Code

Arduino IDE

Open your Arduino IDE. If you are new to Arduino, check out this guide: Adafruit Arduino IDE Setup.

This sketch uses three libraries: the FastLED library, the Adafruit Circuit Playground microphone library, and the Adafruit Arduino Zero / Feather M0 I2S audio library. See FastLED.io for more information, the FastLED github, or visit their community on Reddit. You can learn more about Arduino libraries by reading this guide from Adafruit.

Download the Circuit Playground library if you haven't already done so. See the Circuit Playground Express guide to learn more about the board. In this sketch, we'll utilize some of the supporting libraries used by the Circuit Playground.

Code

Download the sketch in its entirety or take the following steps to ensure you have the right files for running the sketch.

Open a new sketch in your Arduino IDE & save it as a new folder. Find the folder just created by your new sketch. Copy & paste the following files from your Circuit Playground utilities folder into the newly created folder:

  • Adafruit_CPlay_Mic.cpp
  • Adafruit_CPlay_Mic.h
  • Adafruit_ZeroPDM.cpp
  • Adafruit_ZeroPDM.h

Plug the Adafruit Circuit Playground Express into your computer with a USB cable, verify and upload the following code.

Once you have uploaded your code, test it out on your Adafruit Circuit Playground Express. Although it will think that there are more LEDs attached, click through the modes and test the switch to make sure it all works. 

/*
HarnessBra by Amelia Tetterton as of 11/15/18

Summary:
  -Use the left button (D4) to cycle through some fun FastLED examples.
    -Create your own twinkles and adapt the BPM mode using FastLED palettes
    or create and name your own palettes!
  -Use the right button (D5) to activate the pretty vu meter from the Circuit Playground 
  pretty_meter example sketch, adapted for this strand.
  -Use the slide-switch (D7) to turn off the LEDs. This does not turn the board off.
*/
#include <FastLED.h>
#include "Adafruit_CPlay_Mic.h"

// Circuit Playground Setup----------------------------------------------------
#define CP_PIN      8         //CPX neopixels live on pin 8, CP live on pin 17
#define NUM_CP      10        //number of neopixels on the CP

const int switchPin = 7;      // the pin for the slideswitch
const int leftButtonPin = 4;  // the pin for the Left Button
const int rightButtonPin = 5; // the pin for the Right Button

bool switchState;
bool turnedOn;
bool PrevleftButton = false;         
bool PrevrightButton = false; 

bool leftButton = false;         
bool rightButton = false;  

// Strip Setup-----------------------------------------------------------------
#define LED_PIN     A1      //led strand is soldered to pin A1
#define NUM_STRIP   37      //number of LEDs called in my strand

#define LED_TYPE    WS2812B
#define COLOR_ORDER GRB
#define BRIGHTNESS  32  // 255 is full brightness
#define NUM_LEDS NUM_STRIP + NUM_CP

CRGB leds[NUM_LEDS];

CRGBPalette16 currentPalette;
CRGBPalette16 gPalette;
TBlendType    currentBlending;
uint8_t gHue = 0; // rotating "base color" used by many of the patterns
uint8_t BeatsPerMinute = 62; //for the FastLED BPM modes
int ledMode = 0;

#define NUM_MODES 9  // change this number if you add or subtract modes

#define UPDATES_PER_SECOND 100
#define SATURATION  255 // 0-255, 0 is pure white, 255 is fully saturated color
#define SPEED       100 // How fast the colors move. Higher numbers = faster motion
#define STEPS       3   // How wide the bands of color are. 
                        //1 = more like a gradient, 10 = more like stripes

// TWINKLE SETUP --------------------------------------------------------------
#define STARTING_BRIGHTNESS 255
#define FADE_IN_SPEED       80
#define FADE_OUT_SPEED      60
#define DENSITY             255    

// SOUND REACTIVE SETUP ------------------------------------------------------
Adafruit_CPlay_Mic mic;

// To keep the display 'lively,' an upper and lower range of volume
// levels are dynamically adjusted based on recent audio history, and
// the graph is fit into this range.

