isn't there error in the power calculation based on the tire-trainer interface? how do you plan to calibrate the system?

overall, sounds really cool! i'm impressed, man. god, i'm (we're) lame...

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http://www.theninjadon.blogspot.com

"The bicycle riders drank much wine, and were burned and browned by the sun. They did not take the race seriously except among themselves." -- Ernest Hemingway, The Sun Also Rises

I must be a nerd because I think this is cool!

How did you get the powercurve onboard a chip? Is it an Altera type of device?

Any idea how accurate this will be? My guess is it will get you to +/- 15% maybe. Depends on how you derived the power data I guess. If you could calibrate it you would be set.

Keep us posted.

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Andrew

"When will i learn, people do not want to hurt but will spend $500.00 bucks to go four seconds faster." - randall t

I'm basically building a wireless version of what Kurt sells as a power meter for their fluid trainer. They have the power formula fit for their trainers posted on the website. The chip is a standard programmable computation chip from a company like Altera. The place I work has them lying around in the machine shop, so I swipped one with the foreman's permission.

I figure the best this thing can do is measure to within 10% of actual power. The largest errors introduced into the calculation come from the cubic term in P=Ax+Bx^3, so one is safe in ignoring any other sources of error.

You might consider a submitting this to Make Magazine [1] -- The first magazine devoted to digital projects. You'll be famous!! ;-)

[1] http://www.makezine.com/.