#include <Servo.h>

int cm = 0;

int pos = 0;

Servo servo_9;

long readUltrasonicDistance(int triggerPin, int echoPin)
{
  pinMode(triggerPin, OUTPUT); 
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);
  pinMode(echoPin, INPUT);
  // Reads the echo pin, and returns the sound wave travel time in microseconds
  return pulseIn(echoPin, HIGH);
}

void setup()
{
  Serial.begin(9600);
  servo_9.attach(9, 1000, 2000);
}

void loop()
{
  // measure the ping time in cm
  cm = 0.01723 * readUltrasonicDistance(8, 7);
  Serial.print(cm);
  Serial.println("cm");
  delay(100); // Wait for 100 millisecond(s)
  if (cm >= 100){
     servo_9.write(pos);
    Serial.println("Closed");}
  else{
     servo_9.write(180);
    Serial.println("Open");}
}