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getting chrono consistancy

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Re: getting chrono consistancy

Postby petew » Sun Oct 26, 2008 8:56 pm

The light has to be above the difusers. The chrono uses the light shining down to make a shadow from the arrow as it passes over the sensors.
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Re: getting chrono consistancy

Postby tjdeerslayer37 » Sun Oct 26, 2008 8:59 pm

i called the company and they said my 75 watt halogen bulb in my workilght was likely not bright enough. they tell people to use those big halogen spotlight/worklights that have something like 400 watt bulbs! lol. he said a 150 should work fine shining up at the white top (i explained how i had it set up) i havent had a chance to try it out with a bigger bulb yet though.
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Re: getting chrono consistancy

Postby Kirkll » Sun Oct 26, 2008 11:08 pm

does it make a difference using it in sunlight vs artificial light TJ ? i know the guys in the archery shop had theirs weird out under floresent light at night, but worked fine during the day... hows that for strange :roll:
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Re: getting chrono consistancy

Postby tjdeerslayer37 » Mon Oct 27, 2008 5:54 am

he said sunlight works good too. im pretty sure they dont like flourescents.
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Re: getting chrono consistancy

Postby petew » Mon Oct 27, 2008 7:02 pm

"copied from the manual" see reflections and lighting problems.


How It Works
The ProChrono Digital chronograph operates on the principle of measuring the time it
takes for an object to travel from the first projectile sensor to the second projectile
sensor. The sensors, mounted internally in the case, gather light through the two
rectangular openings in the top of the case.
The sensors are actually specially designed electromechanical devices that can detect
changes in light intensity that occur when a projectile interrupts light rays shining into
a sensor when it passes over the opening above.
If you can imagine looking up at the sky through a tube, you will gain an
understanding of what the sensors see. The only light they see is what is directly
above them. Any light blockage caused by an object passing over them is converted to
a signal that is detected by the ProChrono Digital. The chronograph measures the
elapsed time between the light interruptions a projectile makes as it travels over the
front, and then the rear sensor. It then converts this time into velocity and displays it
on it’s front-mounted LCD screen so that you can read it.
Before You Start, (Or if You Encounter
Problems) Consider The Following:
Lighting Conditions
As mentioned above, the ProChrono Digital chronograph is a light-sensing device. In
the course of use, the chronograph must cope with a multitude of different lighting
conditions…sunny clear skies, overcast days, low light situations, reflections,
different colors and shapes of projectiles, etc. Although the ProChrono Digital works
flawlessly over a very wide range of lighting conditions, there are times when the
lighting environment can affect chronograph performance.
Diffuser Use
It may be counterintuitive, but the best natural conditions for using the ProChrono
Digital chronograph do not occur on a clear, sunny day, but rather on overcast, cloudy
days. This is because the ProChrono Digital needs a diffused light source to work
properly.
You can understand what diffused light is by considering two light bulbs. One light
bulb has a clear glass envelope, and one is frosted. The clear light bulb appears to be
brighter when you look at it, but it is also glaring and gives off uneven light coverage
and causes shadows, so it is not as good for lighting use in most situations. The
frosted bulb appears to our eyes as a round glowing orb of homogenous light. The
frosted coating causes the light to disperse and scatter so that it illuminates in a more
even way, providing better coverage and less shadows. (Note: This is not to say that a
frosted incandescent bulb, by itself, is a good light source when you use your
chronograph indoors. It is not.)
On bright sunny days, you should always use the milky plastic diffuser screens so that
the light that the chronograph sensors see from above is homogenous and scattered.
This will greatly reduce errors in velocities and missed detection.
On the other hand, on an overcast day, it is generally better to remove the diffusers.
This is because the clouds act as diffusers and so no further diffusion is needed; rather
in this case it is more advantageous to allow more light into the chronograph by
removing the diffusers entirely.
Some Common Conditions that May Cause Problems
You can encounter a wide variety of lighting conditions if you use your chronograph
outside. The following are some things to look out for:
Reflections
On sunny days shiny, light colored or smooth projectiles may cause reflections which
can induce velocity errors. Be sure to use your diffusers on sunny days. However, this
may not be enough, by itself, to correct the problem.
You can move your chronograph to a location in the field of a shadow cast by a
building or an opaque wall. Make sure the sensors have a clear view of the sky but the
chronograph itself is within the shadow. This will eliminate reflections from direct
sunlight, while still assuring that the chronograph has a direct view of the sky.
If you are having problems with reflections from shiny bullets or arrows, another
remedy you can try is to take a black marker and color your projectiles with it. This
will greatly reduce glare and may be needed if you have to use the chronograph in less
than ideal lighting conditions.
Under extreme conditions it may be necessary to create and use shields on the sides
and/or the top of the chronograph shooting area rods and diffusers. Be sure to use
cardboard or something similar that will not cause any problems with ricochets, etc.
Trees
Trees do not provide a suitable shadow and in fact you should not locate your
chronograph in the shadow of a tree as it is likely to cause more problems than it
could ever solve.
Sunrise and Sunset
The lighting conditions at sunrise and sunset can cause errors due to reflections
because of the extremely low angle of the sun, or the low light levels encountered.
Electrical Interference
It is unlikely but possible that use of the chronograph in close proximity to a radio
tower, microwave tower, or large power facility could cause errors and functional
problems. Avoid use in these areas if you encounter these problems.
Using the Chronograph Indoors
Common problems that occur indoors include the following:
· Not Enough Light
Indoor lighting is often not bright enough for use with the chronograph indoors.
· Wrong Kind of Light
As mentioned above, bare incandescent lamps are not suitable as a light source for the
ProChrono Digital, mainly because they are not usually diffuse and scattered enough.
Florescent lamps are not at all suitable, because although we cannot see it with our
naked eye, they actually vary in intensity many times a second and the ProChrono
Digital can detect this, which confuses it and renders it useless as long as it’s sensors
fall under the influence of the florescent light.
Competition Electronics offers a specially designed indoor lighting kit that was
created for indoor use with the chronograph. More information on the indoor kit is
found in the “accessories” section of this manual.
Lighting and Accuracy
Adverse lighting conditions can cause accuracy issues, and having read the above, you
should be able to understand why. Any change in light intensity that a sensor detects
other than the actual passing over the sensor of the leading edge of the projectile will
give errors.
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Re: getting chrono consistancy

Postby Kirkll » Tue Oct 28, 2008 10:24 am

Nice going Pete! ...."can't tough that" :D :D
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