http://blog.emfcamp.org/post/28558155390/revealing-tilda-our-camp-badge#notes
The design is fully open-source and based on the Arduino compatible Vinciduino, as we wanted to give people a device that they could actually use for something useful after the camp has ended, rather than sitting in a drawer.
TiLDA is powered by an ATMega 32U4 and comes equipped with 2.4 ghz wireless communications, infrared communications, two RGB LED’s, and a powerful lithium polymer battery that is rechargeable via microUSB. It also has a button, just in case. There are plenty of free I/O pins for you to augment your TiLDA, and it can be programmed using the standard Arduino software. We can’t wait to see what you do with it at EMF.