View Full Version : Lap Counters

2002.01.15, 07:49 PM
We're definitely going to need some sort of lap counting device. What do you guys use?

2002.01.15, 08:01 PM
The LHS's track uses various height "flags" on the antenna's that break infra-red beams and a cable to the parallel port of a PC running some sort of software (I can get the name of it) keeps track of lap times and statistics.


2002.01.15, 08:55 PM
Also see what other types of systems that program will access... I am currious if I can use it with my PC-Gadget... http://www.pcgadget.com (they gave me a cheap one so I plug it now and then hehe). Since the PCG can also control stepper motors and solenoinds etc.. I plan to add a up/down starting gate kinda like a bmx/ dirt bike race gates etc. or a horse gate.

But the antenna flag and laser trip is the simplest way of doing it.. as long as you have a way to physicly plug the light sensors into the PC (the lasers can just be a cheap 50 cent laser pointer). The PC Gadget is just my way of doing it with out haveing to get a schematic and build one.

When I find, or create my own, software to operate it, I plan to complete my LAP COUNTER building page... THere are already a few pages out there that say how to make one like this though... but some require expensive hardware. -- if I find the url I will add it to this post.

2002.01.16, 01:24 AM
50 cents for a laser ponter?!
The cheapest I've managed to came across were 15-20 USD. (apparently that kind of novelty items are not a big hit around here)
There is a lot of slotcar timing software out here on the net, get one that uses the parallel port and you're set.
The software doesn't know you're not "stuck in a rut" ;)
IR would suffice but would be unreliable in bright daylight, maybe even if you have a lot of fluorescent tubes to light your track.


2002.01.16, 02:00 AM
On **** you can get the cheap laser pointers virtualy free... they are all over the place... now the GREEN ones thats another story 100 or more bucks hehe... egad. would be nice though (you can see the beam at night like a line into the sky).

Aint you getting a little carried away with the chat filter Mini-Z? E B A Y being sensored is a bit much ;). Compition is a fact of life, the only reason to hide it would be if their service and prices were better........ surely you can prove otherwise.

2002.01.16, 09:51 AM
You can go here:

And bid on the auction that I'm bidding on too... guy has 1000 laser pointers for auction. BUT they are about $5 each to ship, so be careful.

Only reason I bid is because they come with spare batteries and I have another pointer that needs a set so it's like two for 1.


2002.01.16, 12:32 PM
5$ is still WAY too much.. keep looking till you find it for .01 cents Dutch auction, with a 2.50$ shipping to usa... It pops up now and then.. no idea who sells it.. and I once bought Laser pointer batteries on there for 2.50 for 20 batteries... and I paid too much.. dont pay what the hardware store charges for those batteries.. almost 2$ each.

2002.01.16, 09:16 PM
Lasers and a PC sound good, but where can I get more info? We have 3 cars now, and we're keen to race!

2002.01.17, 03:44 AM
I saw one set that was called "The Simpson lap counter" or something. I couldn't get to the site but here's the link regardless.
If I recall correctly it was using serial port and a bunch of special electronics. He's selling those so no schematics available.
If you have a friend that is capable in electronics he might be able to whip up a laser and detector system in no time. search the web for slotcar lap counting systems, I came across a lot of free software and schematics.
The point is that you set up as many laser beams as you have racers, detect tripping of the beams and send that into the software just as it were a magnetic switch on a slotcar track.


2002.01.17, 10:13 AM

Lap counters and timers for slot cars ar a different animal all together. Slot cars remain in the designated lane for the duration of the race. To time them via lasers or directional IR is quite easy from a logical point of view. Most tracks have a bridge where the sensors reside, or they can be placed under the track rails.

With Mini-Z's and other RC cars, you are not lane bound, so the extended antenna would be the one choice.
I remember when I was in the U.S., I attended a race meeting in Beaverton, Oregon. They were racing 1/10's and 1/8 scale nitro's. They did their timing via a small independant signal generator placed within the car. It ran on watch batteries. each car was desingated one. It remained in the car for the day.

If I remember correctly, these SG's had a binary signature and a low power TX capability using K-Band frequencies. At this track, all they did was hang a reciever wire over the start/finish line and this would trap or log the signals. These SG's were small too, but I guess they would be a little large for a Mini-Z, but this is over 5 years ago that I saw this.
The charting was PC based via a Serial port.

With semiconductors shrinking in size and power consumption, I am sure a similar system could be made for Mini-Z's.
Now, I knw people are going to comment on weight, but they could be made fairly light and this wouldn't hamper the performance too much, if at all..

Unfortunately, to impliment such a system costs money and the only way to pay for something like this is via an established club that (as most do) charges for racedays.

Perhaps someone who subscribes to the Radio Controlled Car Action magazine can dig something up on companies that specialise in this kind of technology.


2002.01.17, 02:18 PM
Look at the page : http://www.slotrace.com/laptimer/hardware.html.

The light path has to be moved to horisontal as opposed to the vertical as on the page above. Note that the electronis is very limited and cheap and uses High power LED - not lasers !

Software is also available on the page.

I will shortly being building a system based on the page above and report once i have it working

2002.01.17, 02:46 PM

Just as I had said in my earlier post... a lap timer based on LRD's is great for anything running in a slot, or for a solo car on a track.

Waste of time for Mini-Z type racing..


2002.01.17, 03:41 PM
Okay - because the LDR are to slow or ?

Could try with a setup based on a photo diode but pretty much the same setup on the op-amp side.

take a look at http://miniz.peachpuff.com/gallery.htm and see the optical path and breaking can work just fine

2002.01.17, 04:14 PM

Nothing to do with the LDR's strobe speed or anything like that.

Picture this:
A track with 6 Mini-Z's zooming around.
6 LDR's waiting to provide lap times.
How do you enforce that each Mini-Z is going to pass over the correct LDR on each lap?
With slot cars, they remain on the same rail on the track all the time, thus the LDR dedicated to car in Slot 2 will always time Slot 2!

RC cars do not run in slots, theyre always all over the track... so these 6 LDR's are going to time anything that crosses their path.. causing sheer confusion.

The variable length antenna could work with LDR's as mentioned previously by Jeff in this Thread.



2002.01.17, 05:03 PM
Instead of the variable lenght antenna let me suggest a "flag" at different heights on the cars in question.

The trick is then to ajust the circuits sensitivity so that a barebone antenna dont trigger the circuit but a flag(= total light cutoff) will trigger the circuit.

The diameter of the LDR is like 5 mm so it should be workable at least for the standard (thin) antenna

Agree ?

2002.01.17, 05:39 PM

Agreed! :D

But it's untidy...


2002.01.21, 01:24 AM
I know what the differnce between slot- and mini-Z cars is ;)
I was going for the quick and nasty solution henckel also pointed out. Flags in the antenna, lasers and photodiodes. I did find a 10th scale lap counter system on the net, nice, sophisticated, expensive as H E L L.

I recall someone using the same system for mini-z timing. If my memory is correct it was 60g for the "self powered" transponder.

As I and the guys I'm racing with do not have the urge to spend the around 4000 euro for a lap counting system, it has to be quick and nasty...