Split Beam timing device for track and field / athletics

[craig]

I would like to build a reliable timing device for timing my group of
athletes running over distances up to and including 60m and reduce the
cost of doing this to less than I could buy a commercial device for.

I would like a system that comprises two beams or.. a beam that is set
of by a cap gun and a beam at the finish.

The timing device will measure multiple athletes passing through the
second beam. - So that I can set of up to 8 athletes at once. (Or at
least 3)

I have a little experience in building electronic stuff and could
probably build it from components.

If any could lease help me by providing circuit diagrams/list of
components/where to get it that would be really helpful.

I hope I am not asking for the earth

Cheers

 

[craig]

Cheers for this I will definitely give that a try

 

[Terry Pinnell]

craig.burrow@lycos.co.uk (craig) wrote:

Terry,

Apologies for the vague spec info - I had assumed I would work from
first principles - I know how to read circuit diagrams, I can show
someone in a shop the diagram and ask them the tools I need, I can sit
at home and spend as long as it takes making the electronics.

So here goes

Spec Version 2:

I would like to build a reliable timing device for timing my group of
athletes running over distances up to and including 60m and reduce the
cost of doing this to less than I could buy a commercial device for.
Commercial devices of this type cost in excess of Ł1000 all in.

I would like a system that comprises two beams / photocell detectors
that set off a timing device upon a change in their resistance - ie.
someone crosses between the beam and the detector or the flash of the
cap gun is noticed by the photo cell.

- I saw this not as two requirements - The beam could be attatched to
the top of the cap gun and the flash would start the clock - Do you
think this is possible?

I need two seperate types of electronic equipment and information on
how they can be joined to make the final product -

A stop watch that can be started by another circuit. That has the
capacity to store and report mulitple lap times.

A trigger circuit which is one of a pair of photocells that detects
some kind of change to the light levels that they receive.

Please advise

Thank You

That's a *major* design, if done properly. There are many generous
contributors here and maybe one of them will prove me wrong, but
frankly I think you're being unrealistic to expect "circuit
diagrams/list of components/where to get it". You're asking for a
reliable design, a comprehensive set of schematics with accompanying
explanations and setup/calibrartion instructions - free of charge. And
that assumes you are able to spec your requirement *fully*. The
principles are straightforward enough - but the practical
implementation of a flexible, robust and accurate design is not.

BTW, you still haven't answered all the specific questions I listed
before. Indeed, you've raised *more* questions, at least in my mind!

I'd recommend you either buy a ready-made system, or seek professional
(paid) help.

--
Terry Pinnell
Hobbyist, West Sussex, UK