Electronic FinishLines for outdoor use

Commercial timing systems
User avatar
Stan Pope
Pine Head Legend
Pine Head Legend
Posts: 6856
Joined: Sat Jul 05, 2003 7:01 pm
Location: Morton, Illinois
Contact:

Re: Electronic FinishLines for outdoor use

Post by Stan Pope »

As for suggestions ... you might pass along a suggestion that they use three judges (one electronic and two human) and go with majority rule. Of course, they each call their result before consultation with each other or with the electronics. I like the "point to the winning lane" approach for each judge. Then sort out conflicts. Usually, you don't even have to look at the electronics.

If the judges have reasonable vision lines, calling 1/16" differences accurately is a reasonable expectation.

The last part of the problem is to tell the electronic scorekeeper that the electronic finish line is wrong and that the correct result should be ...!
Stan
"If it's not for the boys, it's for the birds!"
RMoose
Master Pine Head
Master Pine Head
Posts: 125
Joined: Sat Apr 17, 2004 9:30 pm
Location: North Carolina

Re: Electronic FinishLines for outdoor use

Post by RMoose »

Stan,

Thanks for the suggestion on finish line judges! I do think that one is not enough, especially after watching the result. I will pass your suggestions along to the appropriate people and hope for the best for next year's race!
We are Ambassadors for Christ
User avatar
terryep
Merchant
Merchant
Posts: 423
Joined: Sat Aug 09, 2003 8:13 pm
Location: Fredericton, Canada
Contact:

Re: Electronic FinishLines for outdoor use

Post by terryep »

Stan Pope wrote:As for suggestions ... you might pass along a suggestion that they use three judges (one electronic and two human) and go with majority rule. Of course, they each call their result before consultation with each other or with the electronics. I like the "point to the winning lane" approach for each judge. Then sort out conflicts. Usually, you don't even have to look at the electronics.

If the judges have reasonable vision lines, calling 1/16" differences accurately is a reasonable expectation.

The last part of the problem is to tell the electronic scorekeeper that the electronic finish line is wrong and that the correct result should be ...!
After watching the races Saturday I agree that human judges can determine 95% to 100% of the races accurately but you'll never really know if it's skill or confidence. We had 2 tracks running, one with an electronic finish line and one without. Only one re-race on the all human track. One advantage of the electronic fish line is that the audience gets to see who won. Often site lines are poor with cubs and judges hovering over the line. The part I worry most about is that one mistake can and does alter the finish order.

Terry
User avatar
Stan Pope
Pine Head Legend
Pine Head Legend
Posts: 6856
Joined: Sat Jul 05, 2003 7:01 pm
Location: Morton, Illinois
Contact:

Re: Electronic FinishLines for outdoor use

Post by Stan Pope »

The advantage of combining human and electronic judges is that the electronics judge will teach the human judges and the human judges will correct the obvious errors by the electronic judge.

I hate it when folks allow an obviously wrong electronic judge decision to stand or compound their failure by rerunning the heat. ("You mean I've got to win this heat again?")
Stan
"If it's not for the boys, it's for the birds!"
dguy
Apprentice
Apprentice
Posts: 5
Joined: Mon Feb 16, 2004 8:39 pm

Re: Electronic FinishLines for outdoor use

Post by dguy »

Hello,

I have just rebuilt my timer from last year, and the sensors worked fine inside & outside.

The main trick that I reccomend is to use the quad comparitor circuit like Pack 471's curcuit, or like in my schematic posted last year. But be sure to replace R9/10 & R11/12 with a 20 turn precision potentiometer the absolute value is not critical, I used 20 K but lower ohmic value is fine. The wiper of the trim pot becomes the reference voltage for the comparitor, the single reference voltage can be used for all comparitiors.

Then I adjust the trim pot so that the lane is just barely on with the full LED illumination. THis way almost any deviance down in intensity on the sensor will trip the circuit. Also, the trim pot can be readjusted depending on where you set the track up.

David Guy
User avatar
terryep
Merchant
Merchant
Posts: 423
Joined: Sat Aug 09, 2003 8:13 pm
Location: Fredericton, Canada
Contact:

Re: Electronic FinishLines for outdoor use

Post by terryep »

What happens if a cloud passes by? Or a spectator casts a shadow? Won't this trigger one of the lanes?
Terry
dguy
Apprentice
Apprentice
Posts: 5
Joined: Mon Feb 16, 2004 8:39 pm

Re: Electronic FinishLines for outdoor use

Post by dguy »

Terry,

I sorry if I wasn't clear. I set the treashold so that with no addtional light it just bairly holds the photo transistor on. Thus any addtional light will keep it on a little more.

My main point was to use a variable voltgae divider instead of fixed resistors. That way each track can be optimized and adjusted to accmodate the particular physical & electronic differences nessisary to acheive the optimum results.

Dave
User avatar
terryep
Merchant
Merchant
Posts: 423
Joined: Sat Aug 09, 2003 8:13 pm
Location: Fredericton, Canada
Contact:

Re: Electronic FinishLines for outdoor use

Post by terryep »

If you are following this thread you may also want to check out this related thread http://derbytalk.com/viewtopic.php?t=1102
Terry
John Shreffler
Merchant
Merchant
Posts: 163
Joined: Wed Feb 04, 2004 8:32 pm
Location: Vienna, VA
Contact:

Re: Electronic FinishLines for outdoor use

Post by John Shreffler »

Optional outdoor sensors for The Judge have been reduced in price to $29 plus $5 per lane. They work in full sunlight, although a little shade helps immensely in seeing the red indicator lights.

On the subject of painting black lines at the finish line: Don't assume that black paint looks dark in infrared light. Some do, some don't. It is instructive to remove the infrared filter from your CCD (you will have to stop way down to compensate) and see how the world looks. You will see things that appear bright to the eyes now look dark, and vice versa.
Black flock paint is reliably dark in IR light. But aside from that, the paint band is not really very helpful in IR pollution situations.
Post Reply