Connecting a Concept2 Model B

[romanseidl]

I am trying to use ORM on a Concept2 Model B.

As I understand ORM wants to get just ON/OFF signals and the Concept2 is delivering the raw AC that comes from a coil next to the magnets on the flywheel. Because of this there is a need to transform the signal at leas to the right voltage using a resistor or an optocoupler. Is this correct?

If I would like to still use the original monitor, could I then use a reed or a hall sensor to get a measurement?

[romanseidl]

I now used some hall sensor ion a circuit board that delivers a digital output and it seems to work fine when I put the drag factor around 200.

Has anyone used the monitor with a Concept2 and has some more experience with the relevant parameters?

[JaapvanEkris]

I used it on a C2 RowErg, which has 6 magnets. Officially, the C2 Model B Flywheel inertia is 0.1001, and it has 3 magnets

[cassius-]

I am attempting this as well on a concept model B.

Could you please elaborate on how you use "some hall sensor ion a circuit board" to achieve this?

[romanseidl]

Great you are trying to do the same as I did!

The hardware is what you find, when you look for "KY-024" on AliExpress or somewhere similar. It's a curcuit board with an amplifier and AD IC, a potentiometer and a hall sensor. You can use the potentiometer to adjust sensitivity for a digital out. I guess I connected the power and the digital out to a digital in on the arduino. And I positioned the board such as that the hall sensor gets the magnets in the flywheel.

I still have some issues with the correct parameters for stroke detection. Didn't bother to fiddle around since I installed it but I suppose this would be easy to fix.

Do you need mote info? Or more images? Or my parameters? Just let me know.

[Abasz]

Do you have pigpio installed?

sudo apt install pigpio

as well as you need to run npm install

[cassius-]

Hi, sorry life threw some waves at me that were really hard to row out of ;)

My issue was resolved by two things:

• Me properly installing pigio
• Buying 3 packs of 3 of the KY-024 (third times the charm)

Its working great ! Thanks for the help.

[JaapvanEkris]

Any settings to share?

[cassius-]

I just have it set to Concept2_RowErg_modelB

rowerSettings: rowerProfiles.Concept2_RowErg_modelB

Seems to be a little behind the built in monitor.

[JaapvanEkris]

I just have it set to Concept2_RowErg_modelB

But there isn't such a profile in the official baselines? And adjusting is easy, just increase flyeheel-inertia a bit.

[JaapvanEkris]

Please note that when you use the V1Beta_Updates branch (see https://github.com/JaapvanEkris/openrowingmonitor/tree/v1beta_updates), which is the most solid implementation at the moment, we include a set of parameters for the C2 RowErg, which I test on almost a daily basis. The latest update (2 weeks ago) did change these settings as some code improved.

In theory, as the drive train and flywheel are kept the same, most settings should remain the same. In theory, only some parameters should change with respect to the original Model D/RowErg settings:
numOfImpulsesPerRevolution: 6 (Model C has 3),
minimumTimeBetweenImpulses: 0.005 (should double to 0.010 as the number of magnets halfed),
maximumTimeBetweenImpulses: 0.020 (should double to 0.040 as the number of magnets halfed),
flankLength: 12 (should half to 6 as the number of magnets halfed, and might even go lower as this setting is dominated by the noisy setup of the RowErg),
In practice this can have some knock-on effects on other parameters as the accuracy is a bit less.

If any of you can provide a raw trace of strokes (preferably with some basic data, and preferably around 20 to 200 strokes), I can help you guys tune this. I have designed the physics engine, done it for the RowErg and some other machines, so I guess I know what I'm doing. I have some spare time in the coming days (please note: NOT between Christmas and the first week of Jan), so I could pick it up.

[romanseidl]

Thanks! I would have time to have a look at this next week.

Mine and also @cassius- rowers are a model B. Yours is a model C or D? I somehow didn't understand this.

[JaapvanEkris]

Mine and also @cassius- rowers are a model B. Yours is a model C or D? I somehow didn't understand this.

I have a new RowErg, and I daily test the OpenRowingMonitor against the results of the PM5. In designing OpenRowingMonitor's physics engine, I deliberately isolated specific flywheel properties, so a situation where people add or remove magnets should be handled with relative ease. Concept 2 at some moment has changed the design of the sensor: the newer machines (Model D, RowErg) produce 18 Volt continuous and 18Volt sinoid signal with 6 periods per rotation. By using a optocoupler (see https://github.com/JaapvanEkris/openrowingmonitor/blob/v1beta_updates/docs/hardware_setup_Concept2_RowErg.md) we can feed that signal into the Raspberry Pi without blowing up ports. So, from ORM's perspective, a Model C would just be a RowErg with three magnets instead of six. So by design, you should be able to use the C2 RowErg as a starting point (with some modification).

It is the comparison with the PM5 that drives the improvements of the physics engine and OpenRowingMonitor behind the scenes. I also designed the 0.8.4 engine ground up, as well as the V1Beta, and while they were big improvements with respect to earlier physics engines, the look pale in comparison with the V1Beta_Updates engine. That is by far the most robust, reliable and easiest to configure to date. It is now structurally within 0.03% of the PM5 results (with over 3000K of rowing), so it is pretty close in my book, while still challenge me for improvement :). So if you haven't already, please use this newer engine as it is a huge improvement (and that is aside the serious functional improvements like a more flexible GUI and additional ANT+ and BLE profiles).

BTW: If you look for the tolerances of the RPi, they are listed here: https://raspberrypi.stackexchange.com/questions/3209/what-are-the-min-max-voltage-current-values-the-gpio-pins-can-handle

[JaapvanEkris]

Were you able to make any progress?

[cassius-]

Yep, I'm using the official baseline. Sadly I lost daily access to the Concept model B. I do have an exercise bike i'm trying to rig *openrowingmonitor* up to: Indoor Cycling Stationary Exercise Bike Chain Drive | Sunny Health and Fitness (sunnyhealthfitness.com) <https://sunnyhealthfitness.com/products/sunny-health-and-fitness-sf-b1203-chain-drive-indoor-cycling-trainer-exercise-bike> SF-B1203_manual.pdf (shopify.com) <https://cdn.shopify.com/s/files/1/0052/7043/7978/files/SF-B1203_manual.pdf> But I planned on creating a separate discussion after I take an honest swing at it. Thank you for the input. I plan on getting another PI to setup on the Concept model B and I'll tweak the flyeheel-inertia settings.

…

On Fri, May 17, 2024 at 11:18 AM Jaap van Ekris ***@***.***> wrote: I just have it set to Concept2_RowErg_modelB But there isn't such a profile in the official baselines? And adjusting is easy, just increase flyeheel-inertia a bit. — Reply to this email directly, view it on GitHub <#151 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACD22U35GXKZTLZPG7RVJJLZCYNTNAVCNFSM6AAAAAA3Z64U6KVHI2DSMVQWIX3LMV43SRDJONRXK43TNFXW4Q3PNVWWK3TUHM4TINZSGE2TO> . You are receiving this because you were mentioned.Message ID: ***@***.*** com>

[Abasz]

ORM will Not work with that bike. It's totally different physics. It will be able to count the number of rotations of the wheel but that's it.

To get metrics you need a power meter

[JaapvanEkris]

I agree with @Abasz here. Everything in ORM above flywheel.js is based on the rythem of a drive followed by a recovery. So you'd essentially need to rewrite the entire app to get rid of it. I know Concept2 uses the PM5 on their bikes, but it requires additional sensoring (i.e. they measure the resistance/drag lever position) and it also requires frequent calibration step to callibrate the drag with that drag lever position. And then still stuf like cadence is just weirdly defined for ORM.