[LAU] A crazy idea

[Charles Henry]

On Thu, Mar 4, 2010 at 9:04 AM, Charles Henry <czhenry at gmail.com> wrote:
>> 1. A sensor that can measure my cadence. A simple magnet switch that
>> triggers once a revolution won't be enough to measure the cadence with
>> sufficient resolution, since my cadence is usually between 50 and 80
>> rpm. I would probably need to mount multiple magnets spaced equally
>> around the chainwheel and have a single sensor on the frame. Then I have
>> to get it to supply this information to my control program.
>
> Once per revolution is okay.  b/c what you've really asked for it not
> that the estimation be accurate to some threshold throughout the
> cycle, but that the output be smooth and continuous.

Let me also add that multiple magnets would definitely *help* the
process, if an F/V method were used.  My point was simply that any
rate of discrete events can be smoothly counted, if you don't care
about the accuracy between those events.  If you really need
resolution (like with control systems), go with a rotary encoder.

Chuck