#include <Servo.h>
Servo myServo;
const int trigPin = 12;
const int echoPin = 11;
const int ledPinGreen = 6;
const int ledPinYellow = 5;
const int ledPinRed = 4;
long duration;
int distance;
int potVal;
int angle;

void setup()
{
  // put your setup code here, to run once:
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
pinMode(ledPinRed, OUTPUT);
pinMode(ledPinYellow, OUTPUT);
pinMode(ledPinGreen, OUTPUT);
myServo.attach(9);
Serial.begin(9600);
}

void loop()
{
  // put your main code here, to run repeatedly:
  digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distance= duration*0.034/2;
Serial.print("Distance: ");
Serial.println(distance);
if(distance <=10)
{
  digitalWrite(ledPinRed, HIGH);
  digitalWrite(ledPinYellow, LOW);
  digitalWrite(ledPinGreen, LOW);
  myServo.write(90);
}
if(distance > 10 && distance <=20)
{
  digitalWrite(ledPinRed, LOW);
  digitalWrite(ledPinYellow, HIGH);
  digitalWrite(ledPinGreen, LOW);
  myServo.write(180);
}
if(distance > 20)
{
  digitalWrite(ledPinRed, LOW);
  digitalWrite(ledPinYellow, LOW);
  digitalWrite(ledPinGreen, HIGH);
  myServo.write(180);
}
}