Novo

#define trigPin 5
#define echoPin 6
#include <Servo.h>

Servo myservo;

void setup() {
  Serial.begin (9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  myservo.attach(3);

}

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 <= 3)
  {
    myservo.write(0);
  }
  else(distance > 4);
  {
    myservo.write(90);
  }

  delay(300);
}