#include <FastLED.h>
#define PIN_LEDS 5
#define NBR_LEDS 3
CRGB leds[NBR_LEDS];

const uint8_t teintes[] = {0, 43, 85, 127, 170, 213, 255};
const uint8_t nbTeintes = sizeof teintes;

void setup() {
  FastLED.addLeds<WS2812B, PIN_LEDS, GRB >(leds, NBR_LEDS);
}

void loop() {
  static size_t teinte = 0;
  static uint8_t brightness = 0;
  static bool incrementation = true;

  fill_solid(leds, NBR_LEDS, CHSV(teintes[teinte], 255, brightness)); // 127 = vert, 255 totalement saturé
  FastLED.show();

  if (incrementation) {
    if (brightness == 255) {
      incrementation = false;
      brightness = 254;
    } else {
      brightness++;
    }
  } else {
    if (brightness == 0) {
      incrementation = true;
      brightness = 1;
      teinte = (teinte + 1) % nbTeintes;
    } else {
      brightness--;
    }
  }
  delay(1);
}