I've tried it for a week or so; didn't work for me. The accelerometer did pick up on my movements, though.

Also, I think putting my iPhone at the corner of my bed is a little risky. When sleepily reaching for your phone in the corner of the bed it's easy to drop it, scratch it against the wall, etc. Even when you're generally a careful person; it's going to wake you up 300 days a year, and it has to go wrong only once.

I'm hoping sleepmate does a better job.

Yes, you place the phone on the corner of your mattress. So when you move in bed, it can detect that because your mattress shakes. And how much you move in bed is related to your sleep cycle (it's called Actigraphy). I tried it last night and i remember i woke up twice and checked the time. The graph produced by the app matches these times. The alarm simply went off at the set time, but it says that the app needs 2 nights to calibrate to your bed and your sleep cycle, so i can't say how well that works.

> There are quite a few critical reviews that say it doesn't.

Can you show the reviews URL for the rest of us?

I'm curious if anyone knows how this type of solution would work if there is more than one person sleeping in your bed.

Wouldn't two people in the same bed be pretty likely to not have synchronized sleep cycles? Or would they be synchronized? Anyone know about this?

From the FAQ:

"How well does Sleep Cycle work with 2 people sharing a bed?

Our experience is that it works very well. Normally your body will "block" the movement of the other person and the iPhone will not detect that movement. You can test this yourself by using the test function in Sleep Cycle."

After about two weeks of usage: It seems to work very well, at least in the sense that my movements are registered correctly. I would estimate that it causes a noticeable difference waking up about 1/3 of the time.

I use SleepCycle. Can't tell you if it is a sham or not-- it seems to work and seems to reflect my subjective assessments of my nights sleep