Just need to vent...

General race coordinator discussions.
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bad_karma_2805a1
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Just need to vent...

Post by bad_karma_2805a1 » Wed Mar 17, 2010 2:14 pm

So we had our Pack's derby last weekend. It is funny how people will tell you how great it turned out, when you know what a disaster it was. From no PA system to a bunch of late entries...it seemed like a train wreck to me. Once the races got going things seemed to smooth out and we all got in the zone. We were dropping cars down the track on an average of every minute. So at the end we handed out the awards and I was thinking...this one is done and in the books.

WRONG! It seems that one of our more committed fathers found a flaw in the results. Turns out that the first heat had a timing error. We can't figure out how, but all the cars ran over a second slower then normal. So just when I was feeling good, the debate starts...his stop watch doesn't match the results of the race, his son should have gotten at least 3rd, the results are totally messed up...we needed to address this.

I have spent the last few days going through all the race data. I took all the cars and removed the slowest time, then I recalculated the results. Guess what...his son now comes in at first place for his rank and second for the Pack. Now there is no way God's green Earth I am taking a trophy back. So we have decided that we have two ties. I am not thrilled with this decision but I think it is fair for everyone.

I can tell you one thing though...I will be making a few changes to our set up for the District Race we are hosting next month. Not sure I can deal with another case like that.



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Re: Just need to vent...

Post by psycaz » Wed Mar 17, 2010 5:00 pm

Way to handle it with the NOT taking a trophy away. Just purchase another and reward the other scout. Mistakes happen, what matters is how the corrections are handled. On this one, you deserve a :clap:



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Re: Just need to vent...

Post by Kenny » Thu Mar 18, 2010 7:05 am

What a bummer. It seems that we've had our share of challenges, especially when we implement new things like networking the check-in pc and awards printing pc with the official race pc, etc. There's always something! How your group reacts and responds says a lot about your organization.

It sounds like you're handling things in an appropriate way. You're not embarassing anyone and you're recognizing the true winners.

Everyone involved are volunteers, afterall, and the "customers" must realize that we are quite imperfect...stuff happens.

That said, I'd be sure to have lots of "dry run" practice before districts!

K



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Re: Just need to vent...

Post by gpraceman » Thu Mar 18, 2010 11:21 am

After a discussion with bad_karma_2805a1, it seems to be a laser sensor alignment issue. The abnormally long time was likely due to the beam misaligning from vibration of the gate opening or maybe the start gate operator accidentally broke the beam or bumped the track. In either of those scenarios, the times would be longer than if the cars broke the beam to start timing.

The lasers are cool and all, but there really needs to be a better way to mount the two parts of that unit to the track. I saw one pack use a 1x2 and attached the two units to that, then the 1x2 to the track. They were able to maintain the alignment easier. Still, if the alignment issue is addressed, there will be timing variability unless it is the gate that is causing the beam to break, not the first car to reach the beam. With some tracks, it is not easy to mount the laser sensor so the pins break the beam. Some cars get a faster jump off the start and cars have differing nose profiles, so there is not a consistent start event for the timer to go by. That results in timing variability. That is not an issue if scoring by points, but it sure can be if scoring by times.

Personally, I prefer using a mechanical switch to let the timer know the race has started. Timing will be based on the same event every heat (gate opening) instead of the first car to get to the beam. If using GPRM and a Fast Track timer, it has an added advantage that if you have a car not finish, instead of pressing the Escape key to get GPRM to tell the timer that the race is over, just raise the gate. Closing that switch tells the timer that the race is over and it sends the results for the cars that finished. With some timers, like Fast Track, you don't want the start gate operator to close the gate while you still have cars running down the track.


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Re: Just need to vent...

Post by rpcarpe » Thu Mar 18, 2010 11:27 am

We used GPRM last weekend at District.
Worked fine after I figured out the 'don't close the gate' rule.
The pre-testing included fast Dad cars that gave us a good idea what a good car should run.
Anything too far from that we re-ran.
Also, excessive floor vibration (100 Cubs pounding the stage during the last heat) made the times FASTER by about 1 full second. Re-run the heat.


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Re: Just need to vent...

Post by gpraceman » Thu Mar 18, 2010 11:34 am

rpcarpe wrote:Also, excessive floor vibration (100 Cubs pounding the stage during the last heat) made the times FASTER by about 1 full second. Re-run the heat.
I don't see how that could cause faster times. :scratching:


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Re: Just need to vent...

Post by rpcarpe » Thu Mar 18, 2010 11:59 am

I'm not track owner/expert. But it did. Any race with a lot of pounding on the stage, the times went short. Optical sensors at the finish line, mechanical at the start.
I don't think I closed gate early... it wasn't a huge worry. We just re-ran it, no one argued about it.


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Re: Just need to vent...

Post by gpraceman » Thu Mar 18, 2010 12:41 pm

rpcarpe wrote:I'm not track owner/expert. But it did. Any race with a lot of pounding on the stage, the times went short. Optical sensors at the finish line, mechanical at the start.
I don't think I closed gate early... it wasn't a huge worry. We just re-ran it, no one argued about it.
Hmm... There are a couple of possible scenarios for abnormally short times that I can think of. A sticky start switch or a power issue.

If you had a sticky start switch, I would think you would have seen more than one heat have a problem.

