#include <Servo.h>
Servo myservo;  // create servo object to control a servo
int potpin = 0;  // analog pin used to connect the potentiometer
int val;    // variable to read the value from the analog pin
int trigger = 12;
int echo = 13;
int led = 2;
long duration = 0;
int cm = 0;
int inch = 0;
void setup() {
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
  Serial.begin(9600);
  pinMode(trigger, OUTPUT);
  pinMode(echo, INPUT);
  pinMode(led, OUTPUT);
}

void loop() {
  val = analogRead(potpin);            // reads the value of the potentiometer (value between 0 and 1023)
  val = map(val, 0, 1023, 0, 180);     // scale it to use it with the servo (value between 0 and 180)
  myservo.write(val);                  // sets the servo position according to the scaled value
  delay(15);                           // waits for the servo to get there
  // put your main code here, to run repeatedly:
  digitalWrite(trigger, LOW);
  digitalWrite(trigger, HIGH);
  digitalWrite(trigger, LOW);

  duration = pulseIn(echo, HIGH);
  cm = duration*0.034/2;
  inch = duration*0.0133/2;

  if (inch < 50){
    digitalWrite(led, HIGH);
  } else {
    digitalWrite(led, LOW);
  }

  if (inch < 100 ) {
    Serial.print("Inches: ");
    Serial.println(inch);
    Serial.print("Cm: ");
    Serial.println(cm);
  }
  delay(500);
}