#include <avr/sleep.h>

const int pirPin = 3; // PIR sensor pin connected to interrupt 1 (digital pin 3)
const int ledPin = 13; // LED pin

volatile bool motionDetected = false; // Flag to indicate motion detection
volatile bool keepLEDOn = false; // Flag to keep the LED on after 1 second
unsigned long lastMotionTime = 0; // Variable to store the time of the last motion detection
unsigned long lastMotionOffTime = 0; // Variable to store the time of the last motion-off event

void setup() {
  Serial.begin(9600); // Start serial communication
  pinMode(ledPin, OUTPUT); // LED pin as output
  pinMode(pirPin, INPUT_PULLUP); // PIR sensor pin as input with pull-up resistor
  attachInterrupt(digitalPinToInterrupt(pirPin), motionDetected_ISR, RISING); // Attach interrupt for rising edge
}

void loop() {
  if (motionDetected) {
    Serial.println("Motion detected!"); // Debug message
    digitalWrite(ledPin, HIGH); // Turn LED on
    lastMotionOffTime = millis(); // Record the time of motion detection
    while (millis() - lastMotionOffTime <= 1000) {
      // Keep the LED on for 1 second after motion detected
      // Check if motion still detected during this time
      if (digitalRead(pirPin) == LOW) {
        // Motion stopped, no need to keep the LED on
        keepLEDOn = false;
        break; // Exit the while loop
      }
      keepLEDOn = true; // Motion detected, keep the LED on
    }
    if (!keepLEDOn) {
      // Turn off the LED if no need to keep it on
      digitalWrite(ledPin, LOW); // Turn LED off
    }
    motionDetected = false; // Reset motion detection flag
  }

  // Check if 5 seconds have elapsed since the last motion detection
  if (millis() - lastMotionOffTime > 5000 && digitalRead(ledPin) == HIGH) {
    // If no motion detected for 5 seconds and LED is on, turn off the LED
    digitalWrite(ledPin, LOW); // Turn LED off
  }
}

void motionDetected_ISR() {
  motionDetected = true; // Set motion detection flag
  lastMotionTime = millis(); // Record the time of motion detection
}