The UltiController allows you to work with your Ultimaker in an entirely new way!
You can directly observe the effects of increasing the speed up to the optimal point where your print finishes nice and fat, and still comes out with good quality.
With the UltiControllers your 3D printer will be able to stand alone, so no need for having a computer attached! This is great, it allows you to put the machine aside and use your computer for something else. You’re not forced to sit next to the Ultimaker, as addictive as it may be to watch it all the time. Also, it helps minimize the impact of a laptop battery going down, the occasional need for a reboot, etc.
The UltiController kit can be added to the existing electronics as of version 1.5. All of the units sold since March 2011 are backwards compatible. Also, the 1.5.6 version of the UltiController (shipping since February 2012) is automatically self-powered. For all Ultimaker electronics before the version 1.5.6, a small patch is required (a single wire) which will make the Ultimaker self-powering (otherwise you still need to power it over USB, requiring another USB-charger/outlet).
The UltiController will print your G-code files from a SD card.
The UltiController is developed by Bernhard Kubicek. The story of how it came to be, can be found here.