This firmware will turn your FutureStack badge into a simple NFC tag reader. To get started, register an account with http://electricimp.com, BlinkUp your badge using the Electric Imp Android or iOS mobile app, and create a new model using the IDE containing the code in device.nut (no need for agent code). Hit "Build and Run" and your badge should be ready to go.
To explore more about Electric Imp, check out their dev center here. If you want to use your Imp in your own hardware project, check out this page to find a breakout board.
The NFC chip on the badges is an NXP PN532. You can find the datasheet here. The user manual (a bit higher level) is here and an application note is here. With these datasheets, you'll be able to tailor the NFC chip's behavior to your heart's content.
Any CR123 3v battery should be suffient as a replacement for the one provided.
Portions of this code used with permission from Javier Montaner.
Copyright (c) 2013 New Relic, Inc. See the LICENSE file for license rights and limitations (MIT).