#include <Adafruit_NeoPixel.h>

#define PIXEL_PIN 8
#define PIXEL_COUNT 20
#define PIN_TRIG 3
#define PIN_ECHO 2

Adafruit_NeoPixel strip = Adafruit_NeoPixel(PIXEL_COUNT, PIXEL_PIN, NEO_GRB + NEO_KHZ800);
// Parameter 1 = number of pixels in strip,  neopixel stick has 8
// Parameter 2 = pin number (most are valid)
// Parameter 3 = pixel type flags, add together as needed:
//   NEO_RGB     Pixels are wired for RGB bitstream
//   NEO_GRB     Pixels are wired for GRB bitstream, correct for neopixel stick
//   NEO_KHZ400  400 KHz bitstream (e.g. FLORA pixels)
//   NEO_KHZ800  800 KHz bitstream (e.g. High Density LED strip), correct for neopixel stick

void setup() {
  //setup ring
  strip.begin();
  strip.setBrightness(255);

  //setup ultrasonic
  Serial.begin(115200);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);  
}

void loop() {
  digitalWrite(PIN_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG, LOW);

  int duration = pulseIn(PIN_ECHO, HIGH);
  int distance = duration / 58;

  strip.clear(); //clear ring

  //ring distance
  if (distance < 404){
    for(int i=0; i<3; i++){
      strip.setPixelColor(i, strip.Color(218, 247, 166)); 
    }
  }
  if (distance < 330){ 
    for(int i=3; i<6; i++){
      strip.setPixelColor(i, strip.Color(255, 195, 0)); 
    }
  }  
  if (distance < 260){
    for(int i=6; i<9; i++){
      strip.setPixelColor(i, strip.Color(255, 87, 51)); 
    }
  }
  if (distance < 190){
    for(int i=9; i<12; i++){
      strip.setPixelColor(i, strip.Color(199, 0, 57)); 
    }
  } 
  if (distance < 120){
    for(int i=12; i<(14); i++){
      strip.setPixelColor(i, strip.Color(144, 12, 63)); 
    }
  } 
  if (distance < 70){ 
    for(int i=14; i<16; i++){
      strip.setPixelColor(i, strip.Color(88, 24, 69)); 
    }
  }
  strip.show();
}