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Discussion Starter · #1 ·
I'm hoping to dip a toe in the waters of electronic lap timing by setting up Laptimer 2000.

I'd be grateful for any advice from existing users; particularly regarding how you connected sensors to your computer.

I'm hoping to use split tape 'dead strip', and parallel port of an aged laptop running WindowsXP.

David.
 

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*** Leo A Capaldi ***
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I have been using Laptimer 2000 for several years - on two layouts. I use optical sensors (photo-diodes) connected as per the Laptimer diagrams (Trackmate compatability). For home two-lane racing this works great. However, there is a fundamental flaw in that the timing stops when the winner crosses the line. That means no real time for second, third, etc.

I have connection to the PC parallel/printer port. I would expect that a dead/isolated strip would work ok. Any decent computer will have short-circuit protection built in, if you want to be safe, fit 100 ohm resistors in series with the isolated strip.

Some computers only have output on the parallel port and some need to have input enabled via the motherboard set-up.

Have to say that if this is all gobble-de-**** to you then you're not likely to get this working.

Have you tried running Laptimer yet or are you not even at that stage yet?

Kind regards, Leo
 

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Discussion Starter · #3 ·
Leo,

Thanks so much for your helpful reply.

I'm just on the right side of the cluelessness that you have detected from my question (but only just!).


With a combination of your advice, and Brent Carlson's page on 'how to test your parallel port to see if it will run Laptimer2000',which my son has just sent me, I'm now optimistic I will get this thing working .

Brent makes it very clear which holes NOT to stick wires in - and it was uncertainties on this issue which were holding me back.

Regards,

David.
 

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Discussion Starter · #4 ·
Hooray! Hooray!

Got Laptimer2000 working on my ancient IBM Thinkpad.

Well, after hours of frustrating fiddling with settings, and getting nowhere,discovered that pin25 on parallel port not working.

Stuck the wire in pin23 - worked perfectly in 1, 2 , 3 and 4-lane configuration.

When I say worked, it worked by the Brent Carlson method of testing by poking wire in the holes.

All that remains is to cut the tapes and wire it up.

Thanks to all who offered advice.

David.
 

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*** Leo A Capaldi ***
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Well done,
Getting it working can be frustrating, you just have to persevere.

Leo
 

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Discussion Starter · #6 ·
Thanks, Leo.

Bit of a false dawn, i'm afraid.

Made 3inch split section of tape in each lane, connected it all up.

Worked perfectly for about 5 minutes then lanes two and three (pins 10 and 11) stopped working.

Checked all connections. Turns out pins 10 and 11 not working. Don't know why. Computer says parallel port is working correctly, but it obviously isn't.

Answer may be to buy Track mate and a new computer - when blood pressure settles to less dangerous levels!

David.
 

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Rich Dumas
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Trackmate connects to a serial port, so you could probably use the same computer. I am not certain if parallel ports like having a dead short across them. Since you still have one lane working you might try putting a 470 ohm resistor in series and see if it still counts.
 

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Guess it's a bit late now, but normally you would protect the port from shorts, back-emf etc using resistors etc as Rich says. If it's any consolation it probably wouldn't work to well since parallel ports will often miss laps if the car is travelling to quick.

This link has some instructions and circuits for enhanced detetctors if they help http://www.uracerweb.org/hardware/detector.htm

If you can afford a trackmate interface it's probably the simplest and most reliable option. We use them at our club and we've used both the optical version and dead strip version without any real issues (probably the deadstrip version is a little more reliable)

Hope that helps a little.

P.S. Trackmate can also be connected to USB via a serial to USB connector.
 

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Discussion Starter · #9 ·
Thanks,Rich, and Slingshotx.

The frustrating thing is that the lane that does work works perfectly, and the PC-Doctor program says the parallel port is working normally, so I suspect this is some kind of Driver issue, but I don't know enough to start fiddling in this area.

I will try the serial port when I can get a lead and a socket.

A member of another American site, a while ago, suggested that this kind of problem is 99% of the time caused by pins locking out because they interpret a contact signal as a "short", and that the fix is to put a 150 ohm resistor in each detector circuit.

Unfortunately, he didn't say how to unlock the lockout - and I appear to be in the 1% where it isn't the fix,as I've tried it and it hasn't made any difference.

I do take the point about usually needing some protective circuitry, but as Brent Carlson is so emphatic about which pins not to short out,I thought I might get away with it.

The thought did occur to me that LT2000 is quite an old program, and might be better-suited to an older version of Windows than XP Professional, which is what my old laptop has on it.

If I succeed in boiling the serial port, I really will throw in the towel and buy Trackmate and a new(old) laptop.

Regards,

David.
 

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I have used this program on my home track for three years without a single problem. It uses so little of a computer's resources that it would probably run on a Sinclair Spectrum.
I have used it on both XP and Windows 98 machines. It runs happily on both.

I can't help much with your dead strip problem as I use a light-bridge and sensors. I think that the program was meant to use these rather than the strip. Why are you so insistent on using the dead strip by the way? Wiring up 4 sensors is so easy even I can do it!

