How is the speed and rate determined?

[kronki]

I know that there's a sensor on the flywheel that runs through the wire and goes into the PM3, but what's the exact science behind it? How does the monitor calculate the splits and SPM from that? Does it use some formula for frequency detected by the flywheel to convert it from Hertz to watts, then to splits? Or is it something totally different?

Sorry if this seems like a random question, I'm an old retired guy interested in how millennial technology works. Especially with my Concept2 rower since it's what helped me stop ballooning.

[Citroen]

I hope you've got a good grounding in degree level physics & applied mathematics.
http://eodg.atm.ox.ac.uk/user/dudhia/ro ... meter.html

[jamesg]

but what's the exact science behind it

The sensor output (an impulse stream) lets the PM measure the maximum and minimum flywheel speeds and the times when these occur.
The loss of speed during recovery and the flywheel inertia give the Work done on the atmosphere by the fan during recovery between strokes.
This Work is then extrapolated to the full stroke and this, divided by overall stroke time, gives the rate of work (Power) in Watts, shown just after the pull ends.

This system made the erg (with a flywheel) perhaps the only exercise device that measures Power, simply and accurately.

SPM derives from 60/stroke time while pace (or speed) derives from a cube law where W = k V³. k is set to give the speed of a coxless four. Pace is 500/V.

[kronki]

Interesting, I think I understand the formulas the rower uses now. Thank you.

https://www.reddit.com/r/Rowing/comment ... minute_2k/

I did come across this link today. Do you understand how this worked? To me it looks like the poster connected false frequency signals into the PM3, which tricked the monitor into thinking the sensor was detecting a high rotational velocity in the fan, but I could be very wrong.

[Carl Watts]

Yes you can mess up the readings by having the monitor programmed to the wrong version of rower it is being used on.

There are other ways you can essentially "Cheat" and get better results, even verified results but for obvious reasons I'm not going to post that up here as there is enough cheating going on already.

Sufficient to say that Concept 2 has done a good job of minimizing this with the new model D/E rowers and monitors and the way the tach sensor works and the magnetics on the flywheel.

[Anth_F]

Cheatings a pathetic game.

[bojam]

No point in cheating ... WRs or country records and no one would believe an unheard of erger getting a record without a prior history of improvements in a club or one of the online competitions. Cheating for PBs/SBs you are only deluding yourself.