#define  FRAMES 8
uint16_t lvl[FRAMES],           // Audio level for the prior #FRAMES frames
         avgLo  = 6,            // Audio volume lower end of range
         avgHi  = 512,          // Audio volume upper end of range
         sum    = 256 * FRAMES; // Sum of lvl[] array
uint8_t  lvlIdx = 0;            // Counter into lvl[] array
int16_t  peak   = 0;            // Falling dot shows recent max
int8_t   peakV  = 0;            // Velocity of peak dot

// COLOR TABLES for pretty_meter animation -----------------------------------
const uint8_t PROGMEM
  reds[]   = { 0x9A, 0x75, 0x00, 0x00, 0x00, 0x65, 0x84, 0x9A, 0xAD, 0xAD },
  greens[] = { 0x00, 0x00, 0x00, 0x87, 0xB1, 0x9E, 0x87, 0x66, 0x00, 0x00 },
  blues[]  = { 0x95, 0xD5, 0xFF, 0xC3, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
  gamma8[] = { // Gamma correction improves the appearance of midrange colors
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
    0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x03, 0x03, 0x03, 0x03,
    0x03, 0x03, 0x04, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05, 0x05, 0x06,
    0x06, 0x06, 0x06, 0x07, 0x07, 0x07, 0x08, 0x08, 0x08, 0x09, 0x09, 0x09,
    0x0A, 0x0A, 0x0A, 0x0B, 0x0B, 0x0B, 0x0C, 0x0C, 0x0D, 0x0D, 0x0D, 0x0E,
    0x0E, 0x0F, 0x0F, 0x10, 0x10, 0x11, 0x11, 0x12, 0x12, 0x13, 0x13, 0x14,
    0x14, 0x15, 0x15, 0x16, 0x16, 0x17, 0x18, 0x18, 0x19, 0x19, 0x1A, 0x1B,
    0x1B, 0x1C, 0x1D, 0x1D, 0x1E, 0x1F, 0x1F, 0x20, 0x21, 0x22, 0x22, 0x23,
    0x24, 0x25, 0x26, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2A, 0x2B, 0x2C, 0x2D,
    0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
    0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x44, 0x45, 0x46,
    0x47, 0x48, 0x49, 0x4B, 0x4C, 0x4D, 0x4E, 0x50, 0x51, 0x52, 0x54, 0x55,
    0x56, 0x58, 0x59, 0x5A, 0x5C, 0x5D, 0x5E, 0x60, 0x61, 0x63, 0x64, 0x66,
    0x67, 0x69, 0x6A, 0x6C, 0x6D, 0x6F, 0x70, 0x72, 0x73, 0x75, 0x77, 0x78,
    0x7A, 0x7C, 0x7D, 0x7F, 0x81, 0x82, 0x84, 0x86, 0x88, 0x89, 0x8B, 0x8D,
    0x8F, 0x91, 0x92, 0x94, 0x96, 0x98, 0x9A, 0x9C, 0x9E, 0xA0, 0xA2, 0xA4,
    0xA6, 0xA8, 0xAA, 0xAC, 0xAE, 0xB0, 0xB2, 0xB4, 0xB6, 0xB8, 0xBA, 0xBC,
    0xBF, 0xC1, 0xC3, 0xC5, 0xC7, 0xCA, 0xCC, 0xCE, 0xD1, 0xD3, 0xD5, 0xD7,
    0xDA, 0xDC, 0xDF, 0xE1, 0xE3, 0xE6, 0xE8, 0xEB, 0xED, 0xF0, 0xF2, 0xF5,
    0xF7, 0xFA, 0xFC, 0xFF };

//Setup-----------------------------------------------------------------------

void setup() {
  Serial.begin(57600);  
  delay(3000); // 3 second delay for recovery
  
  //Add the onboard CP LEDs & the string of LEDs to create a single array
  FastLED.addLeds<LED_TYPE, CP_PIN,COLOR_ORDER>(leds, 0, NUM_CP).setCorrection(TypicalLEDStrip);
  FastLED.addLeds<LED_TYPE, LED_PIN,COLOR_ORDER>(leds, NUM_CP, NUM_STRIP).setCorrection(TypicalLEDStrip);
  
  FastLED.setBrightness(BRIGHTNESS);  
  pinMode(switchPin, INPUT_PULLUP); //set up the CP switch     
  pinMode(leftButtonPin, INPUT_PULLDOWN);  //set up the CP left button       
  pinMode(rightButtonPin, INPUT_PULLDOWN);  //set up the CP right button 
  currentBlending = LINEARBLEND; //FastLED blending
  for(uint8_t i=0; i<FRAMES; i++) lvl[i] = 256; //setup from sound reactive 
}

void loop() {
  
  PrevleftButton = leftButton;         
  leftButton = digitalRead(leftButtonPin);

