#include <Adafruit_NeoPixel.h>
#define PIN 6
#define NUMPIXELS 10
Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);
// defines pins numbers
#define trigPin 11
#define echoPin 10
void setup() {
  pinMode(trigPin, OUTPUT); // trigPin as an Output
  pinMode(echoPin, INPUT); // echoPin as an Input
  Serial.begin(9600); // Starts the serial communication
  pixels.begin(); // INITIALIZE NeoPixel strip object
  pixels.clear(); // Set all pixel colors to 'off'
}
void loop() {
int distance = measureDistance();
  // Prints the distance on the Serial Monitor
  Serial.print("Distance: ");
  Serial.println(distance);
  set_colour(distance);
  delay(200);
}
int measureDistance(){
  long duration;
  int distance;
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  distance= duration*0.034/2;
  return distance;
}
void set_colour(int distance){
  int r,g,b,l;
  if(distance>200){
    r=0;
    g=255;
    b=0;
    l=10;
  } else {
    r=map(distance,0,200,255,0);
    g=map(distance,0,200,0,255);
    b=0;
    l=map(distance,0,200,1,10);
  }
  for(int i=0; i<10; i++){
    if(i<l)
      pixels.setPixelColor(i, pixels.Color(r, g, b));
    else
      pixels.setPixelColor(i, pixels.Color(0,0,0));
  }
  pixels.show();   // Send the updated pixel colors to the hardware.
}