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minizmaniac
2003.04.30, 04:46 AM
i have seen threads about people building their own track timer and i want to do this. but first i have a few questions.

1) how much does it cost for a six car track, not including the computer but including everything else.
2) do you have to have extensive electronic knowledge, i basically have no programming knowledge
3) i have seen that you basically need a power supply, laser pointers and photo transistors. how do you a) connect the power supply to six lasers b)where do you get the wire to connect the computer to the photo transistors and how do you do it.
4) can i make the whole thing mobile and easy to carry (i would probably let our local track use it after i perfect everything)

thank you for any help:)

Draconious
2003.04.30, 02:25 PM
It should be fairly cheap, laser pointes can be had under 4$ea on ebay.. in bulk, and if you look hard enough once in a whle some one will sell them for almost 1.25ea shipped... very very cheap laser opinter but all you need it to do is sine about 3 feet, onto the sensor... I am sure it would even be possible to make a lap counter using only one laser pointer, if you divided up the beam with some fiber optics or someting, then the beam would be narrower or someting.. who knows. weaker too though.

Sensors can be aquired very cheap...
http://www.sciplus.com/singleItem.cfm?terms=3325&cartLogFrom=Search


As for instructinos I think some one made some how too's but did not finish them or somting.. i forget maybe I just didnt finish reading or viewing the photos ;).

BobT
2003.04.30, 02:54 PM
There is an excellent "how-to" I found on a slot-car site.

http://www.hoslotcarracing.com/image/LapCounter.gif

They use a laser system. Their system is vertical but the same system is used horizontal for Mini Zs and Micros.

See http://www.crottyscustomrc.com/crottysproducts.htm for a plug and play system for $400. Or just look at it to see how to convert the slot-car counter to RC.

Dirtbag
2003.04.30, 08:56 PM
Hey Bob this is Wes, didn't know you were on the boards.

BobT
2003.05.01, 08:55 AM
I'm lurking almost everywhere.

Dirtbag
2003.05.01, 04:17 PM
lol.

mlepage
2003.05.06, 12:58 AM
I built one. My page on it is here:

http://www.antimeta.com/projects/miniz/index.html

Just today I finished remaking the laser-holding upright in machined aluminum. I haven't taken photos yet, I'm still getting it back up running.

Here's what you need to know:

Get a lot of laser pointers. They're cheap, but they're flaky. I've had some die on me. Best place to get them is from a dollar store. Search around till you find a store that has them. They were $2Cdn for me.

You can get IR phototransistors from Radio Shack. Just less than $2Cdn each.

At Radio Shack, you can also get a power adapter (typically 4.5V), a power jack, a switch, a parallel port connector, hookup wire, and whatever else you need. You can probably get it cheaper elsewhere, but if you're just a hobbyist then Radio Shack is convenient.

Your gantry has to be sturdy. My wood/aluminum one wasn't sturdy enough, so I am redoing it all in aluminum.

It's also extremely helpful if your gantry cannot be touched. That is, if cars cannot hit it. My newer gantry is like this, it has pin-like supports that go between my track barriers. Depending on what your track is like, you should strive to make the gantry immune from impact.

Finally, the lasers have to be aimable. There are many ways you can do this. Originally, as a quickie, I held them in place with elastic bands and shims. I wanted to use some sort of clamping mechanism. Ideally you'd have tuning screws. My new upright has tuning screws.

It's probably best to keep the lasers in the tubes. Originally, I tried to remove them. Now I am keeping them in.

Powering the lasers... you could just use batteries, and unscrew them when not in use. But AC power is nice because it is cheap and actually makes a better beam (batteries are weak). Just wire the jack to the switch, to each laser, in parallel.

I'm thinking now, if you have many lasers (say 6) but don't always use them all, you probably want a switch for each individual laser, so you don't wear them out prematurely.

So the lasers are easy. They're completely separate from the phototransistors.

The phototransistors are wired to the parallel port. Each negative lead goes to pin 25, and each positive lead goes to a different pin on the parallel port. Wire them to the parallel port connector, then you can just use a regular parallel port cord to connect to any computer.

Use this shareware software:

Virtual Race System (http://www.virtualracesystem.co.uk/)

They have a schematic showing you which pins to wire to the phototransistors.

Once you run the software, and plug the parallel port to the wired phototransistors, you are in business. Shining lights on and off the phototransistors will be picked up by the software. You can test all of this without even having lasers.

The lasers just provide a beam for a flag to interrupt.

