#include <Servo.h>

#define pirPin 1
#define servoPin 9

Servo myservo;

void setup() {
  Serial.begin(9600);
  myservo.attach(servoPin);
  myservo.write(90);
  pinMode(pirPin, INPUT);
}

void loop() {
  int pir = digitalRead(pirPin);
  
  if (pir) {
    myservo.write(90);
    delay(100);
    myservo.write(50);
  }
  
}