Re: How do you measure SPEED on skates?

On Sat, 29 Nov 2003 19:23:25 GMT, FNGuy <[EMAIL PROTECTED]>
wrote:

>John Doe <[EMAIL PROTECTED]> wrote in 
>news:[EMAIL PROTECTED]:
>
>> You could measure wheel circumference, count wheel rotation, and then 
>> divide into time elapsed. 
>
>Hmmm, actually, with the low cost of optoelectronics and microprocessors, 
>and the fact that most skate wheels are SPOKED, that WOULD be a way to go.  

Such devices have been around for at least a decade.

If all wheels maintained constant contact with the ground, it might be
a reasonably accurate way to measure speed. But they're obviously not.
You also have to engineer a device that will be amazingly robust in
the face of all sorts of abuse that anything mounted to your skate
will get.

>That's my field--embedded real-time control... but I get enough of that at 
>work... otherwise I could make something that clips on the toe or heel and 
>shines through the wheel spokes... then you'd need an IR link to the wrist-
>mounted display readout... I smell PATENT--LOL! ;')

Several devices use GPS for measuring speed and distance. Timex has
such a device; I believe that Garmin came out with a
speed-and-distance-only device this year.

As you said in the first message of this thread, you could have a
widget that kicked out ultrasonic pulses and measured speed/distance
based on the doppler shift of the echoes. That has been done; someone
made a widget around 1988 for skiers. I just saw the description in
Outside magazine; I never saw any production units. It was
waist-mounted and really needed to have a heads-up display.

Given the push to drop the cost of GPS circuitry, I suspect that GPS
will be the way to go. You're welcome to patent something using
another measurement technique, but it'd probably as useful to skaters
as ... a hand lever to actuate a heel brake. After all, the existence
of a patent doesn't imply the existence of a market for the device.

--phil