Corona Wearable Distance Monitor

#include<Adafruit_NeoPixel.h>

#define ledPin D3
#define buzzerPin D2
#define echoPin D5
#define trigPin D6
#define ledNo 16

Adafruit_NeoPixel ring = Adafruit_NeoPixel(ledNo,ledPin,NEO_RGB+NEO_KHZ800);

int minDistance = 50, maxDistance = 80;

void setup() 
{
  pinMode(buzzerPin, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  ring.begin();
  for(int i = 0; i < ledNo; i++)
  {
    ring.setPixelColor(i,ring.Color(0,0,0));
  }
  ring.show();
}

void loop() 
{
  int distance = calcDistance();
  int ledsToGlow = map(distance, minDistance, maxDistance, ledNo, 1);
  if(ledsToGlow == 16)
  {
    digitalWrite(buzzerPin, HIGH);
  }
  else
  {
    digitalWrite(buzzerPin, LOW);
  }
  for(int i = 0; i < ledsToGlow; i++)
  {
    if(i < 6)
    {
      ring.setPixelColor(i,ring.Color(50,0,0));//g,r,b
    }
    else if(i >= 6 && i < 12)
    {
      ring.setPixelColor(i,ring.Color(50,50,0));//g,r,b
    }
    else if(i >= 12 && i < 16)
    {
      ring.setPixelColor(i,ring.Color(0,50,0));//g,r,b
    }
  }
  for(int i = ledsToGlow; i < ledNo; i++)
  {
    ring.setPixelColor(i,ring.Color(0,0,0));
  }
  ring.show();
  delay(150);
}

int calcDistance()
{
  long distance,duration;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration/29/2;
  if(distance >= maxDistance)
  {
    distance = maxDistance;
  }
  if(distance <= minDistance)
  {
    distance = minDistance;
  }
  return distance;
}