The code presented on this page can be downloaded or found in the Arduino examples menu under Examples → SpinWearables → Dancing_with_Color → Rainbow_Chase_Advanced.

A Few LEDs with continuously changing colors “chasing” each other

This is a sketch based on the Rainbow_Chase example from animations and patterns. In the Animations and Patterns Activity a “delay” or “offset” between the numbers governing the colors of a given LED was introduced to make them look as if they are chasing each other. Our comments in this sketch focus on the differences from that Animations and Patterns Adventure. In particular, we focus on how we now use rotation rather than time to update the animation.


#include "SpinWearables.h"
using namespace SpinWearables;

void setup() {
  SpinWheel.begin();
}

int r_cum = 0;

void loop() {
  SpinWheel.readIMU();

Here we measure the rotation around the x-axis.

  int r = (SpinWheel.gz);

Then if the absolute value of this rotation is big enough, we add 1 to r_cum. In the original Rainbow_Chase example, the function millis() provided an
equivalent value for us. This bit of code ensures that the color of the LEDs only cycles when the device is moving. You can modify the threshold like in the other sketches for this lesson or change the number being added to r_cum to change how quickly the LEDs change color.

  if (abs(r) > 50) {
    r_cum += 1;
  }

We will have some fixed “delay” between the numbers controlling each LED’s color. Change this number! What happens?

  int r_delay = 20;

We will turn all of the LEDs on, but the color of each one of them will be governed by a slightly modified number.

  int r0 = r_cum % 250;
  int r1 = (r_cum+r_delay) % 250;
  int r2 = (r_cum+2*r_delay) % 250;
  int r3 = (r_cum+3*r_delay) % 250;

Here we finally set those colors. Let’s first turn on the large LEDs.

  SpinWheel.setLargeLED(0, colorWheel(r0));
  SpinWheel.setLargeLED(1, colorWheel(r1));
  SpinWheel.setLargeLED(2, colorWheel(r2));
  SpinWheel.setLargeLED(3, colorWheel(r3));
  SpinWheel.setLargeLED(4, colorWheel(r0));
  SpinWheel.setLargeLED(5, colorWheel(r1));
  SpinWheel.setLargeLED(6, colorWheel(r2));
  SpinWheel.setLargeLED(7, colorWheel(r3));

Now we can turn on the small LEDs.

  SpinWheel.setSmallLED(0, colorWheel(r0));
  SpinWheel.setSmallLED(1, colorWheel(r0));
  SpinWheel.setSmallLED(2, colorWheel(r1));
  SpinWheel.setSmallLED(3, colorWheel(r1));
  SpinWheel.setSmallLED(4, colorWheel(r1));
  SpinWheel.setSmallLED(5, colorWheel(r2));
  SpinWheel.setSmallLED(6, colorWheel(r2));
  SpinWheel.setSmallLED(7, colorWheel(r2));
  SpinWheel.setSmallLED(8, colorWheel(r3));
  SpinWheel.setSmallLED(9, colorWheel(r3));
  SpinWheel.setSmallLED(10, colorWheel(r1));
  SpinWheel.setSmallLED(11, colorWheel(r0));

Draw the image that was prepared in the previous lines.

  SpinWheel.drawFrame();
}