#include <NewPing.h>
#include <Servo.h>
#define trigPin 12
#define echoPin 13
#define MAX_DISTANCE 500
NewPing sonar(trigPin, echoPin, MAX_DISTANCE);
int greenLed = 3, redLed = 2;
int pos = 20;
Servo myservo;

void setup() {
  Serial.begin(115200);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, OUTPUT);
  pinMode(greenLed, OUTPUT);
  pinMode(redLed, OUTPUT);
  myservo.attach(9);
}

void loop() {
  int duration, distance, pos = 0, i;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance =(duration / 2) / 29.1;
  Serial.print(distance);
  Serial.println(" cm");

  if (distance <= 15) {
    digitalWrite(greenLed, LOW);
    digitalWrite(redLed, HIGH);
    myservo.write(180);
    delay(450);
    digitalWrite(redLed, LOW);
    myservo.write(90);
    delay(450);
    digitalWrite(redLed, HIGH);
    myservo.write(0);
    delay(450);
    digitalWrite(redLed, LOW);
    myservo.write(90);
  }

  else {
    digitalWrite(redLed, LOW);
    digitalWrite(greenLed, HIGH);
    myservo.write(90);
  }
  delay(450);
}