  PrevrightButton = rightButton; 
  rightButton = digitalRead(rightButtonPin);
  
  switchState = digitalRead(switchPin);
  
  if (!switchState) {
    turnedOff();
  } else {
    turnedOn = true;
      
    if (!PrevleftButton && leftButton) {
      leftButtonPress();
    }
    if (!PrevrightButton && rightButton) {
      rightButtonPress();
    }
   
      static uint8_t startIndex = 0;
      startIndex = startIndex + 20; /* motion speed */
        
      switch (ledMode) {
        case 0:   rainbow();  break;
        case 1:   confetti(); break;        
        case 2:   RainbowBPM(); break; 
        case 3:   RainbowTwinkles(); break; 
        case 4:   sinelon(); break; 
        case 5:   juggle(); break;
        case 6:   PartyBPM(); break;
        case 7:   PartyTwinkles(); break;
        case 8:   LavaBPM(); break;
        case 9:   LavaTwinkles(); break; 

        case 99:  soundreactive(); break;       
      }
      FastLED.show();  
      FastLED.delay(1000/SPEED); 
      EVERY_N_MILLISECONDS(20) { gHue++; } // slowly cycle the "base color" through the rainbow
  }
}

void clearpixels() //clears all pixels, but does not put the board to sleep
{
    for (int i = 0; i < NUM_LEDS; i++) leds[i] = CRGB::Black; 
    FastLED.show();
}

void turnedOff()
{
   if (turnedOn){
   clearpixels();
    turnedOn = false;
  }
}

void leftButtonPress() 
{
  Serial.println("Left Button Pressed");
  clearpixels(); 
  ledMode++;
    if (ledMode > NUM_MODES){
    ledMode=0; 
  }  
}

void rightButtonPress() 
{
  Serial.println("Right Button Pressed");
  clearpixels();
  ledMode=99;  
}

void FillLEDsFromPaletteColors( uint8_t colorIndex)
{ 
  for (int i = 0; i < NUM_LEDS; i++) leds[i] = ColorFromPalette( currentPalette, colorIndex, BRIGHTNESS, currentBlending);
    colorIndex += STEPS;
}

// Twinkles!! -----------------------------------------------------------------
  // I've included twinkles for all of FastLEDs built-in palettes
  // Make your own palette (see ColorPalette example) to personalize twinkles

enum { GETTING_DARKER = 0, GETTING_BRIGHTER = 1 };

void OceanTwinkles()
{
  // Make each pixel brighter or darker, depending on
  // its 'direction' flag.
  brightenOrDarkenEachPixel( FADE_IN_SPEED, FADE_OUT_SPEED);
  
  // Now consider adding a new random twinkle
  if( random8() < DENSITY ) {
    int pos = random16(NUM_LEDS);
    if( !leds[pos]) {
      leds[pos] = ColorFromPalette( OceanColors_p, random8(), STARTING_BRIGHTNESS, NOBLEND);
      setPixelDirection(pos, GETTING_BRIGHTER);
    }
  }
}

void ForestTwinkles()
{
  brightenOrDarkenEachPixel( FADE_IN_SPEED, FADE_OUT_SPEED);
  if( random8() < DENSITY ) {
    int pos = random16(NUM_LEDS);
    if( !leds[pos]) {
      leds[pos] = ColorFromPalette( ForestColors_p, random8(), STARTING_BRIGHTNESS, NOBLEND);
      setPixelDirection(pos, GETTING_BRIGHTER);
    }
  }
}

void PartyTwinkles()
{
  brightenOrDarkenEachPixel( FADE_IN_SPEED, FADE_OUT_SPEED);
  if( random8() < DENSITY ) {
    int pos = random16(NUM_LEDS);
    if( !leds[pos]) {
      leds[pos] = ColorFromPalette( PartyColors_p, random8(), STARTING_BRIGHTNESS, NOBLEND);
      setPixelDirection(pos, GETTING_BRIGHTER);
    }
  }
}

void RainbowTwinkles()
{
  brightenOrDarkenEachPixel( FADE_IN_SPEED, FADE_OUT_SPEED);
  if( random8() < DENSITY ) {
    int pos = random16(NUM_LEDS);
    if( !leds[pos]) {
      leds[pos] = ColorFromPalette( RainbowColors_p, random8(), STARTING_BRIGHTNESS, NOBLEND);
      setPixelDirection(pos, GETTING_BRIGHTER);
    }
  }
}

