trig_beatsin.ino

/*
  File: trig_beatsin

  By: Andrew Tuline

  Date: August, 2021

  Triggered breathing aka sine wave starting at 0, but using beatsin16() instead of a cos function, which starts at 0.

  This version was inspired by:

  https://old.reddit.com/r/FastLED/comments/p45t9r/how_to_restartreset_sinelon_effect_or_beatsin16/

  Although I didn't replicate their results, this seems to work well.

*/

#include <FastLED.h>

#define LED_PIN 12
#define NUM_LEDS 30
#define COLOR_ORDER GRB
#define LED_TYPE WS2812B
#define MAX_BRIGHTNESS 255

struct CRGB leds[NUM_LEDS];

void setup() {
  Serial.begin(115200);
  LEDS.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS);
  FastLED.setBrightness(MAX_BRIGHTNESS);
} // setup()


void loop() {
  trigbeat(10);
  FastLED.show();
} // loop()


void trigbeat(int bpm) {

  static uint32_t previousMillis;

  uint32_t currentMillis = millis();
  if (currentMillis - previousMillis >= bpm * 600) {                              // Reset after bpm.
    Serial.println("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX");
    previousMillis = currentMillis;
  }

  fadeToBlackBy(leds, NUM_LEDS, 16);
  uint16_t gPos = beatsin16(bpm, 0, NUM_LEDS - 1, previousMillis, 49152);         // bpm, lowest, highest,timebase, phase shift value.
  Serial.print(gPos); Serial.print(" "); Serial.println(previousMillis);
  leds[gPos] = CHSV(0, 255, 192);
} // trigbeat()