You might consider the use of the following devices donated to FIRST Choice (I know yours is not a FIRST project but you can pick these up really inexpensively at DigiKey or Mouser). We'll be providing a pre-built binary for general use and releasing the source code for it so that some teams (or folks like yourself) may modify it for their specific purposes.
http://www.firstchoicebyandymark.com/en/fc14-011
David Yanoshak (dyanoshak) will be posting additional details of this and some interfacing options in the near future (a couple of days from now).