#include <Adafruit_NeoPixel.h>
#define PIN        2 
#define NUMPIXELS  64 
Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

#define trig 9
#define echo 8
void setup() 
{
  pixels.begin();
  pixels.clear();
  pixels.show();
  
  pinMode(trig , OUTPUT);
  pinMode(echo , INPUT);  
}

int check_distance ()
{
  digitalWrite(trig , LOW);
  delayMicroseconds(2);
  digitalWrite(trig , HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);
  long t = pulseIn(echo, HIGH);
  int distance = t * 0.017 ;
  return distance ;
}

void loop() 
{
  if (check_distance() > 200)
  {
    for (int ring = 0 ; ring < 4 ; ring++)
    {
      for (int led = 0 ; led < 16 ; led++)
      {
        pixels.setPixelColor(led+ring*16, pixels.Color(250, 255, 0));
        pixels.show(); 
        delay(50);
      }
    }
    pixels.clear();
    pixels.show(); 
    delay(100);  
  for (int ring = 3 ; ring >= 0 ; ring--)
    {
      for (int led = 15 ; led >=0 ; led--)
      {
        pixels.setPixelColor(led+ring*16, pixels.Color(250, 255, 0));
        pixels.show(); 
        delay(50);
      }
    }
    pixels.clear();
    pixels.show(); 
    delay(100);      
  }
}