/* LED "Color Organ" for Adafruit Trinket and NeoPixel LEDs.


Hardware requirements:

 - Adafruit Trinket or Gemma mini microcontroller (ATTiny85).

 - Adafruit Electret Microphone Amplifier (ID: 1063)

 - Several Neopixels, you can mix and match

   o Adafruit Flora RGB Smart Pixels (ID: 1260)

   o Adafruit NeoPixel Digital LED strip (ID: 1138)

   o Adafruit Neopixel Ring (ID: 1463)


Software requirements:

 - Adafruit NeoPixel library


Connections:

 - 5 V to mic amp +

 - GND to mic amp -

 - Analog pinto microphone output (configurable below)

 - Digital pin to LED data input (configurable below)


Written by Adafruit Industries.  Distributed under the BSD license.

This paragraph must be included in any redistribution.

*/

#include <Adafruit_NeoPixel.h>


#define N_PIXELS  60  // Number of pixels you are using

#define MIC_PIN    1  // Microphone is attached to Trinket GPIO #2/Gemma D2 (A1)

#define LED_PIN    0  // NeoPixel LED strand is connected to GPIO #0 / D0

#define DC_OFFSET  0  // DC offset in mic signal - if unusure, leave 0

#define NOISE     100  // Noise/hum/interference in mic signal

#define SAMPLES   60  // Length of buffer for dynamic level adjustment

#define TOP       (N_PIXELS +1) // Allow dot to go slightly off scale

// Comment out the next line if you do not want brightness control or have a Gemma

#define POT_PIN    3  // if defined, a potentiometer is on GPIO #3 (A3, Trinket only) 


byte

  peak      = 0,      // Used for falling dot

  dotCount  = 0,      // Frame counter for delaying dot-falling speed

  volCount  = 0;      // Frame counter for storing past volume data


int

  vol[SAMPLES],       // Collection of prior volume samples

  lvl       = 10,     // Current "dampened" audio level

  minLvlAvg = 0,      // For dynamic adjustment of graph low & high

  maxLvlAvg = 512;


Adafruit_NeoPixel  strip = Adafruit_NeoPixel(N_PIXELS, LED_PIN, NEO_GRB + NEO_KHZ800);


void setup() {

  memset(vol, 0, sizeof(vol));

  strip.begin();

}

void loop() {

  uint8_t  i;

  uint16_t minLvl, maxLvl;

  int      n, height;

  n   = analogRead(MIC_PIN);                 // Raw reading from mic 

  n   = abs(n - 512 - DC_OFFSET);            // Center on zero

  n   = (n <= NOISE) ? 0 : (n - NOISE);      // Remove noise/hum

  lvl = ((lvl * 7) + n) >> 3;    // "Dampened" reading (else looks twitchy)


  // Calculate bar height based on dynamic min/max levels (fixed point):

  height = TOP * (lvl - minLvlAvg) / (long)(maxLvlAvg - minLvlAvg);


  if(height < 0L)       height = 0;      // Clip output

  else if(height > TOP) height = TOP;

  if(height > peak)     peak   = height; // Keep 'peak' dot at top


// if POT_PIN is defined, we have a potentiometer on GPIO #3 on a Trinket 

//    (Gemma doesn't have this pin)

  uint8_t bright = 255;   

#ifdef POT_PIN            

   bright = analogRead(POT_PIN);  // Read pin (0-255) (adjust potentiometer 

                                  //   to give 0 to Vcc volts

#endif

  strip.setBrightness(bright);    // Set LED brightness (if POT_PIN at top

                                  //  define commented out, will be full)

  // Color pixels based on rainbow gradient

  for(i=0; i<N_PIXELS; i++) {  

    if(i >= height)               

       strip.setPixelColor(i,   0,   0, 0);

    else 

       strip.setPixelColor(i,Wheel(map(i,0,strip.numPixels()-1,30,150)));

    } 


   strip.show(); // Update strip


  vol[volCount] = n;                      // Save sample for dynamic leveling

  if(++volCount >= SAMPLES) volCount = 0; // Advance/rollover sample counter


  // Get volume range of prior frames

  minLvl = maxLvl = vol[0];

  for(i=1; i<SAMPLES; i++) {

    if(vol[i] < minLvl)      minLvl = vol[i];

    else if(vol[i] > maxLvl) maxLvl = vol[i];

  }

  // minLvl and maxLvl indicate the volume range over prior frames, used

  // for vertically scaling the output graph (so it looks interesting

  // regardless of volume level).  If they're too close together though

  // (e.g. at very low volume levels) the graph becomes super coarse

  // and 'jumpy'...so keep some minimum distance between them (this

  // also lets the graph go to zero when no sound is playing):

  if((maxLvl - minLvl) < TOP) maxLvl = minLvl + TOP;

  minLvlAvg = (minLvlAvg * 63 + minLvl) >> 6; // Dampen min/max levels

  maxLvlAvg = (maxLvlAvg * 63 + maxLvl) >> 6; // (fake rolling average)

}


// Input a value 0 to 255 to get a color value.

// The colors are a transition r - g - b - back to r.

uint32_t Wheel(byte WheelPos) {

  if(WheelPos < 85) {

   return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);

  } else if(WheelPos < 170) {

   WheelPos -= 85;

   return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);

  } else {

   WheelPos -= 170;

   return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);

  }

}