I don't know if this is any help but there is a port test facility built into the program. If you go to "edit" on the main race screen it is at the bottom of the drop-down list.

Persevere though, it is an excellent program and does virtually everything a home racer might need. If you want to try something even better then take a look at Race Coordinator LINKY which is also a free download and has refueling included.
 

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Rich Dumas
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When you use standard dead strips the car's motor is part of the circuit and that will cause a problem if you get the polarity wrong. If the polarity is backwards the counter will only work properly if the car is going slow. That happens because the motor is a generator when the car is moving. I measured the voltage output of a Scalextric motor at full speed, it put out 4.8 volts. If you were to put a volt meter across a working dead strip you would measure a voltage. If you put a short across the dead strips the voltage will go to zero because there is no voltage across a short. This change in voltage is what actually triggers a count. If the car's motor is generating enough voltage it would seem to the computer that the car had not even crossed the dead strips. If you reverse the wires that go to the dead strips the voltage from the motor is reversed and the problem goes away. With a split rail dead strip there is no polarity issue because the motor is not in the circuit.
 

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Discussion Starter · #12 ·
Thanks for the encouragement, Brian.

I just posted this reply but it seems to have disappeared into cyberspace.

I've tried the port testing utility in Edit, but although it said the ports were working in all configurations but one, - they still weren't.

I've gone over my split tapes and all my soldered joints again, and tried all the various configurations of the parallel port, and I've still got lane 3 working perfectly(pin12) and nothing on 10 and 11.

Maybe, I've just got a duff parallel port; pin25 wasn't working to begin with, so I used 23 as ground.

I'm going to try a serial connection.

If that won't work, I wondered if a PCMCIA card might give me a new parallel port - or perhaps I should just stop throwing good money after bad, and set the tills jingling at Trackmate.

From my all too brief experience with it, LT2000 seems ideal for home use - if I could just get it to work.

Several of the other available systems seem impressive but too complicated for someone who can only cope with electronics by regarding it as very very small scale plumbing; and who still harbours the suspicion that computers. are the work of the Devil.

I wasn't fixed on the split tape system; indeed I had just taken delivery of a bagful of I/R photo interruptors when I read about it, and thought I'd give it a try for its elegant simplicity, its low probability of boiling the computer's innards, and the absence of things to go wrong. ( Does anybody else hear hollow laughter - or is it just me?).

David.
 

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*** Leo A Capaldi ***
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Hello David,
Have you checked that you still have "Trackmate Sensor Compatability" ticked in Settings >> Ports ?

Power off, wait 20 seconds and power on will clear any port locks (which I have never experienced though).

Do you still have 2 out of 4 channels working?

Virtual Race System has a nice printer port test package - Linky

Leo
 

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David,
it seems there are 3 possible reasons for your problems:

1) the program itself is not functioning properly - extremely unlikely as it is such a simple one.

2) your wiring is faulty - again unlikely as you appear to have checked it.

3) As you think, the parallel port itself is cream crackered.

Before you spend money on Trackmate and adaptors why not try a different computer? Mine runs on a 10 year old+ Windows 98 machine which I picked up for less than £20. Ancient laptops are as cheap as chips and there are hundreds of them on a well known auction site. Don't get a Dell one though - they use a non-standard parallel port.
 

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Discussion Starter · #15 ·
Thanks, Leo.

I did check, and I tried the VRS port checker, but It seems to be only concerned with the pins VRS uses.

Brian, I think you have identified the elephant in the room. It is often the case that it takes someone looking in from outside to see the sensible way forward.

I guess i haven't really liked to face the reality that I've probably boiled the parallel port, and since I've changed to Mac for routine use, I didn't have another machine with a parallel port to try out.

You are right of course.Looking for an old, cheap and relatively disposable Windows laptop is the sensible next step.

David.
 

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Discussion Starter · #16 ·
Problem sorted. Lessons learned.

Bought an old Samsung laptop (even older than my old Think pad).

Did the Brent Carlson test with 150 Ohm resistor in series.

Connected to track (with 150 Ohm resistors on all lanes!).

It all seems to work just fine. No smell of burning.

I'm not even going to wonder whether it will still work tomorrow!

Lesson 1: Don't even think about shorting any pins on a parallel port without including a resistor in series.
Even without voltage generated by motor, parallel port's 5volts will damage it unless current is reduced.
150 ohm resistor should bring it down to 33mA, which should be safe.(my understanding of the vast amount of web browsing I have done in the last few days).

Lesson 2: If you think you might have cooked your parallel port. . . you probably have. Don't waste time and energy fiddling with everything else, until you've checked!

Lesson 3: If you do a split tape 'dead strip', and you have routed a wide slot (mine's 4mm),make the isolated section of tape at lest half the width of the tape, or even a little more.

Otherwise, Scalextric-sized pick up braids will need an exaggerated splay to make the contact.

Many thanks to everyone who offered helpful suggestions.

David.
 

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Rich Dumas
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I suspected that the resistors would be necessary, I was not sure of the correct value. Going to a higher resistor value would not hurt the ports, but with too high of a resistor value you would miss counts.
 
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