void HeatTwinkles()
{
  brightenOrDarkenEachPixel( FADE_IN_SPEED, FADE_OUT_SPEED);
  if( random8() < DENSITY ) {
    int pos = random16(NUM_LEDS);
    if( !leds[pos]) {
      leds[pos] = ColorFromPalette( HeatColors_p, random8(), STARTING_BRIGHTNESS, NOBLEND);
      setPixelDirection(pos, GETTING_BRIGHTER);
    }
  }
}

void LavaTwinkles()
{
  brightenOrDarkenEachPixel( FADE_IN_SPEED, FADE_OUT_SPEED);
  if( random8() < DENSITY ) {
    int pos = random16(NUM_LEDS);
    if( !leds[pos]) {
      leds[pos] = ColorFromPalette( LavaColors_p, random8(), STARTING_BRIGHTNESS, NOBLEND);
      setPixelDirection(pos, GETTING_BRIGHTER);
    }
  }
}

void CloudTwinkles()
{
  brightenOrDarkenEachPixel( FADE_IN_SPEED, FADE_OUT_SPEED);
  if( random8() < DENSITY ) {
    int pos = random16(NUM_LEDS);
    if( !leds[pos]) {
      leds[pos] = ColorFromPalette( CloudColors_p, random8(), STARTING_BRIGHTNESS, NOBLEND);
      setPixelDirection(pos, GETTING_BRIGHTER);
    }
  }
}

void brightenOrDarkenEachPixel( fract8 fadeUpAmount, fract8 fadeDownAmount)
{
 for( uint16_t i = 0; i < NUM_LEDS; i++) {
    if( getPixelDirection(i) == GETTING_DARKER) {
      // This pixel is getting darker
      leds[i] = makeDarker( leds[i], fadeDownAmount);
    } else {
      // This pixel is getting brighter
      leds[i] = makeBrighter( leds[i], fadeUpAmount);
      // now check to see if we've maxxed out the brightness
      if( leds[i].r == 255 || leds[i].g == 255 || leds[i].b == 255) {
        // if so, turn around and start getting darker
        setPixelDirection(i, GETTING_DARKER);
      }
    }
  }
}

CRGB makeBrighter( const CRGB& color, fract8 howMuchBrighter) 
{
  CRGB incrementalColor = color;
  incrementalColor.nscale8( howMuchBrighter);
  return color + incrementalColor;
}

CRGB makeDarker( const CRGB& color, fract8 howMuchDarker) 
{
  CRGB newcolor = color;
  newcolor.nscale8( 255 - howMuchDarker);
  return newcolor;
}

// For illustration purposes, there are two separate implementations
// provided here for the array of 'directionFlags': 
// - a simple one, which uses one byte (8 bits) of RAM for each pixel, and
// - a compact one, which uses just one BIT of RAM for each pixel.

// Set this to 1 or 8 to select which implementation
// of directionFlags is used.  1=more compact, 8=simpler.
#define BITS_PER_DIRECTION_FLAG 1

#if BITS_PER_DIRECTION_FLAG == 8
// Simple implementation of the directionFlags array,
// which takes up one byte (eight bits) per pixel.
uint8_t directionFlags[NUM_LEDS];

bool getPixelDirection( uint16_t i) {
  return directionFlags[i];
}

void setPixelDirection( uint16_t i, bool dir) {
  directionFlags[i] = dir;
}
#endif

#if BITS_PER_DIRECTION_FLAG == 1
// Compact (but more complicated) implementation of
// the directionFlags array, using just one BIT of RAM
// per pixel.  This requires a bunch of bit wrangling,
// but conserves precious RAM.  The cost is a few
// cycles and about 100 bytes of flash program memory.
uint8_t  directionFlags[ (NUM_LEDS+7) / 8];

bool getPixelDirection( uint16_t i) {
  uint16_t index = i / 8;
  uint8_t  bitNum = i & 0x07;
  // using Arduino 'bitRead' function; expanded code below
  return bitRead( directionFlags[index], bitNum);
  // uint8_t  andMask = 1 << bitNum;
  // return (directionFlags[index] & andMask) != 0;
}

void setPixelDirection( uint16_t i, bool dir) {
  uint16_t index = i / 8;
  uint8_t  bitNum = i & 0x07;
  // using Arduino 'bitWrite' function; expanded code below
  bitWrite( directionFlags[index], bitNum, dir);
  //  uint8_t  orMask = 1 << bitNum;
  //  uint8_t andMask = 255 - orMask;
  //  uint8_t value = directionFlags[index] & andMask;
  //  if( dir ) {
  //    value += orMask;
  //  }
  //  directionFlags[index] = value;
}
#endif

