dotstar-pixel-organ/dotstar-pixel-organ.ino

#include <Adafruit_DotStar.h>
#include <SPI.h>         // COMMENT OUT THIS LINE FOR GEMMA OR TRINKET

#define DEBUG true

#define NUMPIXELS 72 // Number of LEDs in strip
#define DATAPIN    4
#define CLOCKPIN   5
#define DECAYFACTOR 0.95
Adafruit_DotStar strip = Adafruit_DotStar(
                           NUMPIXELS, DATAPIN, CLOCKPIN, DOTSTAR_BRG);

#define MICPIN   A0 // microphone
//Turns out QUIETPIN is not that important
//#define QUIETPIN A1 // potentiometer to determine "quiet" level (no output below this)
#define LOUD 768    // constant. Higher than that means compress to 0..255
#define BUFFSIZE 96 // at least NUMPIXELS!
#define AVGSIZE 5
#define MILLI_AMNESIA 23 // How much to "falsely remeber" current value as history (1..999)
int rawBuff[BUFFSIZE];
int notHighBuff[BUFFSIZE];
int lowBuff[BUFFSIZE];
int index, minLow, maxLow, minMid, maxMid, minHigh, maxHigh, dynRange;

#define rawLow(i) (lowBuff[i])
#define rawMid(i) (notHighBuff[i]-lowBuff[i])
#define rawHigh(i) (rawBuff[i]-notHighBuff[i])
#define normLow(i) map(rawLow(i),minLow,maxLow,0,dynRange)
#define normMid(i) map(rawMid(i),minMid,maxMid,0,dynRange)
#define normHigh(i) map(rawHigh(i),minHigh,maxHigh,0,dynRange)

unsigned long lastTime, thisTime;

void setup() {
  if (DEBUG) {
    Serial.begin(230400);
  }
  lastTime = millis();
  index = 0;
  strip.begin(); // Initialize pins for output
  strip.show();  // Turn all LEDs off ASAP
  for (int i = 0; i < BUFFSIZE; i++) {
    rawBuff[i] = notHighBuff[i] = lowBuff[i] = 512;
  }
}


void loop() {
  thisTime = millis();
  unsigned long rate = 1000 / max(thisTime - lastTime, 1);
  rawBuff[index] = analogRead(MICPIN);
  notHighBuff[index] = 0;
  int nextIndex = (index + 1) % BUFFSIZE;
  for (int i = nextIndex + BUFFSIZE - AVGSIZE; i % BUFFSIZE != nextIndex; i++) {
    notHighBuff[index] += rawBuff[i % BUFFSIZE];
  }
  notHighBuff[index] /= AVGSIZE;
  lowBuff[index] = (notHighBuff[index] + notHighBuff[(index + BUFFSIZE - AVGSIZE) % BUFFSIZE]) / 2;
  minLow = minMid = minHigh = 1024;
  maxLow = maxMid = maxHigh = -1;
  long pseudoRaw = rawBuff[index] * MILLI_AMNESIA;
  long pseudoNotHigh = notHighBuff[index] * MILLI_AMNESIA;
  long pseudoLow = lowBuff[index] * MILLI_AMNESIA;
  for (int i = 0; i < BUFFSIZE; i++) {
    rawBuff[i] = (long(rawBuff[i] * long(1000 - MILLI_AMNESIA) + pseudoRaw)) / 1000;
    notHighBuff[i] = (long(notHighBuff[i] * long(1000 - MILLI_AMNESIA) + pseudoNotHigh)) / 1000;
    lowBuff[i] = (long(lowBuff[i] * long(1000 - MILLI_AMNESIA) + pseudoLow)) / 1000;
    minLow =   min(minLow, rawLow(i));
    minMid =   min(minMid, rawMid(i));
    minHigh =  min(minHigh, rawHigh(i));
    maxLow =   max(maxLow, rawLow(i));
    maxMid =   max(maxMid, rawMid(i));
    maxHigh =  max(maxHigh, rawHigh(i));
  }
  int quiet = LOUD / 5; // was: map(analogRead(QUIETPIN), 0, 1024, 0, LOUD * 7 / 8);
  dynRange = constrain(
               map(max(maxLow, max(maxMid, maxHigh)) - min(minLow, min(minMid, minHigh)),
                   quiet, LOUD, 0, 255),
               0, 255);

  int buffIndex = index;
  float ledFactor = 1.0;
  for (int i = 0;  i < NUMPIXELS; i++) {
    uint32_t rgb = uint32_t(
                     ((uint32_t(float(normHigh(buffIndex)) * ledFactor) << 8) +
                      uint32_t(float(normMid(buffIndex)) * ledFactor) << 8) +
                     uint32_t(float(normLow(buffIndex)) * ledFactor));
    strip.setPixelColor(NUMPIXELS - i, rgb);
    buffIndex = (buffIndex + BUFFSIZE - 1) % BUFFSIZE;
    ledFactor *= DECAYFACTOR;
  }
  strip.show();
  if (DEBUG) {
    Serial.print(dynRange);
    Serial.print(' ');
    Serial.print(normLow(index));
    Serial.print(' ');
    Serial.print(normMid(index));
    Serial.print(' ');
    Serial.print(normHigh(index));
    Serial.print(' ');
    Serial.print('\n');
  }
  index = nextIndex;
  lastTime = thisTime;
  delay(1); // this is considered good manners ;)
}