This is the FadeCandy from Adafruit, a USB controlled LED driver with on-board dithering to help illuminate your Neopixel project. Even though the FadeCandy was designed to be used alongside of the NeoPixel Line the driver also works with most WS2811/12 LEDs. This little board has been designed to help both beginners and the advanced LED techie!
Eight outputs line the bottom of the FadeCandy to provide you with a way to support up to 512 LEDs total assigned to each output in eight strips of 64 LEDs each. Thanks to the firmware each driver utilizes a unique built in dithering algorithm to help in color correction to make the light from each WS2812 apear and move and fade smoothly.