# Ho Slot car track, any tips



## slot_car_noob (Mar 1, 2009)

hello all
i am planning on building a slot car track on a 6x10ft board. i think i have a track plan going, but if you think that anything is not right, plz comment. a crude drawing is attached, and is NOT to scale. i am also going to bank some of the corners, any tips on that. i am set with wireing, power, and controlers. i am probably going to use all three generations of afx track on it, is there any downside to that.
thx


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## dlw (Aug 17, 1999)

One downside is that the Tomy Afx track has a deeper slot than the old Aurora L&J and Quikee-lok track, which could be a problem for cars with longer guide pins. If your running only tjets and TO's (Aurora or JL/AW), you should have no problem.


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## slotnewbie69 (Dec 3, 2008)

if thats the track you have,use it.but rail height and slot depth are gonna be an issue for you,and of course you will need the adaptor tracks to get it all to your liking.i think it is best to have all one style of track,to keep the flow even around your track.rail heights changing abruptly from style "a"to adaptor to style"b"to adaptor to style "c" can cause hang ups for the cars,and make alot of work for you when it comes to evening up all the connections.just my two cents...


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## slot_car_noob (Mar 1, 2009)

thanks for your input
i will probably use just two of the afx track generations, since i have the adapters


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## AfxToo (Aug 29, 2003)

I'm only aware of two generations of AFX track, the original snap together Aurora AFX style with the side locking tabs that break off very easily, with inward pointing electrical tabs, and the current Tomy AFX design with the zig zag rail at the joints. The Tomy design is far better electrically but the Aurora design is subjectively smoother with slightly higher downforce rails. If you have the Aurora AFX style track, plan on getting some locking (track repair) clips. 

The old Aurora Model Motoring track, sold pre AFX era, with the metal alignment pins and plastic locking keys, can be mated to Aurora AFX track with the appropriate adapter sections that were originally sold by Aurora and are fairly difficult to find. The Aurora AFX to Tomy AFX adapters are sold by Life-Like. As others have mentioned, the slot depth of the Model Motoring track is shallower than either AFX track. The Model Motoring track also has the worst electrical design of the three and is more prone to dead spots and in more need of extra power taps. Unless you have a ton of it and want to be very meticulous about how you prepare the connections, it may be more trouble than it is worth. The big upside of the old MM track is the wide variety of specialty pieces like cross over (straight and curved), cobblestones, little bumps, big bumps, y-tracks, etc. Only a small number of the specialty pieces were done in the AFX track.

You don't mention if you want 2 lanes of 4 lanes an dhow much investment you have in your current mix of track. If you are shooting for a 4-lane layout with bigger radius turns, banks, and reliable connections you may be better off starting with all new track pieces from one or more of the larger sets and donating your old track to a younger relative or neighbor kid.


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## AfxToo (Aug 29, 2003)

Here's some track layouts that would fit on a 10 x 6 table, just to give you a feel for what is possible in that amount of space. You can get a very decent sized 4-laner in that footprint...


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## AfxToo (Aug 29, 2003)

... and a few more ...


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## Jerzferno (Aug 19, 2007)

AFXtoo - What design program is that? Got a link?


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## AfxToo (Aug 29, 2003)

Tracker 2000, which unfortunately, is no longer available. There are freeware alternatives like this: http://www.uracerweb.org/ .


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## copperhead71 (Aug 2, 2007)

....WELL..since it's somewhat mentioned in this thread...which track system has the strongest joiner's(joint's ,tab's that connect one piece of track to another)


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## slot_car_noob (Mar 1, 2009)

*Infra Red LEDs*

thank you for those track plans, they are great. I was also wondering if anyone knew if i need resistors for the infra red LEDs that greg Braun talks about using for the lap counter. i'm not talking about the photo cells, but the LEDS that go above them. i have normal ones in now, but i want to go to the infra red so u cant see the light. Any help plz, because i can figure out how to wire the infra red LEDS!


