#include <Servo.h>

#define MOTION_SENSOR_PIN  22 // ESP32 pin GPIO22 connected to motion sensor's pin
#define SERVO_PIN          26 // ESP32 pin GPIO26 connected to servo motor's pin

Servo servo; // create servo object to control a servo

// variables will change:
int angle = 0;          // the current angle of servo motor
int lastMotionState;    // the previous state of motion sensor
int currentMotionState; // the current state of motion sensor

void setup() {
  Serial.begin(9600);                // initialize serial
  pinMode(MOTION_SENSOR_PIN, INPUT); // set ESP32 pin to input mode
  servo.attach(SERVO_PIN);           // attaches the servo on pin 9 to the servo object

  servo.write(angle);
  currentMotionState = digitalRead(MOTION_SENSOR_PIN);
}

void loop() {
  lastMotionState    = currentMotionState;             // save the last state
  currentMotionState = digitalRead(MOTION_SENSOR_PIN); // read new state

  if (currentMotionState==LOW) { // pin state change: LOW -> HIGH
    Serial.println("Motion detected!, rotating servo motor to 90°");
    servo.write(90);
  } else if (currentMotionState == HIGH) { // pin state change: HIGH -> LOW
    Serial.println("Motion stopped!, rotating servo motor to 0°");
    servo.write(0);
  }
}