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Build your own Power Meter for $350 - Link to instructions
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I'd like to see someone reproduce his work / testing to confirm his design / pricing. Who's up for it?

http://keithhack.blogspot.ca/...complete-how-to.html

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Chicks are like Voltron, the more you can get, the better it is." -Tucker
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Re: Build your own Power Meter for $350 - Link to instructions [AlphaQ] [ In reply to ]
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The hard part in this kind of thing is the algorithm and software development. I wonder how comprehensive his code is. Would be cool to find out.
Last edited by: RZ: Jan 21, 13 19:29
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Re: Build your own Power Meter for $350 - Link to instructions [RZ] [ In reply to ]
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I was assured by many engineers in the first Stages PM thread that that that is the easy part. ;-)

Styrrell
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Re: Build your own Power Meter for $350 - Link to instructions [AlphaQ] [ In reply to ]
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That is seriously cool and I would love to have the smarts to do something like that, but I still think my quarq looks nicer! :-)
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Re: Build your own Power Meter for $350 - Link to instructions [AlphaQ] [ In reply to ]
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pretty cool, except in the end i would end up w/ a $350 pile of junk and possibly electrical burns


M.S. x 2; CSCS; ATC/LAT, Functional Movement Specialist, USA Track and Field Level 1
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Re: Build your own Power Meter for $350 - Link to instructions [styrrell] [ In reply to ]
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styrrell wrote:
I was assured by many engineers in the first Stages PM thread that that that is the easy part. ;-)

Yes, the hard part is making it look neat and expensive so you can sell it.

No one would ever buy a tangled mess of wires taped to a crankset.

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A Race for 2015: ITU Chicago
Coming from Canada

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Re: Build your own Power Meter for $350 - Link to instructions [AlphaQ] [ In reply to ]
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Wow. Engineers are SMART dudes.
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Re: Build your own Power Meter for $350 - Link to instructions [Clyde M.] [ In reply to ]
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Clyde M. wrote:
pretty cool, except in the end i would end up w/ a $350 pile of junk and possibly electrical burns

I have the skills to do it but I don't have the time due to training load... oh I also already have a SRM :)

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Chicks are like Voltron, the more you can get, the better it is." -Tucker
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Re: Build your own Power Meter for $350 - Link to instructions [AlphaQ] [ In reply to ]
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his pictures are in the small ring. I'm unimpressed.


seriously, this dude has some talent - or at least, determination.
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Re: Build your own Power Meter for $350 - Link to instructions [bradl016] [ In reply to ]
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bradl016 wrote:
his pictures are in the small ring. I'm unimpressed.

I was wondering if anyone else was going to pick up on that :)

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Chicks are like Voltron, the more you can get, the better it is." -Tucker
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Re: Build your own Power Meter for $350 - Link to instructions [AlphaQ] [ In reply to ]
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Hi, I noticed quite a bit of traffic to my blog from here and saw this discussion so figured I'd sign up and comment.

The small ring thing - There is just enough clearance to operate the prototype in the big ring, but because it's so close I haven't been doing much testing in the big ring. It's still just a prototype. I'm measuring the torque before the spider so it doesn't matter how many rings, teeth, shape, or size.

Both my drive side sensor and Stages are very similar in how they measure. My non-drive side is an ideal load cell though compared to anything out there making it highly accurate.

Thanks for your feedback!
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Re: Build your own Power Meter for $350 - Link to instructions [AlphaQ] [ In reply to ]
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Multiply the $350 by 2-3. Because as en EE, I know you're going to make a complete hash or literally set on fire the first attempt or two. Don't buy one of each part. Buy at least two of each. Potting/gluing/solder mistakes, etc. And as the author, you're guaranteed to have at least one short at one time or another.
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Re: Build your own Power Meter for $350 - Link to instructions [kwakeham] [ In reply to ]
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why not place your circuit board into the bottom bracket? that would clean it up and allow use of the big ring.

i like what youre doing, keep it up!




who's smarter than you're? i'm!
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Re: Build your own Power Meter for $350 - Link to instructions [veganerd] [ In reply to ]
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I tried that with my second prototype, V2, and it didn't work well as it blocks much of the wireless signals to the point where I was only getting an update once ever 3 - 4 seconds on my Garmin Edge 500 on the handle bars. I still have V2, it was shown on my blog. The antenna needs to be outside covered in a non-metal material.
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Re: Build your own Power Meter for $350 - Link to instructions [kwakeham] [ In reply to ]
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Interesting...this is almost exactly how Jim Meyer (Quarq) got started...

