Starting Gate

Solenoid start gates make for consistent heat starts.
OneHour
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Starting Gate

Post by OneHour »

Need your recommendation for a starting gate to replace our manual starting gate. We have a laser starter that tends to be very unstable when the gates drop. The manual start does not produce very reliable and consistent start. Our pack is looking for something along the line of a solenoid starting gate. Any recommendation is much appreciated.

Thanks,

-L
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gpraceman
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Re: Starting Gate

Post by gpraceman »

While a solenoid may help, your gate should be consistent enough if you must operate it manually. Sounds like it is time to retrofit with a better start gate and then look at adding a solenoid.
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Re: Starting Gate

Post by SuperDave »

You seem to be confusing two issues: laser start detection and solenoid gate drop.

Laser start detection. In my opinion this is a needlessly expensive and trouble prone way to detect a start. A simple microswitch or magnetic sensor is far easier to implement. A magnet in the starting bar and a sensor nearby make for a simple system with the added benefit that it's insensitive to light, easily adjusted, stable and the wires don't move.

Solenoid gate drop. This is a neat idea if it's used to get the kids involved. Otherwise, it's just added complexity. I've posted elsewhere on this topic, but briefly, you need to be concerned not only with the mechanics and energy required to trigger the drop (like most of life, it's more complex than first imagined) but, more importantly, the flyback voltage generated by the solenoid when the power is removed.

You are correct in assuming that if you are doing timing, the gate drop an gate drop detection must be absolutely consistent, way more consistent than any human can be.
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Re: Starting Gate

Post by Go Bubba Go »

SuperDave wrote:You seem to be confusing two issues: laser start detection and solenoid gate drop.
I think the "confusion" may be that on occasion a laser start can be "tripped" by a harsh drop of the gate, before any of the cars actually cross the laser start detection beam. He seems to be thinking that a more consistent starting gate would eliminate "false/early" trips.

We had a couple of real "outliers" in our Pack race times this year. In one case we had 2 of my boys racing each other in sequence across a number of lanes. They maintained a pretty close space between them (faster car always 0.003 to 0.009 seconds ahead of slower), but their times were (for faster car) 2.203, 2.220, 2.206 and 2.256. In 2nd, 3rd and 4th heat his brother's car was consistently a few thousandths behind him, which would seem to rule out 2.256 as just a poor performance for the 1 car. Both cars (in fact all 4 cars in the heat) were approx. 0.05 slower for one heat only. (This unusually slow time actually drew the attention of the CubMaster, but after looking at me he just shrugged and continued on). I could understand the 2.220 due to "misc. variables", but the 2.256 seemed to fit mathematically only if the laser had tripped at start gate drop rather than when the first car crossed the laser gate (i.e the distance from the start gate to the trip takes about 0.05 sec.).

Not sure how to fix this problem for next year. Fortunately, it didn't occur often enough (or at the "wrong moment") this year so as to impact the results for this year's Pack participants. Except for in the Open Class, where it appears that my wife's car may actually have beaten mine if you remove her "bad" i.e. 0.05 added for early "trip" heat. Using average times, my car won if you include her "bad" heat. She did, in fact, beat my car "head to head" in a couple of races. However, since I had 4 "clean" heats and she had one "bad i.e. extra 0.05 sec heat", her average time took a 0.125 (approx.) hit that was more than my margin of victory when using average times.
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SuperDave

Re: Starting Gate

Post by SuperDave »

It's an interesting philosophical question. Should timing start when the first car crosses the line OR when the gate drops?

It seems to me that the former subtracts the reaction time of the fastest car in the current heat from the later which is equal for all heats, thus my preference is for the later.[/u]
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Re: Starting Gate

Post by Go Bubba Go »

SuperDave wrote:It's an interesting philosophical question. Should timing start when the first car crosses the line OR when the gate drops?

It seems to me that the former subtracts the reaction time of the fastest car in the current heat from the latter which is equal for all heats, thus my preference is for the latter.
I tend to agree.

Gotta give it some more thought about exactly what to change to, what it would cost to change, and how to "sell" the change. Everyone is "used to" the laser start and seems to think that it negates any starting gate consistency issues (I seem to be the only one that has noticed that the laser is subject to the occasional "early start" if the gate is opened too roughly).
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Re: Starting Gate

Post by gpraceman »

The start should be a consistent event. Having the cars break a beam as the start signal is not consistent due to the differing nose profiles of the cars running. The only way that I would use a laser or IR sensor for the start is if the pins broke the beam, not the cars. Often this is difficult to do with the manufacturer supplied brackets and commercial tracks. I much prefer a simple mechanical switch for the start. It will be more consistent and less problematic.

