[LAU] A crazy idea

Jonathan Gazeley jonathan.gazeley at bristol.ac.uk
Thu Mar 4 06:39:40 EST 2010

On 04/03/10 11:27, fons at kokkinizita.net wrote:
> On Thu, Mar 04, 2010 at 10:27:43AM +0000, Jonathan Gazeley wrote:
>> Yes - I have a cycle computer that can measure cadence. However, I
>> typically pedal between 60 and 90 rpm which means my reading would only
>> be available for sampling every 0.7 - 1.0s. It would work, but in the
>> space of one second my cadence can vary a lot if I'm accelerating so the
>> sound of the rising revs would be jumpy.
>> Also, if I suddenly stopped pedalling, it might take up to a second for
>> the sampler to register and kill the engine noise. I don't think it
>> would be a very satisfactory experience, which is why I was thinking of
>> mounting 10 or so magnets around the chainwheel, to be able to sample
>> the cadence every 0.1s.
> That would be a good rate. But for a realistic result you also
> need to measure the force you are putting on the pedals, or the
> chain tension - the noise of an engine depends very much on the
> amount of power it has to deliver.

Nick Copeland suggested simulating the force applied to the pedals by 
calculating the rate of change of the cadence. I reckon that might do 
the trick.
> I've been working on engine noise simulation - it's not very
> difficult unless you want to exactly simulate an existing car.

That sounds promising :)

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