Arduino Low Power

/*************************************************** 
  Arduino Low Power processing
  
  How to use the low power mode with watchdoge timer on Arduino
  
  Based on:
  'Example 2: Arduino Power Down Sleep and CC3000 Shutdown
  
  Created by Tony DiCola (tony@tonydicola.com)

  Designed specifically to work with the Adafruit WiFi products:
  ----> https://www.adafruit.com/products/1469

  Adafruit invests time and resources providing this open source code, 
  please support Adafruit and open-source hardware by purchasing 
  products from Adafruit!

  Based on CC3000 examples written by Limor Fried & Kevin Townsend 
  for Adafruit Industries and released under a BSD license.
  All text above must be included in any redistribution.'
  
 ****************************************************/

#include <SPI.h>
#include <avr/sleep.h>
#include <avr/power.h>
#include <avr/wdt.h>

int sleepIterations = 0;
volatile bool watchdogActivated = false;

// Define watchdog timer interrupt.
ISR(WDT_vect)
{
  // Set the watchdog activated flag.
  // Note that you shouldn't do much work inside an interrupt handler.
  watchdogActivated = true;
}

void sleep()
{
  // Set sleep to full power down.  Only external interrupts or 
  // the watchdog timer can wake the CPU!
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);

  // Turn off the ADC while asleep.
  power_adc_disable();

  // Enable sleep and enter sleep mode.
  sleep_mode();

  // CPU is now asleep and program execution completely halts!
  // Once awake, execution will resume at this point.
  
  // When awake, disable sleep mode and turn on all devices.
  sleep_disable();
  power_all_enable();
}


void setup()
{
	doOtherSetupStuff()
	setupWatchdog()	
}

void doOtherSetupStuff()
{
	//Add code to do other setup stuff, like initialize ports, sensor etc.
}



void loop()
{
  // Don't do anything unless the watchdog timer interrupt has fired.
  if (watchdogActivated)
  {
    watchdogActivated = false;
    // Increase the count of sleep iterations and take a sensor
    // reading once the max number of iterations has been hit.
    sleepIterations += 1;
    if (sleepIterations >= MAX_SLEEP_ITERATIONS) {
      // Reset the number of sleep iterations.
      sleepIterations = 0;
	  doStuffWhenAwake()
    }
  }
  
  // Go to sleep!
  sleep();

}

void doStuffWhenAwake()
{
	//Add code to do when awake, e.g. sending sensor data 
}


void setupWatchdog()
{
// Setup the watchdog timer to run an interrupt which
  // wakes the Arduino from sleep every 8 seconds.
  
  // Note that the default behavior of resetting the Arduino
  // with the watchdog will be disabled.
  
  // This next section of code is timing critical, so interrupts are disabled.
  // See more details of how to change the watchdog in the ATmega328P datasheet
  // around page 50, Watchdog Timer.
  noInterrupts();
  
  // Set the watchdog reset bit in the MCU status register to 0.
  MCUSR &= ~(1<<WDRF);
  
  // Set WDCE and WDE bits in the watchdog control register.
  WDTCSR |= (1<<WDCE) | (1<<WDE);

  // Set watchdog clock prescaler bits to a value of 8 seconds.
  WDTCSR = (1<<WDP0) | (1<<WDP3);
  
  // Enable watchdog as interrupt only (no reset).
  WDTCSR |= (1<<WDIE);
  
  // Enable interrupts again.
  interrupts();
}