The initial modifications to the Adalight code to incorporate the
FastLED library and work with WS2812B LEDs were done by James Bruce
(@jamesabruce). I can't find a way to do a pull request on a Gist, so
I'm copying his code in full here.
Original Gist: https://gist.github.com/jamesabruce/09d79a56d270ed37870c
Upon initial power-up or reset, and each time the serial port is opened,
the LEDs will briefly flash through red, green and blue, then off. This
can be used to diagnose whether the wiring between Arduino and LEDs is
correct, and to spot any breaks in the strand. Unrelated, Adalight (the
Processing code) now issues an all-off state to the LEDs on most (but
not all) exit cases.