#include <avr/io.h>
#include <util/delay.h>
#include <avr/sleep.h>
#include <avr/power.h> 
    
const int ledPin = 4; //1;

//#define F_CPU 16000000UL

void sleepNow() {
  {
//    BODCR |= (1<<BODS)|(1<<BODSE);       //Disable Brown Out Detector Control Register
    ACSR |= (1<<ACD);   //Analog comparator off
    ACSR = ADMUX = ADCSRA = 0;
  }

  WDTCR |= (1<<WDP3) ;      //Watchdog set for about 4 seconds
 
  // Enable watchdog timer interrupts
  WDTCR |= (1<<WDTIE);
  sei(); // Enable global interrupts
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);
  sleep_mode();
  sleep_disable();
}

void setup() {
  DDRB  = 0b000001; // all but PB0 INPUT, want to use PB0 ...
  PORTB = 0b000000; // all LOW
  
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, LOW);
}


void loop() {
  digitalWrite(ledPin, HIGH);
  _delay_ms(10);

  digitalWrite(ledPin, LOW);
 // _delay_ms(300);
  
  sleepNow();

}