#include <Stepper.h>

#define STEPS 200 // steps per revolution for biaxial motor

Stepper fanMotor(STEPS, 9, 11, 10, 12);

#define PIR_PIN 2
#define LIGHT_PIN 8

unsigned long lastMotionTime = 0;
unsigned long timeout = 10000; 

bool systemActive = false;

void setup() {
  pinMode(PIR_PIN, INPUT);
  pinMode(LIGHT_PIN, OUTPUT);

  digitalWrite(LIGHT_PIN, LOW); 
  fanMotor.setSpeed(60); // Exhaust fan speed (RPM)

  Serial.begin(9600);
}

void loop() {
  int pirState = digitalRead(PIR_PIN);

  if (pirState == HIGH) {
    systemActive = true;
    lastMotionTime = millis();

    digitalWrite(LIGHT_PIN, HIGH); 

    fanMotor.step(15);

    Serial.println("Motion detected → Light ON, Fan Running");
  }
  if (systemActive==true){
    fanMotor.step(15);
  }

  if (systemActive && (millis() - lastMotionTime > timeout)) {
    systemActive = false;

    digitalWrite(LIGHT_PIN, LOW); 

    Serial.println("No movement → Light OFF, Fan OFF");
  }
}