When you are backpack hunting, what do you use to wake up before sunrise? I have one of the classic triathlon watches and set the alarm, but if my hand is down in the sleeping bag or under the pillow then I often sleep through it. More often than not I stress about over sleeping that I just continually wake up and check the time throughout the night. I tried the cell phone, but damn it's loud when the woods are quiet. Plus it drains the battery. What's your method of choice?