While I was in college, I thought it would be really great if I could
arrange it so my alarm clock would wake me up when I was in a light
sleep rather than when I was in a deep sleep. I tried hooking up a
microphone to the computer near the bed to detect sound (I assumed I'd
be more likely to roll around and the like when in a light sleep) and
trigger based on that. There was too much ambient noise in a college
dorm environment and I gave up on the idea and I haven't had a
computer near my bed to try again since.
When I read about the href="http://www.sleeptracker.com/">Sleeptracker, I was naturally
very pleased, but at the same time skeptical. Their webiste had the
tone of a scam; light on specifics, high on claims. A while later,
Gear Live published a href="http://www.gearlive.com/index.php/news/article/sleeptracker_watch_review_03221147/">very
positive review and my interest was again piqued. I decided to order one.
It works. I wouldn't say I bounce out of bed, exicted and happy to
start the day with it. I'm simply not that much of a morning person.
However, I've not had that awful "please, not now" headache feeling I
often get when the alarm goes off. Of course, with a baby, the baby
often beats the alarm, in which case it's less effective.
It works by having an internal accelerometer which detects motion over
some period of time (it seems to require two movements in about a
minute, but that might not be quite right) and it considers such
movement a "light sleep" moment. It then ignores you for 8 minutes
and starts waiting for movement again. It's a simple and good system.
It doesn't require any reliable skin contact, it isn't sensitive to
ambient light, noise or even to my detection movement by someone else
I wish they'd put such an explanation on their web site that explains
this rather than mumbo jumbo like: "[it] continuously monitors signals
from your body that indicate". Yeah, singals like whether or not
you are moving. It would improve their credibility a lot. They should at
least put something in the manual. The fact that it uses an
accelerometer was apparent after playing with it for an hour or two.
The managing partner in the company stated it explicitly in href=http://www.gearlive.com/index.php/news/article/interview_with_lee_loree_sleeptracker_inventor_04131225/>this
interview, so it's not a big secret. Oh well.
It's a bit expensive ($150), but it does what it says and it does it
well. I'm glad I have mine.