If power somehow got interrupted as cars were running, then when the timer powers back up, it would see that the start switch was already open and start timing. All it would take is a momentary loss of power (blink of an eye). I have actually seen this happen at a race I ran last year. I believe that particular case was due to the timer being plugged into the same outlet as a lead melting pot. I think that when the pot's thermostat kicked in to maintain temp, this caused a brief power fluctuation. The timer display would blink briefly and times would be abnormally low. Looking at the raw data that the timer sent (GPRM records this info to the HardwareDebug.log file) I could see that the timer was sending its copyright statement whenever abnormally low times would occur. That only happens when that timer is powered up. So, in your case, maybe all that cub induced vibration was enough to jostle the power connection to the timer (at the timer or at the outlet) enough to cause a momentary loss of power.


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Re: Just need to vent...

Post by FatSebastian » Thu Mar 18, 2010 12:58 pm

gpraceman wrote:There are a couple of possible scenarios for abnormally short times that I can think of. A sticky start switch or a power issue. [...]
Impressive analysis! :thumbup:



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Re: Just need to vent...

Post by Mr. Slick » Thu Mar 18, 2010 9:10 pm

Bouncing floor by the finish line can make it sway/vibrate enough to cause the early finish too. We have one site with a floor that bounces lots and we have to remind the boys not to jump up and down by the finish line. We have them move towards the start gate if they want to jump up and down. :D


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Re: Just need to vent...

Post by gpraceman » Thu Mar 18, 2010 9:29 pm

Mr. Slick wrote:Bouncing floor by the finish line can make it sway/vibrate enough to cause the early finish too. We have one site with a floor that bounces lots and we have to remind the boys not to jump up and down by the finish line. We have them move towards the start gate if they want to jump up and down. :D
If that were the case, I would think that you would see more of an arbitrary finish order. Whereas if the finish order looks to be correct (not sure if that was the case or not at rpcarpe's race) but the times are abnormally short, then I would look at the start switch or a power issue.

BTW, the case that I stated about the lead melting pot with last year's race, I came to that conclusion this year. I had never seen timer behavior before or since at the multitude of races that I have run with that timer. It was at this year's race at that same church that someone at the pit table commented about the lead pot. That was my Ah Ha! moment. The setup for both races was the same, so that was the same outlet used by the timer and lead pot at last year's race. We made sure the pot was turned off before racing started and didn't see that problem at all this year.


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Re: Just need to vent...

Post by Kenny » Fri Mar 19, 2010 7:07 am

Just thinking about this I wonder if there also could have been a data communication error. Similar to having a poor serial connection, com port contention, improper parity bit setting, or even just a intermittent UART-like component failure. Bad or noisy communications or physical data communication cable connection can sure cause some weird and seemingly random results.

K



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Re: Just need to vent...

Post by gpraceman » Fri Mar 19, 2010 7:30 am

Kenny wrote:Just thinking about this I wonder if there also could have been a data communication error. Similar to having a poor serial connection, com port contention, improper parity bit setting, or even just a intermittent UART-like component failure. Bad or noisy communications or physical data communication cable connection can sure cause some weird and seemingly random results.
I haven't seen a case of that with any of my software customers in 10 years of being in business. I have seen cases where there is an issue with a USB to Serial Adapter where it sends garbage characters, but there is no confusing that with real timing data. If there was a problem with any of the COM port settings in the UART, then you'd lose the connection to the computer altogether.


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Re: Just need to vent...

Post by Kenny » Fri Mar 19, 2010 7:54 am

It seems to me a noisy data stream is just as likely to cause erroneous results, if not more so, than intermittent power loss in the middle of a heat.

Picture this:
Three wire data connectons on degraded 50-100 foot long cat 3 or worse telephone wire, taped together with ungrounded two-wire 50 foot power cords, switch wires that act as antennas in a room with 50 cell phones, and 4 wireless microphones, 50 flourescent lights 2 with faulty ballasts, creates a potentially challenging environment. We've solved our own problems on race day related to such things and saw no need to call GPRM.


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Re: Just need to vent...

Post by gpraceman » Fri Mar 19, 2010 8:32 am

Kenny wrote:It seems to me a noisy data stream is just as likely to cause erroneous results, if not more so, than intermittent power loss in the middle of a heat.

Picture this:
Three wire data connectons on degraded 50-100 foot long cat 3 or worse telephone wire, taped together with ungrounded two-wire 50 foot power cords, switch wires that act as antennas in a room with 50 cell phones, and 4 wireless microphones, 50 flourescent lights 2 with faulty ballasts, creates a potentially challenging environment. We've solved our own problems on race day related to such things and saw no need to call GPRM.
Not saying that it isn't possible. I would think if the data stream is being corrupted that erroneous characters would be included, not strictly numerical characters for the lane numbers or times. I just haven't seen any cases of erroneous characters sporadically showing up in a customer's HardwareDebug.log file for GPRM. If you can produce results like that, I'd certainly be interested to see it.

Also, erroneous characters would cause problems with the software parsing the results. GPRM filters out anything non-numerical. For example, if the data looked like "1=3.2@45 2=3.1456 3=3.8465 4=3.6745" then the first lane's time would be filtered out altogether and no results posted for any lanes (it would sit and wait for the timer to send the first lane's time). If the software was not posting times periodically, then I'd be hearing from the customer and I'd examine their log file.

A power loss in the middle of a heat is pretty easy to spot. Most timers send a copyright statement or other data when first powered up. If that data is sent between the software resetting the timer and the results being sent, then it is a no brainer on the power interruption. GPRM's log file is extremely handy for seeing such a scenario.

I have seen garbled communications before, but it is very blatant (pretty unintelligible) and the software is not able to parse the data. These cases have been pretty rare in my experience.


Randy Lisano
Romans 5:8

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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