Change in run times using a laser start

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DerbyDash
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Change in run times using a laser start

Post by DerbyDash » Wed Mar 06, 2013 1:39 pm

In reading on DT about tracks that use the laser start set up right after the starting line, it seems that most do not like it.

In looking at the times for our PWD this year, it seems that after the laser was touched to reset it, the times for the next races were different than those that ran before - sometimes faster / sometimes slower. In analyzing this by looking at the people who ran right before and then right after the resets, it seems that there was a change in the times. This would seem to make the results inaccurate when we were using overall time to determine a winner.

Do you agree that the adjustment of the laser would have an effect on the overall times for the racers? I believe it does. Any thoughts on how much it could change? More than a few hundredths? None at all?



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birddog
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Re: Change in run times using a laser start

Post by birddog » Wed Mar 06, 2013 4:41 pm

If at all possible, move to a timer that activates by a mechanical switch.

The problems with the laser start systems is that they can trigger early, sometimes just by bumping the track. I've seen races that involved times that were off by 1.5 seconds (i.e. cars that would normally finish in about 3 seconds, were recorded at 4.5 seconds). the good news is that those heats are "easy" to see something went wrong. I've also seen heats where the times were off by 0.2 seconds. those mistakes are harder to detect with the naked eye and most times go undetected, causing problems with race results.

GPRM 12.x has a new feature to help dectect these types of problems, but my advice would be to throw out the laser and move to a mechanical switch.

birddog



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gpraceman
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Re: Change in run times using a laser start

Post by gpraceman » Wed Mar 06, 2013 5:17 pm

Timing starts when the beam breaks. Usually, that is when the first car hits the beam. Depending on the nose profiles of the cars in a heat and which gets the faster jump off the start, that can add significant timing variation to all cars in that heat. Part of the start gate should be breaking the beam, like the pegs, to alleviate those issues.

Better yet, use the mechanical switch. ;)


Randy Lisano
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Awana Grand Prix and Pinewood Derby racing - Where a child, an adult and a small block of wood combine for a lot of fun and memories.

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sporty
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Re: Change in run times using a laser start

Post by sporty » Wed Mar 06, 2013 5:34 pm

One of the packs, my sons use to attend. The laser was mounted on plate, and a magnet, that stuck to a plate that was screwed into the wood of the track. The problem was, that the solenoid start gate or prior to using the old rubber band method.

That the quick release, jump. would cause the laser to move a tad. So they ended up mounting it right to the track, versus the magnet.

This was kind of the kit option at one point, thats what you got as a mounting kit and naturally it has its flaws.

Sporty



DerbyDash
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Re: Change in run times using a laser start

Post by DerbyDash » Thu Mar 07, 2013 8:50 am

Can anyone give an overall cost estimate (rough number) to change to a mechanical switch?



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gpraceman
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Re: Change in run times using a laser start

Post by gpraceman » Thu Mar 07, 2013 9:54 am

DerbyDash wrote:Can anyone give an overall cost estimate (rough number) to change to a mechanical switch?
Check your equipment box. You might already have the switch, as Micro Wizard sends that even if the laser start system is ordered. Otherwise, you can contact Micro Wizard regarding cost to get the switch and mounting bracket (if you have a Best Track or Micro Wizard track).


Randy Lisano
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Awana Grand Prix and Pinewood Derby racing - Where a child, an adult and a small block of wood combine for a lot of fun and memories.

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