Kettler Stroker #20
Replies: 2 comments 8 replies
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thanks for the interest in this project! it's possible to simulate workouts on the computer that helps witht he calibration if you have the deltatime data of a recorded session. I have a few question I need to understand before I can help:
There is an inherent ussue with reed switches namely that they produce bounce. so we need to see what is being recorded by the mcu to deal with the potential bounce. |
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PR's are welcome thanks! I am less interested in the board profile and more in the rower profile:) you will need to include a few recorded session delta times with the proper naming (its in the test calibration folder) thrt includess the expected number if strokes so testing can happen when i change something. I tried the super mini and i measured a deep sleep current consumption of almost 1ma so I decided its not worth it. But the onboard charging circuit and the very tiny size is cool. I use now days a zero mini with AA battery: https://www.printables.com/model/1438697-waveshare-esp32-s3-zero-box it has half the feep sleep current. |
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I'm trying to create a configuration for my "Kettler Stroker" rowing machine.
The rower originally comes only with reed switches on the handle drive wheel, which is not optimal.
Luckily the rower is easy to disassemble, so I added a threadmill reed switch (it already came with the nice cable) and 4 small magnets on the flywheel.
This is what it looks like on the inside if anyone is interested:

For the brains I used a cheap "ESP32-S3 Super Mini" from AliExpress. (I can create a pull request for the PlatformIO config I made for it, if it's welcome.)

My testing contraption with a salvaged vape battery:
Now I'm stuck with the settings...

I was bored and CAD modeled the actual flywheel, which gave me a moment of inertia of 0.0265 kgm²
Kettler Stroker Flywheel.zip
For the "sprocket radius" I measured the belt pulley directly attached to the flywheel axis. It had an average radius of 1.6875 cm
The stroke count seems to work perfectly without tinkering with any other settings (besides the number of impulses per revolution).
The Force curve also seems plausible (not sure about the absolute values though).
But I can't get the distance and drag factor to work consistently. I guess something is wrong with my Drag factor filter settings...
Is there anything I can log to discover the proper settings to get this to work?
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