#define echoPin 11
#define trigPin 12
const int PIN_RED   = 2;
const int PIN_GREEN = 3;
const int PIN_BLUE  = 4;
long duration, distance;
void setup() {
  Serial.begin (9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(PIN_RED,   OUTPUT);
  pinMode(PIN_GREEN, OUTPUT);
  pinMode(PIN_BLUE,  OUTPUT);

}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(5);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(5);
  digitalWrite(trigPin, LOW);
  delayMicroseconds(5);

  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2)/29.1;

  if(distance<=50){
    analogWrite(PIN_RED,   0);
    analogWrite(PIN_GREEN, 255);
    analogWrite(PIN_BLUE,  255);
    delay(500);
  }
  else{
    analogWrite(PIN_RED,   0);
    analogWrite(PIN_GREEN, 255);
    analogWrite(PIN_BLUE,  255);
    delay(250);
    analogWrite(PIN_RED,   255);
    analogWrite(PIN_GREEN, 0);
    analogWrite(PIN_BLUE,  256);
    delay(250);
    analogWrite(PIN_RED,   255);
    analogWrite(PIN_GREEN, 155);
    analogWrite(PIN_BLUE,  0);
    delay(250);
    analogWrite(PIN_RED,   0);
    analogWrite(PIN_GREEN, 0);
    analogWrite(PIN_BLUE,  255);
    delay(250);
    analogWrite(PIN_RED,   0);
    analogWrite(PIN_GREEN, 255);
    analogWrite(PIN_BLUE,  0);
    delay(250);
    analogWrite(PIN_RED,   255);
    analogWrite(PIN_GREEN, 0);
    analogWrite(PIN_BLUE,  0);
    delay(250);
    analogWrite(PIN_RED,   0);
    analogWrite(PIN_GREEN, 0);
    analogWrite(PIN_BLUE,  0);
    delay(250);
    
  }
  Serial.print(distance);
  Serial.println(" cm");
  delay(5);
}