#include <FastLED.h>

#define NUM_LEDS  28
#define LED_PIN   3

CRGB leds [NUM_LEDS];

void setup() {
  FastLED.addLeds<WS2812B, LED_PIN, GRB>(leds, NUM_LEDS);
  FastLED.setBrightness (255); 
      
}

void loop () {
  Routine1();
  Routine2();
  
  
}


//Sub-Routines below. 

void Routine1() {

  const uint32_t interval = 750UL; // half a 20BPM beat
  static unsigned long lastOffsetTime = 0;
  static uint32_t t0 = 0; // timebase
  static uint16_t phase = 0; // which segment of sine
  if(millis() - lastOffsetTime >= interval){
    lastOffsetTime += interval;
    t0 = millis() ; // update timebase
  }
  
  uint16_t sinBeat = beatsin16(20, 0, NUM_LEDS - 1, t0, phase);

  leds [sinBeat] = CRGB::Blue;

  fadeToBlackBy (leds, NUM_LEDS, 50);

  FastLED.show();

}




void Routine2() {

  const uint32_t interval1 = 1500UL; // half a 20BPM beat
  static unsigned long lastOffsetTime1 = 0;
  static uint32_t t01 = 0; // timebase
  static uint16_t phase1 = 32768/2; // which segment of sine
  if(millis() - lastOffsetTime1 >= interval1){
    lastOffsetTime1 += interval1;
    t01 = millis() ; // update timebase
  }
  
  uint16_t sinBeat1 = beatsin16(33.3, 0, NUM_LEDS - 1, t01, phase1);

  leds [sinBeat1] = CRGB::Red;

  fadeToBlackBy (leds, NUM_LEDS, 50);

  FastLED.show();

}