>From: Mark Andy <mark@sccaprepared.com>
>Any reason not to make the reflectors a bit bigger to ease timing light
>setup?
If you make them bigger, then you will allow more of a misalignment, which
can change the effective length of the course (not by much, but we measure
in thousanths). We put the small reflector on a larger background to help
aiming (see description below).
>From: Travis Dixon <travisd@tubas.net>
>One thing I've seen suggested to to make a "backboard" out of the
>reflective material they use for road signs that you can use just for
>alignment purposes.
We used some sign material and found that it was nowhere near as reflective
as the industrial-grade reflectors from JACircuits. We are able to get an
effective range of more than 40 feet with the small reflectors.
Originally, we put sign material on a piece of Masonite inside the box at
the back of a milk crate and the range wasn't all that good. Then we
mounted the JACircuits reflector in the middle of that, and had no problems
with range. Having the large board behind the reflector makes the job of
aiming a lot easier. I would use a non-refletive background against which
the laser beam would be most visible (i.e. Red would be a bad color
choice).
The milk crate also has a piece of Masonite inside up against the top to
keep rain off the reflector. Our timers are in similar boxes. In high-wind
situations, we put some weight in the box. A plastic-coated barbell weight
works good. Also, the milk crates absorb some shock if they get hit,
protecting the timer head.
Steve Miller
FCSCC timing chair
|