int trigPin = 13;
int echoPin = 11;
int servoPin = 6;

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

  Serial.begin(9600);
}

void loop() {

  // Send trigger pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);

  digitalWrite(trigPin, LOW);

  // Measure echo time
  long duration = pulseIn(echoPin, HIGH);

  // Calculate distance in centimeters
  float distance = duration * 0.034 / 2;

  // Display distance
  Serial.println(distance);

  // If object is closer than 7 cm
  if (distance < 7) {

    // Move servo to approximately 90 degrees
    digitalWrite(servoPin, HIGH);
    delayMicroseconds(1500);
    digitalWrite(servoPin, LOW);

    // Complete the 20 ms servo signal period
    delayMicroseconds(18500);
  }

  else {

    // Move servo to approximately 0 degrees
    digitalWrite(servoPin, HIGH);
    delayMicroseconds(1000);
    digitalWrite(servoPin, LOW);

    // Complete the 20 ms servo signal period
    delayMicroseconds(19000);
  }
}