# Laptimer 2000 problems



## Boosted-Z71 (Nov 26, 2007)

Hello All, I have a Laptimer 2000 setup with infra red / photo cells, a relay start setup. This is with a dedicated monitor, & CPU shared between 2 different setups of photo cells & IR lamps on 2 different tracks. A 4 lane road course, good sized layout (74 running feet), & a 4 lane routed 4 x 8 oval 

I don't run both tracks at the same time, I just switch the cord from the computer to the correct track photo cell box on which track I am running to time laps. The timing system works on both tracks.

My only problem is with false signals on the oval, it is a 4 x 8 and we run T-jet Fray style cars, some in the very low 2 sec / lap range. Most magnet cars, & fast inlines can run in the low 1 sec / lap. 

We only notice the false lap times with some T-jets, not all though, and its not just my cars, others have raced their cars on similar timing setups with no problems. The false signals seem to occur when you pump the throttle in the curve away from the timing bridge, (There is no chance of shadows or any physical interference, as it is away from the drivers) It seems to happen when you let all the way off & then all throttle into the straightaway, Controller choice does not seem to matter, I have tried everything from common AFX, to Parma, to Professor Motor electronic style. I have also seen T-jet cars that you can free rev on the track, & the timing circuit will register times in other lanes when no one else is on the track, although this is very random. 

I have been over & over the wiring, I have seen no problems on the road course, it never misses a lap, unless someone crashes under the timing bridge.

Both tracks are on the same power supply, A very clean 0-15amp, 0-24 v Hewlet Packard Laboratory style power supply, very clean with hardly any AC ripple.

Like I said I have been over the wiring, many times, I have installed large capacitors on each of the 4 lanes at the drivers stations. I am at my wits end with this setup on the oval. It works great on the road course, with all cars, and we have not seen any problems on the oval with the inline armature cars or AFX Magna-traction style cars. We have ran some inlines that pull 3-4 amps each & still no problems or missed counted laps

Any thoughts or suggestions on what I could try would be greatly appreciated, I have dug around on here but found nothing yet that has helped. I did read in one post that the wiring diagram on Greg Brauns website for adding the starting relay was incorrect, I know I have the same relay he suggests hooked up as per his diagram, and it does work, so if anyone can explain the correct way I would appreciate that as well. 

Thanks

Boosted-Z71


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## SwamperGene (Dec 1, 2003)

It's most likely EMI/RFI interference. Try powering up the timing setup on the oval but running some known offenders on the roadd course, chances are they will still trigger false laps on the oval.


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## Boosted-Z71 (Nov 26, 2007)

Thanks I will give that a try & report back, if so do you have any thoughts on how I can fix this?

Boosted


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## alpink (Aug 22, 2010)

small capacitors placed within each t-jet has been known to quell the interference. I do not know the value.


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## usdra (Jan 23, 2007)

solder some of these across the rails in each lane near the sensors. It will clean up the noise. Al's suggestion also works. http://cgi.ebay.com/25pk-1-2PF-50V-...541?pt=LH_DefaultDomain_0&hash=item5ad6329fad

Eric
www.mobydiditperformance.com


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## Boosted-Z71 (Nov 26, 2007)

Thanks, I will pick up some of the capacitors & give them a try.

Appreciate the help 

Boosted


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## Boosted-Z71 (Nov 26, 2007)

I did a little testing & here is what I found, I only get the ghost laps / interference on the scoring system on the course that I am running on at the time, dont get interference from running on the oval to the road course or vice versa. I bought the capacitors but I have not added them to the track yet, that is next on the list. Should I add them at closest power tap prior to the scoring system in the direction of travel, or do they need to be added right before the scoring setup? Thanks, just want to get some ideas as this is not going to be an easy fix if I need them right before the scoring setup

Boosted


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## mikeponiatowski (Jan 24, 2006)

usdra said:


> solder some of these across the rails in each lane near the sensors. It will clean up the noise. Al's suggestion also works. http://cgi.ebay.com/25pk-1-2PF-50V-...541?pt=LH_DefaultDomain_0&hash=item5ad6329fad
> 
> Eric
> www.mobydiditperformance.com


This is a solution I noticed in the Trackmate Installation Manual. I have the same problem and will give this a try.


