#include <Servo.h>

// Define variables
int echopin = A0;
int trigpin = 7;
int Time;
int Distance;
Servo myservo;

void setup() {
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
  myservo.attach(11);
}

void loop() {
  digitalWrite(trigpin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigpin, HIGH);
  delayMicroseconds(10);
  Time = pulseIn(echopin, HIGH);
  Distance = Time * 0.0172;

  if (Distance > 30) {
    myservo.write(90);
  }
  else {
    myservo.write(0);
  }

  delay(100);
}