#include <FastLED.h>

#define LED_PIN     6
#define NUM_LEDS    3

CRGB leds[NUM_LEDS];

void setup() {

  FastLED.addLeds<WS2812, LED_PIN, GRB>(leds, NUM_LEDS);
  Serial.begin(9600);
}

void loop() {

  for (int i = 0; i < NUM_LEDS; i++) {
    leds[i] = CRGB ( 0, 0, 255);
    FastLED.show();
    delay(100);
  }
  for (int i = NUM_LEDS; i > 0; i--) {
    leds[i] = CRGB ( 255, 0, 0);
    FastLED.show();
    delay(100);
  }
  Serial.println("Ici");
}