Then the second issue to look at is how consistent the start gate is at opening fast enough to pull the pins away from the cars without them starting to move. A good gate should not also jolt the track as it snaps open. If the jolting is the only issue, some adhesive backed padding may alleviate that problem.
Randy Lisano
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TAL
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Re: Starting Gate

Post by TAL »

I too would line the laser with the pins and not the cars...

I would make sure the gate is a smooth consistant drop pulled down by springs and locked up when holding the cars...

If you want to try a silonoid I would use the silonoid to pull the handle that drops the gate, that way the gate will still be consistantly pulled down by the springs alone... With this method if you have silonoid problems you can pull the pin on the silonoid and pull the handle manually without upsetting the remote starting switch and any timing mecanisims...

I have found a remote starting switch that starts the clock when the gate is dropped and releases the switch is about the most reliable method...
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Re: Starting Gate

Post by OneHour »

Go Bubba Go wrote: I think the "confusion" may be that on occasion a laser start can be "tripped" by a harsh drop of the gate, before any of the cars actually cross the laser start detection beam. He seems to be thinking that a more consistent starting gate would eliminate "false/early" trips.
Bubba is correct. I'm not confused between the two. The laser start frequently tripped early when the gates dropped and the cars have not crossed the laser starting beam. Yes, we would like to have a more consistent start.

Solenoid is a more elegant way to start than the handstart that we are doing right now where the starter has to hold the trigger and applies the same amount of pressure to the spring that is pulling on the gates. If the amount of pressure is not the same, the gates drop differently at a different rate for some reasons! We can tell that some heats the cars are being held up where as other heats they'd fly off the gates.

Everyone is correct. Laser is an expensive, unstable trigger. We just need a recommendation of a good reliable package that we could buy or build. Solenoid gate drop will be the added bonus.

Thanks for the replies so far.

- L
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Re: Starting Gate

Post by gpraceman »

OneHour wrote:We just need a recommendation of a good reliable package that we could buy or build. Solenoid gate drop will be the added bonus.
First, is your track a home built or a commercial track? If it is a Piantedosi Oars wood track with their old style start gate (rubber band holds it closed - wrist action opens it), you can get a new start gate from them and retrofit. Their new start gate snaps open, with the release of a lever.

After you resolve the start gate issue, then you still need some way for the timer to know when the race has started. You can use a simple mechanical or magnetic switch instead of the laser. Contact Micro Wizard about shipping you a mechanical switch, if they did not already provide one when you bought the timer.

Lastly, if you still want a solenoid operated gate, then you can build one with the plans at http://www.supertimer.com/pinewood/SolenoidStart.html (thanks SuperDave for making those plans available). I would recommend adding a normally open switch to bypass part Q1, so you can trigger the gate with a push button in addition to having a means to have the computer trigger it. New Directions also sells a solenoid start gate at http://www.newdirections.ws/startgate.htm, but I think it still requires you to use their Light Tree for the triggering of it.

SuperDave - Can the solenoid start gate that you have on the SuperTrack be used easily with other tracks? If so, do you sell these by themselves?
Randy Lisano
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Re: Starting Gate

Post by OneHour »

It's a 5 years old Best Track with its starting gate (I think?). The laser is from Micro Wizard and it has been replaced once when it burned out 2 years ago.

- L
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Re: Starting Gate

Post by gpraceman »

OneHour wrote:It's a 5 years old Best Track with its starting gate (I think?).
As far as I know, the Best Track start gate has always triggered with a lever and a spring would pop the gate open. You may need to add some extra foam padding to reduce the jolt from it opening.

If your track is that old, do you know if you have their old curve section? It was quite a tight curve. I believe they have a standing offer to replace any of the old curve section with a new one, at no cost.
OneHour wrote:The laser is from Micro Wizard and it has been replaced once when it burned out 2 years ago.
I would recommend that you contact them about getting a mechanical switch. You may need to get the switch mounting bracket from Best Track.
Randy Lisano
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Re: Starting Gate

Post by DerbyAddict »

gpraceman wrote: You may need to get the switch mounting bracket from Best Track.
Randy, what is this? I have never seen this on Steve's website. I would love to get a start switch bracket for our Best Track.
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Re: Starting Gate

Post by gpraceman »

DerbyAddict wrote:Randy, what is this? I have never seen this on Steve's website. I would love to get a start switch bracket for our Best Track.
It is something they provide if you indicate on your order that you will be using a Fast Track timer. If I recall right, it would be a piece of L bracket with a phone jack connected to the start switch Then you just need a regular phone cable to connect it to the timer.
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Re: Starting Gate

Post by PWD »

This sounds awsome. I have never heard of them providing such a bracket. We basically made our own out of wood. It has worked pretty well. But Like to get something a little more professional.
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