// GLITTER -------------------------------------------------------------------

void rainbow() 
{
  // FastLED's built-in rainbow generator
  fill_rainbow( leds, NUM_LEDS, gHue, 7);
}

void rainbowWithGlitter() 
{
  // built-in FastLED rainbow, plus some random sparkly glitter
  rainbow();
  addGlitter(80);
}

void addGlitter( fract8 chanceOfGlitter) 
{
  if( random8() < chanceOfGlitter) {
    leds[ random16(NUM_LEDS) ] += CRGB::White;
  }
}

// FastLED Demo Reel ---------------------------------------------------------

void confetti() 
{
  // random colored speckles that blink in and fade smoothly
  fadeToBlackBy( leds, NUM_LEDS, 10);
  int pos = random16(NUM_LEDS);
  leds[pos] += CHSV( gHue + random8(64), 200, 255);
}

void juggle() {
  // eight colored dots, weaving in and out of sync with each other
  fadeToBlackBy( leds, NUM_LEDS, 20);
  byte dothue = 0;
  for( int i = 0; i < 8; i++) {
    leds[beatsin16( i+7, 0, NUM_LEDS )] |= CHSV(dothue, 200, 255);
    dothue += 32;
  }
}

void sinelon()
{
  // A colored dot sweeping back and forth, with fading trails
  fadeToBlackBy( leds, NUM_LEDS, 20);
  int pos = beatsin16( 13, 0, NUM_LEDS-1 );
  leds[pos] += CHSV( gHue, 255, 192);
}

// Various BPM examples -------------------------------------------------------
  // I've included BPM examples for all of FastLEDs built-in palettes
  // Make your own palette (see ColorPalette example) to personalize the BPM example

void PartyBPM()
{
  // colored stripes pulsing at a defined Beats-Per-Minute (BPM)
  CRGBPalette16 palette = PartyColors_p;//can adjust the palette here
  uint8_t beat = beatsin8( BeatsPerMinute, 64, 255);
  for( int i = 0; i < NUM_LEDS; i++) { //9948
    leds[i] = ColorFromPalette(palette, gHue+(i*2), beat-gHue+(i*10));
  }
}

void RainbowBPM()
{
  CRGBPalette16 palette = RainbowColors_p; //can adjust the palette here
  uint8_t beat = beatsin8( BeatsPerMinute, 64, 255); 
  for( int i = 0; i < NUM_LEDS; i++) { //9948
    leds[i] = ColorFromPalette(palette, gHue+(i*2), beat-gHue+(i*10));
  }
}

void CloudBPM()
{
  CRGBPalette16 palette = CloudColors_p; //can adjust the palette here
  uint8_t beat = beatsin8( BeatsPerMinute, 64, 255); 
  for( int i = 0; i < NUM_LEDS; i++) { //9948
    leds[i] = ColorFromPalette(palette, gHue+(i*2), beat-gHue+(i*10));
  }
}

void ForestBPM()
{
  CRGBPalette16 palette = ForestColors_p;//can adjust the palette here
  uint8_t beat = beatsin8( BeatsPerMinute, 64, 255);
  for( int i = 0; i < NUM_LEDS; i++) { //9948
    leds[i] = ColorFromPalette(palette, gHue+(i*2), beat-gHue+(i*10));
  }
}

void HeatBPM()
{
  CRGBPalette16 palette = HeatColors_p; //can adjust the palette here
  uint8_t beat = beatsin8( BeatsPerMinute, 64, 255); 
  for( int i = 0; i < NUM_LEDS; i++) { //9948
    leds[i] = ColorFromPalette(palette, gHue+(i*2), beat-gHue+(i*10));
  }
}

void LavaBPM()
{
  CRGBPalette16 palette = LavaColors_p; //can adjust the palette here
  uint8_t beat = beatsin8( BeatsPerMinute, 64, 255); 
  for( int i = 0; i < NUM_LEDS; i++) { //9948
    leds[i] = ColorFromPalette(palette, gHue+(i*2), beat-gHue+(i*10));
  }
}

void soundreactive() {
  uint8_t  i, r, g, b;
  uint16_t minLvl, maxLvl, a, scaled;
  int16_t  p;

