From: Terry Pinnell
Subject: Re: Lap timer
Date: Mon, 02 Dec 2002 10:53:33 +0000
NNTP-Posting-Date: Mon, 2 Dec 2002 10:53:52 +0000 (UTC)
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"Paul V" wrote:
>I have a friend who does a bit of motorcycle racing and I'm looking for a
>timer which we can use on practice days.
>Doesn't have to be too fancy, but something simple to setup and reasonably
>accurate would be the go.
>A hand operated stopwatch just isn't accurate enough.
Presumably you've looked at commercial units, which I expect are
I've never tackled such a device, but I'd think it would include a
manually re-settable counter, with an LED or LCD display, frozen by a
signal from a sensor. That sensor could take several forms (as well,
of course, as a push-button in parallel, so that you could use it in
1. An interrupted IR beam.
For reliable operation, that might not be a trivial circuit, as it
would have to reject changing ambient light conditions (both natural
and artificial, if you expect to race at night). And it would
obviously only work for solo (or well-spaced) situations.
2. An interrupted pressure signal from a tube or hose stretched
tightly across the surface, like those you see in the road. Shares
some of the limitations of the above.
3. An RF-based system, with a small transmitter on the motor-bike, and
a receiver close to the finishing line, uniquely tuned to that
particular bike's frequency or transmission code.
Hobbyist, West Sussex, UK