SNEP protocol). Furthermore, it has bug fixes that have not been backported to this repository.
NDEFPushProtocol - Implements the NDEF push protocol as described by http://static.googleusercontent.com/external_content/untrusted_dlcp/source.android.com/en/us/compatibility/ndef-push-protocol.pdf
NFCLinkLayer - Implements the NFC LinkLayer Protocol that is used by the NDEFPushProtocol. The Link Layer protocol can be found at http://www.nfc-forum.org/specs/spec_list/.
PN532 - Handle communication between the embedded device and the PN532 NFC reader.
The example is arduino program that send and recieves NDEF messages that contain text. When it recieves an NDEF message, it retrieves the text payload from the NDEF message and updates the NDEF message it sends to contain the recieved text payload. The program works with the example Android NFC program, stick notes (The code for stick notes can be found at http://nfc.android.com/).