Rainbow Strip

The idea of this project is to create a wearable, water resistant, animated rainbow light strip to be shamelessly be exploited for money during pride festivities. Based on an Adafruit Neopixel strip, an Arduino nano and any standard 5v mobile power bank, this silly device can keep the proud individual dancing for hours on end.

The core of this project is the Arduino sketch that creates a rainbow corresponding to the number of LEDs in your WS2011b (or similar) light strip. The main feature is the algorithm that uses trigonometry to create a colour wheel where the circumference is equal to the number of LEDs in the strip. It isn't 100 percent exact, simply because the relationship between PWM level and brightness of an LED is not anywhere near linear. That said, you don't get the smoothest blend between the colours, but the major colours show through clearly. In brief, the formula for creating the colour wheel is essentially:

x = 2 * Pi / (LED# +1) (where LED# is address of t