// Ex 7
#include <avr/sleep.h>  // Library for sleep modes

int buttonPin = 2;      // Pin connected to the push button
int ledPin = 13;        // Pin connected to the LED (built-in LED)

void setup() {
  pinMode(buttonPin, INPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  if (digitalRead(buttonPin) == HIGH) {
    Serial.println("Entering Power-Down Mode...");
    
    digitalWrite(ledPin, HIGH);  // Turn on the LED before sleep
    delay(500);                  // Short delay to see the LED on
    
    set_sleep_mode(SLEEP_MODE_PWR_DOWN);  // Set the power-down mode
    sleep_enable();                       // Enable sleep mode
    sleep_mode();                         // Enter sleep mode
    
    // The code will resume here after waking up from sleep
    sleep_disable();                      // Disable sleep mode after waking up
    
    Serial.println("Exiting Power-Down Mode...");
    digitalWrite(ledPin, LOW);   // Turn off the LED after waking up
  }
  
  // Continue other operations
  delay(1000);  // Regular operation delay
}