As for making all of this portable, you'll just have to sit down with a sheet of paper and make a design and try stuff.

You're biggest problem is going to be having the lasers misalign during a race, screwing everything up. The gantry and aiming system have to be sturdy and secure enough to make this not happen.

I'll be updating my page in the next few days once I get back up and running.

minizmaniac
2003.05.06, 01:16 AM
thank you very much for the info, it was actually your page that inspired me to do this.
i was actually having switches to each individual laser becuase sometimes i might want to just race my brother and other times i was thinking that i would take it to my local track to use. and it would be something that i could put in the trunk of a car, not tiny but not something that has to be bolted to the floor, i am sure that i can figure something out.

one question about the software, do you have to buy it is it something you can download? i would like to be downloadable but i dont mind buying it.

and does a 1/10th scale antenna sleeve trip the counter becasue i was thinking of using these as the attachment of the flag because they are cheap, can be used with almost any car, and they are easily removable.

thank you for all of your help;)

mlepage
2003.05.06, 01:32 AM
OK, first go to the software site and check out the software, their advice on wiring the sensors, schematics, etc. The VRS software is shareware. You download it, use the limited version, and if you want to register you get more features. I haven't registered yet but probably will.

There are a few apps: a lite version, a less-lite version, and a test app. Get them all. The test app is great for calibrating the lasers.

There is other software too, but it probably will have different hardware connections.

You've seen photos of my gantry. The wood uprights are 0.75" thick, and the crosspiece is 1" hollow aluminum square. Imagine the clamps were bolts. Then, to disassemble my gantry would be to remove those bolts to separate the uprights from the crosspiece.

The crosspiece is 2' long. The uprights are 1' wide and 1' high.

I run the wiring through the crosspiece. But at both ends, I made little plugs for the wiring, so I can disconnect the wiring.

So really, my gantry is fairly portable as it is on the page right now. The biggest problem is the poor laser mounting and mess of wiring.

My new gantry, which will have photos posted in a few days, is less portable because it is solid. Same crosspiece, and same upright dimensions, but now the uprights are also aluminum and are bolted to the crosspiece. It's difficult to unbolt them, but if it were made to be easy, it would still be portable.

Realistically, if I wanted to transport my gantry, I'd just put it in the back seat fully assembled. It occupies a space 1x1x2 feet.

My new laser aiming is all machine screws. It's hard to describe so wait for photos.

The Mini-Z antennas do not trip the lasers without a flag. Dunno about 1/10 antennas. It may trip some lasers and not others, if their power is inconsistent. (I find the cheap quality inconsistent.)

My new gantry is not bolted to the floor, but my track barriers are. I put more blocks to really stiffen the barriers in that area, leaving two little hollows between the barriers. My new gantry has bolt feet like peg stereo stands (I don't know what they are called), like it is standing on two pins. Those pins fit into the hollow. Cars hit the barrier, which doesn't hit the pins. Again a photo will show this.

mlepage
2003.05.06, 01:37 AM
I suppose if you were really serious about portability, quickly and easily, you could make a gantry like my new one, that folded in like a collapsible table. That is, each upright (leg) would fold in on the crosspiece (tabletop).

This would require quite a design and execution. That's the tradeoff, spending a lot of up front time to save time later. Probably easier to just bolt it together and make the bolts easily removed/replaced, and spend the few minutes disassembling/reassembing it.

Or, you could go with a different design and have no crosspiece. Imagine two little towers, one with only the sensors, the other with only the lasers. You place them both down, run a parallel cord to one, maybe a power cord to the other (or maybe it is battery powered). You calibrate the lasers on one tower to point to the sensors on the other. Done. I'm thinking two little towers like your PC speakers.

minizmaniac
2003.05.06, 01:42 AM
the size of the gantry on yours was about what i was thinking, and it would be fairly easy to transport something that size. i am interested to see these new side supports they sound really good, where did you get them? and are they possible to make with basic tools?

mlepage
2003.05.06, 01:42 AM
You power the lasers with either 3 small batteries, or a single power source using wires (either a battery or AC transformer).

So you can cut power by disconnecting the batteries (usually just removing the end cap is enough) or wires.

Also, you need to keep the push switch down. So you can cut power by letting that switch go up.

I use a little plastic tie wrap to hold the switch down. You can slide it just off the switch to release it, then slide it back over to turn on the laser.

The drawbacks to these two methods of switching the lasers on and off are twofold.

First, they are less convenient than just flicking a switch.

