#include <Servo.h>

Servo myservo;  // create servo object to control a servo
// twelve servo objects can be created on most boards
#define PIN_TRIG 3
#define PIN_ECHO 2
int pos = 0;    // variable to store the servo position

void setup() {
  Serial.begin(9600);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
}

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

  // Read the result:
  int duration = pulseIn(PIN_ECHO, HIGH);
  int tiempo = map(duration, 117, 23527, 10, 100);

  Serial.print("Distance in CM: ");
  Serial.println(duration / 58);
  Serial.print("Distance in inches: ");
  Serial.println(duration / 148);

  delay(1000);

  for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
    // in steps of 1 degree
    myservo.write(pos);              // tell servo to go to position in variable 'pos'
    delay(tiempo);                       // waits 15ms for the servo to reach the position
  }
  for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
    myservo.write(pos);              // tell servo to go to position in variable 'pos'
    delay(tiempo);                       // waits 15ms for the servo to reach the position
  }
}