Countdown timer

I need help finding gear. I'm thinking of carrying a countdown timer to wake me up from sleeping. In my debilitated state it will be easier to user than trying to set my watch. Maybe some type of cooking timer?

Requirements:
- At least 3 hour max. with increments as small as 10 minutes.
- Easy to use
- As light as possible (of course :) )

Please sent any suggestions. Thanks!

P.S. Training is going well.

Training mileage

My first week of training passed without incident. It's roughly the mileage I normally hike each week just for fun so I wasn't expecting any problems. Below is the mileage I plan to hike each week for training.

February:
Week 1 - 16 - Done
Week 2 - 18
Week 3 - 20
Week 4 - 22

March:
Week 5 - 24
Week 6 - 27
Week 7 - 30
Week 8 - 33

April:
Week 9 - 36
Week 10 - 40
Week 11 - 44
Week 12 - 49
Week 13 - 54

May:
Week 14 - 60
Week 15 - 67
Week 16 - 74
Week 17 - 82

June:
Week 18 - 90
Week 19 - 50 mile days - 2
Week 20 - 100
Week 21 - 110

July:
Week 22 - 120
Week 23 - 40 mile days - 3
Week 24 - Sleep training
Week 25 - Sleep training
Week 26 - Sleep training

August:
Week 27 - Recover
Week 28 - Attempt (Actual week will vary)

I took my first step ...

... now all I have to do is continue putting one foot in front of the other.

I started my official training today. I walked about a mile to return a video and then over lunch I walked 4 miles with a 8lb. pack. It's one small bit of walking but a small bit more than yesterday.