Second, they involve interaction with the laser itself. This has the potential to misalign the laser. This may not be a big deal if your lasers are easy to align.

minizmaniac
2003.05.06, 01:44 AM
i think that it would be too much of a hassle to design and make such a complicated folding thing, i think that if i have something that is only 1x1x2 i can make all of the cables easily disconnected and just put everything in the back seat of a car.

mlepage
2003.05.06, 01:48 AM
I made my aluminum gantry in about a day of careful measuring and manufacturing. I suppose you could go faster, but I wanted mine to be carefully made. And I was sick.

The aluminum I got from Home Depot, just hollow square for the crosspiece and L angles for the uprights.

Everything is done using basic hand tools. For the crosspiece, cut to length using hack saw, and file end.

For the uprights, cut two lengths of L angle with hacksaw, and file. Join them into a T. Cut a notch out of the top so the crosspiece can join. File.

Drill holes with a metal-cutting drill bit. File.

Assorted bolts for holding everything together.

I borrowed a tap/die set to tap one hold for each laser for horizontal alignment. That's great but I did wonder if I could just drill a hold and glue a bolt to one side and use that for threads instead.

I will post pictures within a few days. If anyone's interested I can give exact measurements, but it should be pretty obvious.

mlepage
2003.05.06, 01:51 AM
1x1x2 is a small footprint.

By all means, make the parallel cable and power cord plug into sockets so you can disconnect them. It's only a couple of dollars for the sockets, and a little bit of soldering to connect them.

When you do stuff, measure carefully. Use a metal ruler, a square, and a 0.5mm mechanical pencil (for a fine line). Clamp everything so it doesn't move when you work on it.

mlepage
2003.05.06, 01:57 AM
I made it so the bottom of my lowest flag is 3" high. Each flag is 0.75" high. And flags are right on top of each other.

This allows electrical tape (3/4" wide) to make a nice easy flag.

So I have 6 flags from 3" to 7.5".

Lasers are centered on those flags. So the first beam is at 3.375", the next at 4.125", etc.

I found those heights to work well with Street Racer and Overland. You won't get the lowest flag on an Overland, and the highest flag might require a longer antenna (or maybe just try a quick and dirty toothpick extension). But it should suit most cars.

minizmaniac
2003.05.06, 02:00 AM
i will go to lowes and see what they have for the uprights and cross peice. it seems pretty simple but it just requires time, i was thinking of using electrical tape as well for the flags. (great minds think alike);)

Draconious
2003.05.06, 09:27 AM
I say instead of centering the laser on the flag, put it a little below center... so when the antenna rocks back and forth side to side its still in the range of effect.. and less likly the flag above it would trip it.

minizmaniac
2003.05.06, 04:25 PM
drac, that is a good idea, and i was also thinking that i could somehow make a 3d flag and so if someones car was pushed so it went over the line sideways it would still trip the laser, i would make the flag look like a T, looking from over the flag.;)

Draconious
2003.05.06, 04:40 PM
What I keep searching for is a REALY cheap table top, grocery store style bar code reader... one that can read fast and reliable enough for a mini-z to fly over it at full speed of course.

With this system every racer could use their own code for their lap counter stick a freshly printed sticker on the bottom of their car and never worry about removing it... they could walk upto the pit area PC, and wave their car over another scanner and get all the track data on their car etc...

I know such bar code scanners exist... just not cheap or affordable... they can scan liscense plates from a distance they should be able to scan mini-z chassis bottoms... and might need 2 or 3 side by side to get a full track width... wich would also help in registering 2 or 3 cars over the line at once...

The average grocery store bar code reader is unlikely good enough so this idea will likely never happen...

mlepage
2003.05.06, 09:39 PM
I thought of the swinging flag. I believe in practice it doesn't matter too much. With 0.75" flags, it can't go up and really doesn't swing down far enough to trip the laser beam below it.

I just bring my car up to the gantry, put electrical tape on the antenna so the dot is in the center, then squeeze it tight so it stays on.

The trouble of making a T shaped flag is not worth it. You're never going to go across perfectly sideways. Even the slightest angle will trip the laser. Even if it could happen in theory, it's not worth worrying about.

eirikr
2003.05.07, 04:08 PM
This is the best link that I found on how to construct a laser timer. Have link to the shareware too.

http://www.schumacher.clara.net/laptimer.htm

minizmaniac
2003.05.07, 05:19 PM
yeah ive also been using those instructions but from the original site;)

mlepage
2003.05.08, 05:46 PM
OK, I have as promised updated my track timer page with photos and description of my new aluminum gantry upright that holds and aims my lasers.

