Rainbow Fun

• Add the following new function to the end of your sketch. Don’t worry, you don’t have to understand it just now! It’s borrowed from the example sketch you ran earlier.

uint32_t Wheel(byte WheelPos) {
    WheelPos = 255 - WheelPos;
    if(WheelPos < 85) {
        return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
    }
    if(WheelPos < 170) {
        WheelPos -= 85;
        return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
    }
    WheelPos -= 170;
    return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
}

This function lets you choose any numer from 0 to 255, and it mixes a colour for you.

• Now add another new function. See if you can spot the for loop in it!

void lightAllRainbow() {
    for(uint16_t i=0; i<strip.numPixels(); i++) {
        strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels())) & 255));
        strip.show();
    }
}

There’s a bit of math in here! It’s there to pick a nice selection of colours evenly from across the whole rainbow.

• All that’s left is to call the function. Change the loop function so that it has just this line of code in it. Then verify and upload your sketch to see a lovely rainbow of colours.

void loop() {
    lightAllRainbow();
}

You don’t need to pass any parameters this time, because the new function figures out the colours for you!

• How about adding a delay? Let’s write a new function that’s similar to the one above, but with a delay added to the loop so it animates your NeoPixels:

void animateRainbow(uint8_t wait) {
    for(uint16_t i=0; i<strip.numPixels(); i++) {
        strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels())) & 255));
        strip.show();
        delay(wait);
    }
}

• Change the function call in the loop function and add a second line of code to call your other animate function too:

void loop() {
    animateRainbow(100);
    animateOneColour(strip.Color(0, 0, 0), 100);
}

Try it out on the Flora!

Challenge: Try making your own sequences

• Have a go at combining various different calls to the animateRainbow function and your other functions. Your imagination is the limit!

• You can do loads of cool things using the tricks you’ve learned with colours, for loops, and delays. If you want to see some more examples, check out the strandtest sketch that you used to test out the NeoPixels.