Hello again Petr,
I executed your proposed experiment and it really worked fine. So the
alarm went off only after shaking the phone within the wake-up
period.
But during the last week when really being woken up by "Sleep as
Android" in the morning I still noticed that the alarm always started
at the beginning of the wake-up period (max. 2 minutes after). And
often I was sure (as sure as you can be in the morning ;-)) that I had
been sleeping quite deeply and calmly just before the alarm went off.
In fact, during all the time that I have been using the app (almost 4
weeks now) I have never been woken up later than 2 minutes after the
beginning of the smart wake-up period, no matter when in the morning
and how long I set the period (usually between 20min and 30min).
So I did another "experiment". I set set up another (not phone
related) alarm clock to 1 hour before the Sleep as Android smart wake-
up period started, with a wake-up period duration of 20 min. I went
out of bed and left the phone there, so it wouldn't be moved/shaken
etc. at all. And it still went off at the beginning of the smart wake-
up period, although this time I supposedly would have really been in
a deep-sleeping phase.
Do you have any ideas why this is so? Is there a way to log the actual
acceleration data at the sampling frequency so that one could see what
the phone detects before the alarm starts?
Thanks again for your good support and best regards,
Max