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user107850

Member since Jan 2020 • Last active Jun 2020
  • 2 conversations
  • 11 comments

Most recent activity

  • in Bangle.js
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    great!
    There is a bit of calibration to be done, so it's not just plug and play unfortunately. Happy to help!

  • in Bangle.js
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    Hello people!

    I've found a surprising way top count steps implemented in JS: https://github.com/alexgibson/shake.js/

    Some people did a validation study here: https://www.ncbi.nlm.nih.gov/pmc/article­s/PMC6219786/

    I have looked at the code and it's basically a threshold on the difference between two samples. I doubt this is generalisable. In fact, the authors of the paper had to manually calibrate the threshold on each phone and walking style.

    I'll leave it here as a curiosity.

  • in Other Boards
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    Hi fanoush,

    the time is meant to be in ms and it can be since the start of the system (the most common case) or since the start of the algorithm. If you don't have a clock, you can just feed a variable which you increment of +sampling_frequency each time, as you say yourself.

    It should be OK to reduce the type it to 32 bits, but there is no check when the clock is reset.

    Alternatively, you could just get rid of the timestamp altogether, but whenever time is used later in the algorithm, you need to assume that it has increased of a given period.

  • in Other Boards
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    A followup on this: we have a C implementation of the algorithm, in case anyone wants to import it: https://github.com/Oxford-step-counter/C­-Step-Counter

  • in Bangle.js
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    about step counting, if you want to take a lower level approach and embed it into the firmware, this is open source and validated: https://github.com/Oxford-step-counter/C­-Step-Counter

    There are some constants that need to be optimised because they depend on the actual hardware you use and the sampling frequency (we used 50Hz, but probably 10Hz would do anyway). See the instructions in the README. If anyone here wants to try including this in the BangleJS firmware, I'll be happy to help.

  • in Bangle.js
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    Hi all,
    our open source step counter has been ported to C and can be used in your project!
    Here is the repo: https://github.com/Oxford-step-counter/C­-Step-Counter

    There are some constants that need to be optimised because they depend on the actual hardware you use and the sampling frequency (we used 50Hz, but probably 10Hz would do anyway). See the instructions in the README. If anyone here wants to try including this in the BangleJS firmware, I'll be happy to help!

  • in Bangle.js
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    I'll check the thread, keep us posted. Our algorithm should be ready in a month or so. I'll keep you updated.

  • in Bangle.js
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    Hello,

    I've received my BangleJS a couple of days ago and I'm very happy about how easy it is to program. Unfortunately, for my applications, I would need a rather good accuracy for both steps and heart rate. Let's discuss step counting here.
    I noticed that the accelerometer does not include embedded step counting and that steps are computed by the Espruino firmware (here?). The algorithm unfortunately is very inaccurate: it waaaaaay over estimates my activity.

    Do you have plans in this regard? Maybe include an accelerometer with an embedded step counter in the next model (if any) ?

    If it helps, we are working on a C implementation of this algorithm specifically for microcontrollers and wearables. I can tell you when it's ready so maybe you could include it in the next firmware.

    Cheers.

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