in neopixel.ts [495:506]
export function create(pin: DigitalPin, numleds: number, mode: NeoPixelMode): Strip {
let strip = new Strip();
let stride = mode === NeoPixelMode.RGBW ? 4 : 3;
strip.buf = pins.createBuffer(numleds * stride);
strip.start = 0;
strip._length = numleds;
strip._mode = mode || NeoPixelMode.RGB;
strip._matrixWidth = 0;
strip.setBrightness(128)
strip.setPin(pin)
return strip;
}