A little sketch to check the functionality of a WS2812 LED strip with an Arduino.
It shows some color patterns to check the functionality of the LEDs,
and a ruler like pattern for easily counting the total number of LEDs of the strip.
Change the displayed pattern with a pushbutton connected to pin 2 (and GND).
Connect the LED strip to pin 6; max. 300 LEDs are addressed by default.
Uses FastLED library for controlling the WS2812 LEDs.