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???
03/12/12 11:57
Modified:
  03/12/12 11:59
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 		 #186597 - Fun with strain gauges
Responding to: ???'s previous message
I've been thinking along these lines for a bit. The trouble with a strain gauge on the pedal crank is getting it to pick up just the tangential force and none of the radial or axial force. Your useful working force puts the crank in bending, but as the pedal isn't on the crank axis you also introduce a twisting force on the crank. Most places I can think of for mounting a strain gauge will pick up both wanted and unwanted forces.

You don't need to know which gear you are in if you are measuring crank speed.

List of 61 messages in thread
TopicAuthorDate
bikey design challenge            01/01/70 00:00      
   Only 400W?            01/01/70 00:00      
      Its a bit different on the road            01/01/70 00:00      
         Brilliant idea in the bath            01/01/70 00:00      
            Might work            01/01/70 00:00      
               well...            01/01/70 00:00      
                  So you are yourself saying 400W is a bit low max scale            01/01/70 00:00      
                     O.K then 500 watts            01/01/70 00:00      
                        Battery            01/01/70 00:00      
            Fun with strain gauges            01/01/70 00:00      
         You sure?            01/01/70 00:00      
   nice ride            01/01/70 00:00      
      fanks            01/01/70 00:00      
   Sigma Rox 9.1...            01/01/70 00:00      
      Sigma fake            01/01/70 00:00      
         What do you expect for that price?            01/01/70 00:00      
            Head or tail wind? Or riding in a group or alone?            01/01/70 00:00      
               Way overcomplicating this            01/01/70 00:00      
                  Sensors            01/01/70 00:00      
                     how indeed            01/01/70 00:00      
                  Wrong - you are totally missing the drag factor            01/01/70 00:00      
                     Not at all.            01/01/70 00:00      
                        Real manufacturers haven't found your idea simple...            01/01/70 00:00      
                           Point made            01/01/70 00:00      
                           Some of your points are just wrong            01/01/70 00:00      
                              Sounds like you expect an infinite acceleration            01/01/70 00:00      
                                 Repeat post Ignore            01/01/70 00:00      
                                 I try for a constant power            01/01/70 00:00      
                                    Crank rpm - not back wheel rpm            01/01/70 00:00      
                                       I got the two confused            01/01/70 00:00      
                                          Bandwidth + return channel            01/01/70 00:00      
                        Oh dear, so many variable constants            01/01/70 00:00      
                  rocket science            01/01/70 00:00      
                     So don't ignore them            01/01/70 00:00      
                        Of course, it is...            01/01/70 00:00      
                           wireless            01/01/70 00:00      
                              Costs...            01/01/70 00:00      
                                 cost            01/01/70 00:00      
                                    Another problem            01/01/70 00:00      
                                       This was addressed earlier            01/01/70 00:00      
                                       Multiple strain gauges            01/01/70 00:00      
                                          Competitive bicycling            01/01/70 00:00      
                                             Pulse            01/01/70 00:00      
                                                If I had the power meter            01/01/70 00:00      
                                                   Normalizing with heart beats cancels some errors            01/01/70 00:00      
                                                      Just to get some data to look at            01/01/70 00:00      
                                                         Jez ?            01/01/70 00:00      
                                                            Oh Noes!!!!!!            01/01/70 00:00      
                                                            The plan is            01/01/70 00:00      
                                                               Brum doesn't HAVE mountains            01/01/70 00:00      
                                                                  Ah yes but no but            01/01/70 00:00      
                                                                  Actualy...            01/01/70 00:00      
                                                   If I had a power meter...            01/01/70 00:00      
                                                      Ive been testing things            01/01/70 00:00      
                                                         Well, no            01/01/70 00:00      
                                                            all very well thank you Steve            01/01/70 00:00      
                                                               Getting nasty            01/01/70 00:00      
                                                                  nasty ?            01/01/70 00:00      
                                 More time than money if access to machinery            01/01/70 00:00      
                                 Strain gauge elastic fixtures            01/01/70 00:00      
                           Sure            01/01/70 00:00      

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