#include <Servo.h>

#define pirsensorpin 18
#define servopin 19

Servo myservo;
void setup(){
  pinMode(pirsensorpin, INPUT);
  myservo.attach(servopin);
}

void loop(){
  bool isMotionDetected = digitalRead(pirsensorpin);
  if(isMotionDetected){
    myservo.write(90);
    delay(500);
    myservo.write(0);
  }
  else{
    myservo.write(0);
    delay(500);
  }
}