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Electric or Human Eyes: Take your Pick
by John Shreffler

When they needed to go a distance, our great grandparents traveled by horse
and buggy. Some groups in our society still do that, but there are
drawbacks in terms of convenience, time, and energy. Most travelers have
found that the automobile or airplane just does a better job.

History of Finish Line Judging

Likewise, when pinewood derby racing appeared on the scene some fifty years
ago, the only way to determine the winner was to use the human eyeball.
Some groups still do that, perhaps for reasons of frugality, or nostalgia.
But there are drawbacks. Pinewood derby races are typically very close, and
it is often impossible to eyeball the winner, much less the finishing order.
Often, the audience (invariably the parents) will get into the act, and
dispute the official's call. And this is where things break down. Some
officials stand firm and risk looking like they are partial or stubborn.
Other officials might respond by allowing re-runs on contested races. But
once this happens, typically, almost all races have to be re-runs. Tales
abound of poor parenting examples, and perhaps the worst part is that
children with less aggressive parents are at a disadvantage. The time wasted
and the hard feelings generated are a serious drawback to the intent of this
otherwise fine youth activity.

Technology of varying degrees has been tried over the years. One early
low-tech approach was to place a paper cup on each lane. The idea was that
the flying paper cups would be easier to interpret than the position of the
bumper of a blur. Not much help, however. A higher tech approach was to
use a video cam-corder, and play each race back in slow-motion. Not all
that much help either, and all it usually did was to drag things out for
hours longer than anyone expected.

The basic problem of pinewood derby racing is that the parents demand
accuracy in judging. But the kids just want to see their cars moving on
down that hill. What a dilemma!

Technology, as it often does, has come a long way. These days, it is
possible to run a pinewood derby race every thirty seconds, with complete
accuracy, no ties, no parental second-guessing, and no angry words. How is
this possible? Ask any organization that has made the big switch to
electronic finish lines. They are instant believers and only wonder what
took them so long to see the light.

Who am I?

Hi. I am John Shreffler, and I make an electronic finish line called 'The
Judge'. I got started in this adventure many years ago when my son was in
Cub Scouts, and as fate would have it, I got 'volunteered' out of the
audience to be a human judge. I saw immediately that this was no job for
amateurs. The next year, I came to the derby with a crude homebuilt optical
finish line and it was an immediate hit. I saw the possibilities and went
for it. Against my wife's cautions, I gambled the investment in parts, and
the rest of the story is history.

Finish Line Options

Naturally, I must keep very aware of the pros and cons of the various finish
lines available on the market. Options and features abound, and they can be
confusing to the uninitiated. Which are essential to a smooth race? Which
are nice to have and why?

To answer these questions and to give you a better idea of what to look for
when selecting a finish line, I have listed the various features and options
available for finish lines. I have also categorized them by whether they
are essential or just nice to have.

Essential Features

Accuracy - At the finish line, a difference of one-thousandth of a
second (0.001) equates to about 1/8 inch. Thus, to eliminate ties and to
achieve the most accurate results, the internal accuracy of the finish line
should be at least one ten-thousandth of a second (0.0001).

Dependable Sensors - Most finish lines use infrared sensors, which
trigger when the front edge of the car blocks the overhead light source.
This method is quite dependable and is immune to reflections, flash
photography, etc.. An alternate method is track sensors which are triggered
when the front edge of the car physically contacts a sensor. Depending on
the quality of the switches, this method can also be dependable, but some
prefer to not have the car physically touched when passing through the
finish line.

Finish Line Read Out - It is important for the audience to immediately
see the results of the race. For smaller events, a read-out on the finish
line works well (for larger events, consider a computer interface with the
results displayed on video monitors or projected onto a screen). Some
models offer flashing lights to indicate first, second, and third place;
while other models use numeric readouts. Either will work, but the flashing
light method can be seen and interpreted from a distance and from a wide
angle, while numerical readouts require the audience members to sit closer
to the finish line and at a more direct angle.

Note that some systems offer a remote readout, which can only be viewed by
officials. This method may not instill as much audience confidence, as the
results must be interpreted and announced by an official (Editors note: If
your track has a remote readout, always have two officials monitoring the

Nice to Have Options

Timer - A timer option is great to have. Even if the race is not scored
using elapsed time the timer can be used to show the advantage/disadvantage
of design techniques during workshops and to compare the results from
year-to-year. If selecting a timer option, make sure it is accurate to one
ten-thousandth of a second (0.0001). While .01 second is fine for
cross-country skiing, it simply won't do for pinewood derby racing.

Computer Interface - Computer interfaces are finding broad acceptance as
the best way to manage races. This option is not simply for the display
and automatic recording of race results, but for the seamless interface to
popular derby management software packages. Many customers report that
because of the ability to interface with race management software, their
group is asked to sponsor regional meets. Some have paid off their
investment by providing a race management service to organizations without a

Today, most finish lines use the PC's serial or parallel port. With the
wide-spread acceptance of USB (Universal Serial Bus), and the eventual
phase-out of the serial port, be watching for finish lines with a USB

Outdoor Use - Natural sunlight is rich in infrared light, causing
standard infrared sensors to trigger erratically. So, if your race will be
held outdoors, make sure the finish line is equipped with sensors designed
for use in sunlight.

Battery Power - A final possible option is battery operation. During a
pinewood derby, power, audio, and video cables are generally strung in all
directions. Eliminating the need to power the finish line means one less
cable to tape down, and one less power source to locate.


When it comes to judging pinewood derby races, clearly the electronic eye is
superior to the human eye. There are no ties, and no need for re-runs.
Everyone trusts this method of judging. Your pinewood derby will run
smoothly, finish on time, and leave everyone happy and looking forward to
next year. It just doesn't get any better than that!

From Pinewood Derby Times Volume 1, Issue 13

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