You are reading a single comment by @HughB and its replies. Click here to read the full conversation.
  • @user107850 - were you involved with the Oxford Step counter project.

    I dont think @Gordon's attempt to follow the Oxford approach got off the ground.
    I think he introduced a low pass filter which had a lot of ringing.
    My main contribution has been testing. I have done litterally 100s of tests.
    I built prototypes in Javascript and finally checked in some C code changes.
    I identified the Oxford LPF filter as a better filter which is now used.
    I introduced a state machine which made things significantly more accuate.

    The actual C code for the Bangle step counter is at:
    https://github.com/hughbarney/Espruino/b­lob/master/libs/misc/stepcount.c

    If you were involved in the implementing the Oxford step counter I would be really interested to undertsand how the code works as I found it hard to follow after spending many hours looking at it. The event / queue driven structure of the code had me totally confused.

    I am also interested in what testing the Oxfrod team did to test non stepping activities like driving.
    150 steps (about 10 minutes of activity) is not enough to have confidence in a step counter. I could not find any test results for activities like driving, sleeping, sitting at a desk, typing etc etc. All of which should log very few steps per hour.

    but we need to set it up well, which means good data and a simple way to run the code.

    I have collected accelerometer logs for various activties. We have about 20 measured logs and these were calibrated against an AmizFit Bip which appears to be pretty accurate from the various tests I have done. When collecting the logs I wore the Amizfit Bip on the same wrist as the Bangle and recorded the steps recorded by both devices. The output in my above posts are from the test harness and the results are a good match for what gets measured in reality - so as a good simulation against algorithm changes.

    I would be really interested in talking with you if you know more about the Oxford approach.

About

Avatar for HughB @HughB started