The SLEEPTRACKER watch is unique in that while it tells you the time and has a built-in alarm like every other digital watch, this one actually monitors your sleep and wakes you at the moment that your body would best adjust from moving from a sleeping state to being awake.
I didn’t post it at the time because I couldn’t figure out how it was supposed to work; however, today Tim May posted a followup comment in which he elaborates:
There’s an interview with the inventor of the Sleeptracker here. Turns out the sensory side of it’s simpler than you might expect — it just detects motion. I can imagine that working (although it’s not obvious that it would) and it’s certainly a lot simpler than somehow getting an [EEG] through someone’s wrist.
That sounds great, and the reviews seem to indicate that it works as advertised. Tim points out that there is also a group of students at Brown University are working on an EEG that you can wear to sleep.
I am like many other people who no longer wear a wristwatch now that I always carry a cell phone, so I’m not sure I could get in the habit of wearing one to sleep at night, but I can imagine this being great for afternoon naps, where I always worry about oversleeping and ending up feeling groggy the rest of the day. Assuming I can find the damn thing and put it on before I fall asleep!