#include "FastLED.h"

#define LED_NUM 7
#define LED_PIN 8
CRGB leds[LED_NUM];

int buttonState = 0;

void setup() {
  Serial.begin(9600);
  pinMode(2, INPUT);
  FastLED.addLeds < WS2812, LED_PIN, GRB > (leds, LED_NUM);
  FastLED.setBrightness(200);
  FastLED.clear();
  
}

void loop() {
  Serial.println(buttonState);
  buttonState = digitalRead(2);
  if (buttonState == 1) {
    for (int i; i < LED_NUM; i ++) {
      leds[i].setHue(i * 255 / LED_NUM);
    }
    
    FastLED.show();
    delay(500);
  }
  if (buttonState == 0) {
    FastLED.clear();
    FastLED.show();
    delay(500);
  }
}