Recent content by dragilla

I like this idea - clever thinking :) Unfortunately the pedal is constructed differently. I was wrong about it from the beginning :( The pedal itself is threaded and is screwed into the crank. Still thinking about something different, but now the idea from the tutorial you pasted seems really...

Looks promising - thank you! :) The downside is... if the pull (strain) on the bolt is not equal across it and it probably isn't, then putting sensors on sides will produce "varying" results because the force to the pedal is applied at varying angles between the pedal and the crank (the bolt)...

That's too far from the power source I'm afraid (too much noise) plus it would require me to damage my frame! I don't even want to grind my crank! It's all expensive stuff... I've read somewhere that people make their own strain sensing bolts. But I don't know how to do it ... yet :)

Hehe jack, this would be tad inaccurate :) A much better solution to calculate power without actually measuring it would be to measure wind/elevation change/acceleration and then use that data to calculate power. But even that is still very inaccurate, does not take many things into account...

Would be great I someone else could say something. At the moment the risk of buying sensors just to check if it works seems to high. The ones I proposed at the beginning of this thread cost about $250 for a batch of 10 (can't buy a single piece) which is OK if you know it will work. Or maybe...

Unfortunately the bolt gauges are expensive and I don't have access to test them. Your BT idea should work, however I wanted something to work with my garmin.

Thank you for the link, CWatters! Do you agree with Doug on my idea? If calibration is the only issue here then I can live with that - I'm doing it for myself anyway. Ps: another idea just came to my mind - what If read the power even closer to the rider - I could put pressure sensors (mats)...

Are you sure about the tension staying the same in the bolt? I drew this little picture. Doesn't it work this way that there is a pivot point which causes the tension in the bolt to increase? http://prod.otn.pl/DSC_0213.JPG Thinking straight - if it was constant then any bolt would withstand...

So where would you put the strain gauge? In/on the chain? I don't understand. Anyway you haven't answered my question. Am I making some bad assumptions?

Hi, I'm a triathlete and a hobby constructor. I would like to build a power meter for my bike because the ones on the market are quiet expensive. The idea is to measure the power the rider puts into pedaling by measuring the tension between the pedal and the crank. They are connected with just...

Ok. Nevermind that. I can find a flat track, and use the dcm algorithm to produce a table: front_tire[speed_difference][acceleration] -> [angle] rear_tire[speed_difference][acceleration] -> [angle] This way I can teach my device new tires instead measuring them. Thanks.

Ok, I've pictured my tire (attachment 1 - DSC02097.jpg). Then I cut a fragment of it and put points on it (attachment 2 - unloaded.JPG). I've got. [0, 0], [11, 1], [24, 5], [36, 12], [50, 27], [61, 44], [67, 59] (I used the grid in gimp). What interpolation should I use to get the formula for...

Actually I am being creative... with my idea. I've already checked all the options that you write of. None of them fits my needs. Either too slow, too expensive or unpractical. The application is a traction control unit for a road racing bike. I do telemetry at the same time. I need to compare...

Thank you for your answer, That's what I ment. I want to measure the actual lean angle, not the theoretical one. Ok. This might be the best choice, so I will stick to it for now. I will be adding tires as needed. If I can determine the lean angle with accuracy of +/- .5 degrees then I'm...

Hello, First of all - I love this forum - so many interesting topics! My question is quite complicated - at least for me. My high level goal is to measure lean angle based on the difference of speeds between the front wheel of the bike vs the 'real speed' (let's just assume I have the...