I started to wear the Pebble at 00:00 last night, when the steps were reset to 0. Misfit accurately tracked my sleeping time: 5:58 sleep, 2:10 deep sleep, about 200 steps but this also included some movement before I actually went to bed at about 01:00. I put the app in the background on purpose to see if it works and kept my usual watchface displayed.
- a Factory Reset after updating to Pebble firmware 2.6 fixed my issue with Misfit resetting step count (it has something to do with the firmware messing up with the watch storage / settings saving). This was also happening with the UP app. Maybe this is also the problem with resetting the sleep log that you have.
- I guess you are supposed to wear the watch while you sleep especially if you want information about "deep sleep" (I am guessing "deep sleep" means a a total duration of continuous, longer periods of non-movement). Otherwise, if you put the watch on your desk before you go to sleep the app will probably think you went to bed, and it would only be accurate if you actually did and also pick the watch up right after you wake up. No magic there, it's just a sensor. Another factor they could take into account would be time of day, but I don't think the app uses that.
- I don't think it "learns" anything, for me it worked from the first day (night) of use
@ChrisFarwell, @AdrianMilliner - the accelerometer detects any movement, not just what looks like "steps". My guess is it keeps a history of the last 5 minutes in 3 movement types: "heavy", "light" and "steps". If you are idle, you're certainly not perfectly still and you have some sort of movement, at least in a 5 minutes period. If it detects only "light" movement after 5 minutes of perfect stillness, I guess it will still count the time as sleep. If it detects "heavy" movement and the movement persists fox x seconds / a minute, I guess it will discard the last 5 idle minutes it presumed it was sleep as it doesn't count as sleep anyway (I don't think it counts as a power nap either), and actually record any apparent "steps" it detected during that period as "walking" / normal movement while awake.
- for your first comment, did you take off your watch at any time during the day (sorry if this is a dumb question)? They could detect if the watch sits flat on a desk and not at your wrist and discard that as sleep, and I hope the app does that. Or at least they should provide an option as how to record that time for the times we don't wear the watch at night (and maybe another one for "charging" time, although I personally charge the watch on weekends during the day).
- as for the sleep walking, it's normal for it to count movement in your sleep as steps, it's just an accelerometer on your wrist. I also had a 100-150 "steps" recorded and I'm pretty sure I didn't get up during the night, but definitely moved a bit before I fell asleep and maybe during sleep. On11 also counted some "steps" during the night. I wore the watch at night on purpose, because I was curious how much I move without me remembering and that roughly indicates the quality of my sleep. Turns out some nights I'm pretty agitated :)
As a disclaimer, I am no dev, and everything I said above is based on pure guess. Some light from the developers about the actual algorithm would be greatly appreciated.