#include <Servo.h>

const int trigPin = 9;
const int echoPin = 10;

const int detectionDistance = 20;

Servo myServo;
const int servoPin = 3;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  myServo.attach(servoPin);
  myServo.write(90); 

  Serial.begin(9600);
}

void loop() {
  long duration = getUltrasonicDistance();
  int distance = duration * 0.034 / 2; 

  Serial.print("Distancia: ");
  Serial.print(distance);
  Serial.println(" cm");

  if (distance <= detectionDistance) {
    sweepServo();
  } else {
    myServo.write(90); 
  }

  delay(100);
}

long getUltrasonicDistance() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  return pulseIn(echoPin, HIGH);
}

void sweepServo() {
  for (int pos = 0; pos <= 180; pos += 5) { 
    myServo.write(pos);
    delay(15);
  }
  for (int pos = 180; pos >= 0; pos -= 5) { 
    myServo.write(pos);
    delay(15);
  }
}