Simply said the clock monitors your sleep phases with a sensor that is in a wrist band you need to wear at night. The clock then analyzes the best wake up time in a 30 minutes window before your set deadline. As you can see each sleeping phase is relatively short. REM and deep sleep phases are phases where you almost do not move in your sleep. When you move from one of theses phases into another your body moves more. The aXbo monitors this activity and calculates when it is best to wake you up.

From the description I guess the clock monitors if you move through a light sleep phase and if this happens in the 30 minute time window before the deadline it will wake you up. This sounds pretty simple but the results are promising. There is a review about the aXbo with more details on digitalreviews.net.

There is also an alternative to the aXbo called sleeptracker. This is a more compact solution because it is a wrist watch you can easily take everywhere. The advantage of the aXbo is that it has a variety of melodies to wake you up.

Both solutions aren’t cheap, the sleeptrackers ships for 149$ and the aXbo costs around 250$.

If you don’t want to pay money to wake up refreshed without feeling tired there are also other interesting tips. For example Vincent Cheung has written an article on how to wake up and feel better.

If you feel that there are not enough hours in a day you should consider a polyphasic sleeping cycle. This technique can reduce your sleep down to 2 hours a day. But be warned this technique needs a lot of discipline and should only be tried if you can completely manage time for yourself. If you’re seriously interested in polyphasic sleeping you should read Steve Pavlina’s blog. He is probably the one with the most experience in this area. Also he has very well documented his experience.