My Track Timer Page (http://www.antimeta.com/projects/miniz/index.html)

I'm rather happy with how this little project turned out. I did it with hand tools and it's not really that hard to replicate if you are so inclined.

PS: Check out my index page again soon, I'm going to put up photos of my Overland "powered body mounts" mod within a day or two. That mod would also work on a regular Mini-Z.

minizmaniac
2003.05.08, 08:13 PM
wow! those are pretty well thought out mounts.

i went to raido shack today and i found basically a laser pointer that is just the vital parts in a small round case, that has 2 power wires coming out of the back of it, i think this is what i am going to use instead of laser pointers because the cheapest i could find laser pointers was at least 10 bucks and these were only 5

mlepage
2003.05.08, 10:23 PM
As long as it works. Be sure to post photos when you have something.

latency
2003.05.08, 10:34 PM
Originally posted by eirikr
This is the best link that I found on how to construct a laser timer. Have link to the shareware too.

http://www.schumacher.clara.net/laptimer.htm

Looks familiar! Sanj sent me an email some time back and asked if he could pull the pics and stuff from my site to post on his, I said "Of Course!". That is definitely the point, to share the info! :)

As mlepage mentioned, this not a terribly difficult thing to do, and there are numorous ways for you to implement the designs. I believe I am on about the 3rd design of my timer, which has changed considerably since I got the first emails from mlepage asking for some tips before he jumped into the project with both feet. I originally got my ideas from http://www.itsallbutstraw.com but did not see everything that I needed so I went ahead and put up a very quick site to assist others if they decided to do the project.

Again, as mlepage suggests, spares of everything are handy, because undoubtedly at 3am when you are soldering or modifying your design, something WILL break. Save yourself the additional trip. :)

If you are considering this project, do it. It is cheap, fairly easy and very rewarding once you start hearing the pc keeping your times!!! :D :D

mlepage
2003.05.08, 10:51 PM
Yes props to latency for the helpful advice. I did use his site, and the itsallbutstraw one.

If you're hesitating because you think it's complicated, let me describe how you can make a lap timer for one car in literally minutes. It's that easy! Here's how.

You need only a computer, an IR phototransistor, a parallel cable, a cheap laser pointer, electrical tape, and a plastic tie wrap.

First go to the VRS web site I linked earlier, and download and install the free (shareware) software.

Next tape around the phototransistor so it's like a tube with only the top exposed, for the laser beam to shine in. Then, tape the phototransistor leads to pins on the parallel port cable: long lead to pin 25, short lead to pin 13.

Plug in the parallel cable and run the software. It should detect the signal from the phototransistor. Shine in the laser through the hole in the electrical tape tube, and you should see results on the computer.

Now just use the tie wrap to hold the laser's on button. Put the laser on one side of the track, and run the parallel cord to the other side of the track. Align the laser into the phototransistor.

Now you can race around the track and time one car (at least until the batteries in the laser wear out). You can do this before you do any gantry building, which is only necessary if you want more phototransistors and lasers (for timing more cars).

Doesn't sound so bad, does it?

mlepage
2003.05.08, 11:00 PM
Latency, new pics of your new lap timer?

Consider linking my page on your racing news site.

Hey, you have a baby girl! Me too, six months, first kid.

minizmaniac
2003.05.09, 12:50 AM
ok so i am pretty much ready to start collecting my materials, but when i went to raido shadk earlier i did not see any phototransistiors, where did you guys get yours, and for how much

and if i havent already said it, thank you for all of your help;)

le-manz
2003.05.09, 03:20 AM
Theres another free piece of software called laptimer2000 out there. I use it with much succes even though it currently only supports 4 lanes. Never got my pc to work with more than 4 anyway:rolleyes:

Anyway I think on this one it's a bit easier to read the laptimes during a frentic race because of the BIG numbers and more ccolors compared to vrs.

go here:

http://www.gregorybraun.com/LapTimer.html

mlepage
2003.05.09, 02:32 PM
The IR phototransistors are Radio Shack part number 276-145A.

minizmaniac
2003.05.09, 02:48 PM
thanks for the part number, i might start to collect my parts this weekend:D

latency
2003.05.09, 03:36 PM
Hey mlepage, I wish I had new pics! I have been so busy with the new baby, that I barely have time to even check these forums! :p

I am hoping to get some new ones here soon, time, yeah that is what I need. :)