This is my first chance to use an iPhone with a motion co-processor running iOS 8 (in this case a new iPhone 6 with the barometer built in.)
Go to Health > Health Data > Fitness > Steps > Show All Data
I'm finding that even during continuous periods of walking (hundreds of steps without a break even for a second) the phone is nearly always grouping them into many, many entries but with only a few (it's usually 5) steps at a time.
Is anyone else seeing this? Is it normal? There's been the odd screenshot in the last month or two (from iPhone 5S owners using the iOS8 beta?) showing maybe a few hundred steps and then a few groups of 5, 10, 20 steps – which makes it much easier to read.
The total does seem extremely accurate – I've counted in my head a couple of times as I'm going along, and you can also leave the app running and see it add entries as you're walking along – incredibly it can still count perfectly if you walk but keep your hand really steady…
But I don't understand why the groups are so small?
There don't appear to be any other problems with my phone – the compass and the spirit level seem very precise, as does the GPS. I'm not sure how I'd test the barometer (although flights climbed is about right – outdoors anyway – indoors it logs I've climbed the stairs (2×7) about 50% of the time.)
I've tried with the phone in front and back pockets, I've tried walking faster and slower. The highest number of steps I've had is ~20 a few times when walking around indoors. I did wonder if was something to do with it wanting to group steps according to GPS position. Putting the iPhone into airplane mode doesn't make any difference either.
Best Answer
Yes - I see the same very small data sets from the 5s running iOS 8.
I also get over-estimates of my step count when running and walking yet somehow over the day, I believe the total counts are reliably the same small over-estimation of my actual effort.
My only conclusion is that the devices need to handle motion data from people with short legs, tall legs, stiff shoe soles, cushioned running soles, pavement and trail runs, etc...
I'm sure the engineers know that some class of people are over counted and another are under counted and my suspicion is that they are attempting to be as close to accurate for as large a group as possible and still work within the constraints on the firmware code size/complexity in the motion coprocessors and not drain the battery more than the allowed power budget for each device.
FWIW - the iPhone 6 is even better at estimating, still has lots of small data bursts logged to health app but still slightly over estimates my effort.