Change light color/brightness and sound frequency/volume based on the roll and pitch of the device.

Prop_Shield_Demo.ino

/**
 * Prop Shield Demo
 * Author: Shawn Hymel
 * Date: August 31, 2016
 * 
 * Description:
 *  Connect a single WS2812B to the LED output on the Prop Shield
 *  and a >2W speaker to the +/- speaker output. Attach the shield
 *  to a Teensy 3.2 and run the NXPMotionSense calibration sketch
 *  along with the MotionCal application to calibrate the IMU.
 *  
 *  Run this sketch. Rock the board back and forth (pitch) to 
 *  change the LED brightness and audio volume. Rock the board
 *  side to side (roll) to change the LED color and audio
 *  frequency.
 * 
 * License:
 *  Public Domain
 */

#include <FastLED.h>
#include <NXPMotionSense.h>
#include <Wire.h>
#include <EEPROM.h>

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>

// GUItool: begin automatically generated code
AudioSynthWaveformSine   sine1;          //xy=473,452
AudioMixer4              mixer1;         //xy=641,470
AudioOutputAnalog        dac1;           //xy=847,460
AudioConnection          patchCord1(sine1, 0, mixer1, 0);
AudioConnection          patchCord2(mixer1, dac1);
// GUItool: end automatically generated code

// Pins
const int LED_DATA_PIN = 7;

// Constants
const int NUM_LEDS = 1;

// Global variables
CRGB leds[NUM_LEDS];
NXPMotionSense imu;
NXPSensorFusion filter;

void setup() {

  // Initialize IMU and filter
  imu.begin();
  filter.begin(100);

  // Initialize LED
  FastLED.addLeds<WS2812B, LED_DATA_PIN, GRB>(leds, 1);

  // Turn on amp
  AudioMemory(20);
  dac1.analogReference(EXTERNAL); // much louder!
  delay(50);             // time for DAC voltage stable
  pinMode(5, OUTPUT);
  digitalWrite(5, HIGH); // turn on the amplifier
  delay(10);             // allow time to wake up
}

void loop() {
  
  float ax, ay, az;
  float gx, gy, gz;
  float mx, my, mz;
  float roll, pitch;
  uint8_t hue, val;
  long freq;
  float vol;

  // Read motion sensors and filter the results
  imu.readMotionSensor(ax, ay, az, gx, gy, gz, mx, my, mz);
  filter.update(gx, gy, gz, ax, ay, az, mx, my, mz);
  roll = filter.getRoll();
  pitch = filter.getPitch();

  // Change LED hue and brightness based on the roll and pitch
  hue = floatMap(roll, -90, 90, 0, 255);
  val = 255 - floatMap(pitch, -90, 90, 0, 255);
  leds[0] = CHSV(hue, 255, val);
  FastLED.show();

  // Change audio frequency and volume based on roll and pitch
  freq = floatMap(roll, -90, 90, 27, 4187);
  vol = 0.5 - floatMap(pitch, -90, 90, 0, 0.5);
  
  // Set frequency and volume for sound
  mixer1.gain(0, vol);
  sine1.frequency(freq);
  sine1.amplitude(1);
}

float floatMap(float x, 
               float inMin, 
               float inMax, 
               float outMin, 
               float outMax){

  // Set bounds
  if ( x < inMin ) x = inMin;
  if ( x > inMax ) x = inMax;
  
  return (x - inMin) * (outMax - outMin) / 
          (inMax - inMin) + outMin;
}