void setup() 
{
#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 ()
}