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## bemoore (Dec 23, 2008)

I also suggest making "twisted pairs" of all your wiring. Twisting a pair of wires will reduce its susceptibility to EMI. Twist the wires going to each rail of a single lane, ideally back to your power supply or terminal block. Twist the wires from your timing circuit too. Without knowing the design of your timing circuit, I can't tell you exactly how to twist them, but you want to be able to twist together a pair so that any EMI "spike" will cancel out. Any circuit has to have a supply path, and a return path. If you can twist together the supply and return path for each circuit, most EMI "spikes" will get canceled out. Twist the supply and return paths of each circuit. If you have daisy-chained ground, you may have to re-wire the circuit. A ground wire (return path) that is used by multiple circuits can be a source of interference. Run separate supply and return paths as far as you can back to the computer, power supply, or whatever.

Edit to add:
Re: Capacitors... The "large capacitors" you used on each lane are not good for suppressing EMI. They're good for smoothing out power supply ripple. You need smaller (0.01uF or so ceramic) caps for EMI problems.


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## Boosted-Z71 (Nov 26, 2007)

Thanks Bemoore, I do have all the sensor wires run as twisted pairs but on the oval especially they are close to the power wires & I am sure the power wires on the oval are not twisted. This gives some ideas of things to look at, hope to get the caps installed in the next couple of days and maybe get some wires twisted as well

Boosted


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## bemoore (Dec 23, 2008)

Boosted-Z71 said:


> Thanks Bemoore, I do have all the sensor wires run as twisted pairs but on the oval especially they are close to the power wires & I am sure the power wires on the oval are not twisted. This gives some ideas of things to look at, hope to get the caps installed in the next couple of days and maybe get some wires twisted as well
> 
> Boosted


I'm a bit surprised. I'd had thought that twisting the sensor wires would have been enough. Given that, I'd twist the power supply wires, and separate the sensor wires from any wire carrying current to a lane. Oh, and add the caps, too.


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## Boosted-Z71 (Nov 26, 2007)

Gentlemen, Thanks a million for the suggestions, this problem has been driving me crazy for almost a year. I use binding posts for my controller station connections, so I quickly added the caps at the binding posts just as a quick check, then fired up my worst offender of a T-jet car. Guess what almost no false laps, I ran 50+ laps on each lane, with maybe 2 false laps max. 

In the building of this I thought I had taken all the care that I could in wiring this track, twisted pairs, no shared, chained grounds, separate power for the timer etc etc, and it drove me crazy, as I like to run t-jets & want a true count of how fast & the laps I go. 

In short anyone who is having false lap counts with especially with t-jets, needs to add the caps & go from there. I think the caps will solve your problems.

Thanks to all who replied, I hope this info may also help others with similar lap timer problems, I know during my search I ran into several people along the way that had similar lap timer problems, but no answers.

Thanks again 

Boosted


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## usdra (Jan 23, 2007)

Boosted-Z71 said:


> I did a little testing & here is what I found, I only get the ghost laps / interference on the scoring system on the course that I am running on at the time, dont get interference from running on the oval to the road course or vice versa. I bought the capacitors but I have not added them to the track yet, that is next on the list. Should I add them at closest power tap prior to the scoring system in the direction of travel, or do they need to be added right before the scoring setup? Thanks, just want to get some ideas as this is not going to be an easy fix if I need them right before the scoring setup
> 
> Boosted


I have had the best luck near the sensors but some may need to be added at the power taps

Eric


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## tonesua (Jul 1, 2006)

*can someone confirm this:*

So, is it not a good idea to set up the IR sensors near any power taps? 
Secondly, does anyone have any pics of the capacitors set up and soldered in your set up?

thanks.


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