Custom Capsense with FastLed and Low Pass filters

custom_capsense.ino

#include "FastLED.h"
#define NUM_LEDS 9
CRGB leds[NUM_LEDS];
#define PIXELLED 6
float minHue = 1.0f;
float maxHue = 1.0f;
float hue =0.0f;


#define resolution 8
#define mains 50 // 60: north america, japan; 50: most other places
#define refresh 2 * 1000000 / mains

void setup() {
  Serial.begin(115200);
  FastLED.addLeds<NEOPIXEL, PIXELLED>(leds, NUM_LEDS); 

  // unused pins are fairly insignificant,
  // but pulled low to reduce unknown variables
  for(int i = 2; i < 14; i++) {
    pinMode(i, OUTPUT);
    digitalWrite(i, LOW);  
  }

  for(int i = 8; i < 11; i++)
    pinMode(i, INPUT);

  startTimer();
}



void loop() {  
  //Serial.print(time(8, B00000001), DEC);
  //Serial.print(",");
  //Serial.print(time(9, B00000010), DEC);
  //Serial.print(",");
  //Serial.println(time(10, B00000100), DEC);
  int h = time(8, B00000001);
  hue += (h-hue) *0.05f;
  
  if ( (hue <minHue) && (hue > 1.0f) )
    minHue= hue;

  if (hue> maxHue)
    maxHue = hue;

  //me hago un comentario
  minHue += (hue-minHue)/(0.1f*minHue);
  maxHue -= (maxHue-hue)/(0.1f*maxHue);

  int hueMapped = cmap (hue, minHue, maxHue, 0, 255);

  
  Serial.print(minHue);
  Serial.print(",");
  Serial.print(maxHue);
  Serial.print(",");
  Serial.print(h);
  Serial.print(",");
  Serial.println (hue);

  FastLED.show();
  delay (20);
  
  for (int i=0;i<NUM_LEDS; i++){
    leds[i].setHue(hueMapped);
  }


} 

int cmap( int v, int _min, int _max, int _from, int _to){
  return map (constrain (v, _min, _max), _min, _max, _from, _to);
} 


long time(int pin, byte mask) {
  unsigned long count = 0, total = 0;
  while(checkTimer() < refresh) {
    // pinMode is about 6 times slower than assigning
    // DDRB directly, but that pause is important
    pinMode(pin, OUTPUT);
    PORTB = 0;
    pinMode(pin, INPUT);
    while((PINB & mask) == 0)
      count++;
    total++;
  }
  startTimer();
  return (count << resolution) / total;
}

extern volatile unsigned long timer0_overflow_count;

void startTimer() {
  timer0_overflow_count = 0;
  TCNT0 = 0;
}

unsigned long checkTimer() {
  return ((timer0_overflow_count << 8) + TCNT0) << 2;
}