// BY IRFXN.ISMAIL-ADAM IZZAT-ZAFRAN
#define MOTION_SENSOR_PIN 2 // The Arduino Nano pin connected to the motion sensor

int motion_state = LOW; // current state of the pin
int prev_motion_state = LOW; // previous state of the pin

void setup() {
  Serial.begin(9600); // Initialize the Serial communication
  pinMode(MOTION_SENSOR_PIN, INPUT); // Set Arduino pin to input mode
}

void loop() {
  prev_motion_state = motion_state; // store old state
  motion_state = digitalRead(MOTION_SENSOR_PIN); // read new state

  if (prev_motion_state == LOW && motion_state == HIGH) {
    // Motion detected
    Serial.println("Motion detected!");
    // TODO: turn on alarm, light, or activate a device here
  }
  else if (prev_motion_state == HIGH && motion_state == LOW) {
    // Motion stopped
    Serial.println("Motion stopped!");
  }

  delay(100); // small delay to avoid bouncing issues
}