I am working with arduino pro mini 3.3V connecting with IR temperature sensors, openlog, a few RGB LEDs and a buzzer. I followed the example on sleep function here http://www.arduino.cc/playground/Learning/ArduinoSleepCode and put arduino to sleep when it is inactive for 8 seconds while it will wake when a interrupt button is pressed.
I attached a Li-Po battery 110mAh to it and after a day it run out of battery. I also found another example on battery saving at http://interface.khm.de/index.php/lab/experiments/sleep_watchdog_battery/ Will watchdog + sleep help to save more battery power ? I need to have it running without changing battery for at least 5 days.