All it takes is a bit of instrumentation knowledege and the thought "How hard could it be?" <said in the voice of Top Gear's Jeremy Clarkson> ;-)



http://bikeblather.blogspot.com/
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Re: Build your own Power Meter for $350 - Link to instructions [kwakeham] [ In reply to ]
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kwakeham wrote:
Hi, I noticed quite a bit of traffic to my blog from here and saw this discussion so figured I'd sign up and comment.

The small ring thing - There is just enough clearance to operate the prototype in the big ring, but because it's so close I haven't been doing much testing in the big ring. It's still just a prototype. I'm measuring the torque before the spider so it doesn't matter how many rings, teeth, shape, or size.

Both my drive side sensor and Stages are very similar in how they measure. My non-drive side is an ideal load cell though compared to anything out there making it highly accurate.

Thanks for your feedback!

Welcome and thanks for signing up here! I saw your blog turn up on Hack a Day & thought this place would be quite interested in it as well so I posted it here. I'm actually quite suprised it's only had this many comments, the DIY Di2 TT shifters had several hundred and spawned a few replicas across the internet - If you're interested read here

The big ring comments are sort of an inside joke here, there's some "rules" be followed when taking pictures which you might see posters refer to, chain in the big ring, cranks at 90 degrees and valve stems upright etc. If you post pictures around here you're more likely to get people chipping in about how you've not cleaned your bike / patio / lounge than what the photo is actually about :)

Once again, thanks very much for signing up & I hope you stay around here as DIY geekery is very common here :)

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Chicks are like Voltron, the more you can get, the better it is." -Tucker
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Re: Build your own Power Meter for $350 - Link to instructions [kwakeham] [ In reply to ]
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Just wanted to take the opportunity to say kudos. Really great work. Are there any barriers to using the same setup with a carbon crank?
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Re: Build your own Power Meter for $350 - Link to instructions [kwakeham] [ In reply to ]
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Your videos and explanations are insanely cool. Please keep us updated on your progress.

“I am the light of the world. He who follows Me shall not walk in darkness, but have the light of life.” -Jesus

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Re: Build your own Power Meter for $350 - Link to instructions [steve.strong] [ In reply to ]
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steve.strong wrote:
Just wanted to take the opportunity to say kudos. Really great work. Are there any barriers to using the same setup with a carbon crank?

Without shielding there may be some static electricity interference.




who's smarter than you're? i'm!
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Re: Build your own Power Meter for $350 - Link to instructions [steve.strong] [ In reply to ]
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Thanks for the support from all.

I've heard Stages mention about "hysteresis" in carbon cranks. I haven't seen it personally but there are papers on it - I'll have to see if this is fully reversed forces or unidirectional. I'd like to see if for myself before I discount the possibility. I plan on seeing if I can source a used left arm of a Sram Force or Red crank to do some testing with before discounting it. I can read well enough but I tend to subscribe to Toyota's "Genchi Genbutsu" - go and see for yourself.


Sadly, I'm guessing the barriers to setting up and building a power meter is a little more difficult for people to swallow than building up Di2 TT shifters.


The blog is updated usually once or twice a week. Right now I'm trying to get my BT 2.0 to ANT+ translator working, though it's not high on the effort list.
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Re: Build your own Power Meter for $350 - Link to instructions [kwakeham] [ In reply to ]
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>It's still just a prototype.

You need to improve your attitude. It's ready for an Interbike booth and Spring official release announcement :).
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Re: Build your own Power Meter for $350 - Link to instructions [trail] [ In reply to ]
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Much appreciate the vote of confidence. I'm not quite sure, maybe a little more polish and work ;) Thanks
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Re: Build your own Power Meter for $350 - Link to instructions [nickwhite] [ In reply to ]
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I agree! I love that there are guys like you out there to keep me thinking and on my toes! please keep us all updated!

H*
Dream. Dig deep. Execute. Smile.
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Re: Build your own Power Meter for $350 - Link to instructions [Triheatherm] [ In reply to ]
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One of the big questions driving behind my project has been determining if there is a market for L/R measuring power meters. A friend of mine has been suggesting a "Kickstarter" Campaign to raise funding to accelerate development and convert my prototype to a more commercial product. Considering how large this forum is I'd love to hear some feedback on if people think this would be a good idea.

Thoughts? And thank you all in advance.
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Re: Build your own Power Meter for $350 - Link to instructions [kwakeham] [ In reply to ]
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I've got a spare Rival crank coming in the mail soon. I might just have to have a go at this.

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Jordan Oroshiba --- Roadie invading Triathlete space for knowledge access
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