#define ECHO_PIN 2
#define TRIG_PIN 3
#include <Servo.h>

Servo myservo; 
void setup() {
  myservo.attach(9); 
  Serial.begin(115200);
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
}

float readDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}

void loop() {
  float distance = readDistanceCM();
  Serial.print("Measured distance: ");
  Serial.println(readDistanceCM());
  if (distance < 100 ){
    digitalWrite(LED_BUILTIN, HIGH);
     myservo.write(180);
  }
  else{
    digitalWrite(LED_BUILTIN, LOW);
     myservo.write(0);
  }
 
  delay(100);
}