#define trig 3
#define echo 2
#include <Adafruit_NeoPixel.h>
#define PIN 6 
#define NUMPIXELS 16
Adafruit_NeoPixel pixels (NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);
void setup() 
{
  pinMode (trig,OUTPUT);
  digitalWrite(trig,LOW);
  pinMode (echo,INPUT);
  Serial.begin(9600);
  pixels.begin();
}

void loop() 
{
  digitalWrite(trig,HIGH);
  delayMicroseconds(10);
  digitalWrite(trig,LOW);
  long t = pulseIn(echo,HIGH);
  float distance = t * 0.01715;
  Serial.println("Distance = " + String(distance)+"cm");
  delay(100);
  
    if (distance > 0 and distance < 100 )
    {
      for (int i=0; i<NUMPIXELS; i++)
      {
       pixels.setPixelColor(i, pixels.Color(255, 0, 0));
       pixels.show(); 
      }
    }
    if (distance > 100 and distance < 200 )
    {
      for (int i=0; i<NUMPIXELS; i++)
      {
       pixels.setPixelColor(i, pixels.Color(0, 0, 255));
       pixels.show(); 
      }
    }
    if (distance > 200 and distance < 300 )
    {
      for (int i=0; i<NUMPIXELS; i++)
      {
       pixels.setPixelColor(i, pixels.Color(0, 255, 0));
       pixels.show(); 
      }
    }
    if (distance > 300 and distance < 400 )
    {
      for (int i=0; i<NUMPIXELS; i++)
      {
       pixels.setPixelColor(i, pixels.Color(160, 32, 240));
       pixels.show(); 
      }
    }
}