rainbow.lua

function rainbowize()
    green = {0, 61, 127, 193, 255, 255, 255, 255, 255, 255, 255, 255, 255, 193, 127, 61, 0, 0, 0, 0, 0, 0, 0, 0, 0}
    red   = {255, 255, 255, 255, 255, 183, 127, 61, 0, 0, 0, 0, 0, 0, 0, 0, 0, 61, 127, 193, 255, 255, 255, 255, 255}
    blue = {0, 0, 0, 0, 0, 0, 0, 0, 0, 61, 127, 193, 255, 255, 255, 255, 255, 255, 255, 255, 255, 193, 127, 61, 0}

    rainbow_i = (rainbow_i % table.getn(green))+1

    return red[rainbow_i], green[rainbow_i], blue[rainbow_i]
end

function dupa()
    ws2812.init()
    rainbow_i = 0
    local dir, i, buffer = 0, 0, ws2812.newBuffer(300, 3);
    buffer:fill(0, 0, 0);
    tmr.create():alarm(25, 1, function()
        if (dir==0) then
          i = i + 1
          if (i == buffer:size()) then
            dir=1
          end
        else
          i = i - 1
          if (i == 0) then
            dir=0
          end
        end
        buffer:mix(220, buffer)

        r,g,b = rainbowize()
        buffer:set(i % buffer:size() + 1, r, g, b)
        buffer:set((2 * i) % buffer:size() + 1, r, g, b)

        ws2812.write(buffer)
    end)
end

dupa()