BulletPixels are powerful LEDs that can produce light of varying intensity and color.
Most LEDs are too simple: just one color, and one setting - on or off. If you’re looking for a bit more flexibility, the BulletPixel 8mm LEDs from Samurai Circuits are just the ticket. These powerhouses somehow cram an integrated circuit and three diodes (RGB) into a single LED enclosure, allowing you to program variable intensity and color for each LED. The possibilities are pretty darn cool: fade intensity or change color as battery life declines, indicate when an iron is hot for soldering as BulletPixels creator Tully Gehan does... You can also daisychain these LEDs together, and each remains individually addressable through serial communication.
Samurai Circuits provides extensive documentation, including this Arduino library and this data sheet for the WS2811 chipset that powers BulletPixels.
InMojo supports the Open Source Hardware Definition v1.0