The larger 3 watt RGB LEDs are very bright and colorful, but if you don't get the power just right - POOF! Now your RGB is R(nothin')B. The Star Controller tames this LED so you can power it up with 5 to 12V and use any regular 5V signal to control each channel.
RGB LEDs are fun. LARGE RGB LEDs are even more fun, but with their funky current requirements, you usually have to pick and tune transistors to make it suitable for your project. And if you get it wrong, your RGB turns into an R(nuthin')B.
We even found a convenient diffuser container to make it appear HUGE.
Simply put, this kit is a great way to simply add a powerful, colorful LED to your project. Check the resource page for Arduino and SB-FireFly sample code.
As the constant-current regulators are a linear device, they generate a noticeable amount of heat, especially at the higher input voltage levels (see the graph in the documentation). To counter this, use a 10W switching voltage regulator on the Vin line to the Star Controller to bring the high voltage efficiently down to 5~6V, where it will operate much cooler.
Oh, did we mention it's a OSHW-compliant kit? Source documentation is available under the Documentation Tab.