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## AfxToo (Aug 29, 2003)

The IR LED emitters that Gregory specifies: RS Part No. 276-143 require current limiting resistors, as he shows on his site. He shows 470 ohm 1/4 watt resistors, which is a standard sized part that's easy to find. This recommendation assumes a 12V supply is being used.

LEDs are especially sensitive to over current. If you are using an LED other than one that someone else has done their homework on or if you are using a different power supply voltage, you'll need to find the data sheet for the LED so you know its maximum forward current rating. These can often be found online, usually as a downloadable PDF file, or it may be listed on the packaging or web site selling the part. Once you know this rating you can figure out the MINIMUM resistor that you'll need by dividing the power supply voltage by the maximum forward current rating of the power supply you will be using. 

R = Power Supply Voltage / Max Forward Current Rating

The Radio Shack part that is listed above has a max forward current of 100 milliamps, or 0.100 amps. If you use the formula above the minimum sized current limiting resistor would be: 12V/.100 = 120 ohms. That's the minimum. Using a larger value as Gregory specifies, a 470 ohm, will reduce the current even further, giving you a little more margin and probably prolonging the life of the LED a bit. Resistors generally come in standard values, so you need to pick a standard one that's above the calculated value. You could, for example, use a 270 ohm resistor with the RS LED listed above if you are using 12V. This would still give you plenty of protection margin and a bit more light intensity.

Whatever you do, make sure that the parts are designed to operate in the range of voltage you are going to use, and make sure you provide current limiting resistors if the parts do not have built-in current limiting. Make sure you run the calculations yourself if you are using a different power supply than what Gregory uses in his example.

One thing to keep in mind about IR systems is that you ideally want the emitters and receptors (photo transistors) to be perfectly matched to the same wavelength. The pair work best when the peak intensity of the emitter is aligned with the peak sensitivity of the receptor. Makes sense. You can buy matched pairs, like these: http://www.sunrom.com/index.php?main_page=product_info&products_id=247


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## slot_car_noob (Mar 1, 2009)

thanks for your help, Afxtoo. I am going to be needing to get down to radio shack now and get a resistor. I only need one, right. if i wire it into one of the wires from the power pack i should be all set, i think. Also, for anyone who uses lap counter 2000, i have it set up, but it seems like the time in big letters that it shows is two laps back. why is that and does anyone know if there is a setting to change that. Thx


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## AfxToo (Aug 29, 2003)

You could use a single resistor and wire the LEDs in series, but you will have to use a different sized resistor because you'll have to compensate for the cumulative forward voltage drop of the IR emitter LEDs. These devices drop a lot more voltage than conventional diodes, in the 1.0V-2.0V range versus 0.5V-0.7V for regular diodes. I didn't account for this in my formula, which was less of an issue because only one LED was involved per leg. With a 12V supply and all LEDs wired in series with a single current limiting resistor, you would use a 150 ohm 1/2 watt current limiting resistor for the Radio Shack 276-143 IR emitter, assuming you want to drive 4 LED emitters at 50% of their rated current.

If you use the same Radio Shack 276-143 part with one current limiting resistor per LED and the LED+resistor pairs wired in parallel like Gregory shows on his site in the Lap Counters section, you would need to use a 220 ohm 1 watt resistor on each leg.

This brings up a point that that I neglected to mention earlier, which is that you may need to increase the resistor value to limit the amount of current going through the current limiting resistor to stay within its power rating. If you use a 220 ohm resistor for each parallel leg you will need to use 1 watt resistor to drive the LED at 50% capacity. A 220 ohm/1 watt resistor may be a little harder to find at Radio Shack, but still cheap, less than a dollar each if they carry them. Using a 270 ohm resistor would allow you to use a 1/2 watt resistor, which you are more likely to find at Radio Shack. This reduces the LED current to 40% of max so the IR light intensity will be slightly lower. Don't use a 1/4 watt resistors for either of these combinations, unless you are using an even large resistor and getting sufficient performance at the reduced light intensity.


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