  p           = mic.soundPressureLevel(10); // 10 ms
  p           = map(p, 56, 140, 0, 350);    // Scale to 0-350 (may overflow)
  a           = constrain(p, 0, 350);       // Clip to 0-350 range
  sum        -= lvl[lvlIdx];
  lvl[lvlIdx] = a;
  sum        += a;                              // Sum of lvl[] array
  minLvl = maxLvl = lvl[0];                     // Calc min, max of lvl[]...
  for(i=1; i<FRAMES; i++) {
    if(lvl[i] < minLvl)      minLvl = lvl[i];
    else if(lvl[i] > maxLvl) maxLvl = lvl[i];
  }

  // Keep some minimum distance between min & max levels,
  // else the display gets "jumpy."
  if((maxLvl - minLvl) < 40) {
    maxLvl = (minLvl < (512-40)) ? minLvl + 40 : 512;
  }
  avgLo = (avgLo * 7 + minLvl + 2) / 8; // Dampen min/max levels
  avgHi = (maxLvl >= avgHi) ?           // (fake rolling averages)
    (avgHi *  3 + maxLvl +1) /  4 :     // Fast rise
    (avgHi * 31 + maxLvl + 8) / 32;     // Slow decay

  a = sum / FRAMES; // Average of lvl[] array
  if(a <= avgLo) {  // Below min?
    scaled = 0;     // Bargraph = zero
  } else {          // Else scale to fixed-point coordspace 0-256*NUM_LEDS
      scaled = (256L * (NUM_LEDS)) * (a - avgLo) / (avgHi - avgLo);
      if(scaled > 256 * (NUM_LEDS)) scaled = (256 * (NUM_LEDS));
    }
  if(scaled >= peak) {            // New peak
    peakV = (scaled - peak) / 4;  // Give it an upward nudge
    peak  = scaled;
  }

  uint8_t  whole  = scaled / 256,    // Full-brightness pixels (0-10)
           frac   = scaled & 255;    // Brightness of fractional pixel
  int      whole2 = peak / 256,      // Index of peak pixel
           frac2  = peak & 255;      // Between-pixels position of peak
  uint16_t a1, a2;                   // Scaling factors for color blending

  for(i=0; i<NUM_LEDS; i++) {              // For each NeoPixel...
    if(i <= whole) {                 // In currently-lit area?
      r = pgm_read_byte(&reds[i]),   // Look up pixel color
      g = pgm_read_byte(&greens[i]),
      b = pgm_read_byte(&blues[i]);
      if(i == whole) {               // Fraction pixel at top of range?
        a1 = (uint16_t)frac + 1;     // Fade toward black
        r  = (r * a1) >> 8;
        g  = (g * a1) >> 8;
        b  = (b * a1) >> 8;
      }
    } else {
      r = g = b = 0;                 // In unlit area
    }
    // Composite the peak pixel atop whatever else is happening...
    if(i == whole2) {                // Peak pixel?
      a1 = 256 - frac2;              // Existing pixel blend factor 1-256
      a2 = frac2 + 1;                // Peak pixel blend factor 1-256
      r  = ((r * a1) + (0x84 * a2)) >> 8; // Will
      g  = ((g * a1) + (0x87 * a2)) >> 8; // it
      b  = ((b * a1) + (0xC3 * a2)) >> 8; // blend?
    } else if(i == (whole2-1)) {     // Just below peak pixel
      a1 = frac2 + 1;                // Opposite blend ratios to above,
      a2 = 256 - frac2;              // but same idea
      r  = ((r * a1) + (0x84 * a2)) >> 8;
      g  = ((g * a1) + (0x87 * a2)) >> 8;
      b  = ((b * a1) + (0xC3 * a2)) >> 8;
    }
       leds[i].r = pgm_read_byte(&gamma8[r]); 
       leds[i].g = pgm_read_byte(&gamma8[g]); 
       leds[i].b = pgm_read_byte(&gamma8[b]);
   }
   FastLED.show();

  peak += peakV;
  if(peak <= 0) {
    peak  = 0;
    peakV = 0;
  } else if(peakV >= -128) {
    peakV -= 2;
  }

  if(++lvlIdx >= FRAMES) lvlIdx = 0;

}
This guide was first published on Nov 21, 2018. It was last updated on Nov 21, 2018. This page (Code) was last updated on Nov 17, 2019.