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Post by estill on Nov 29, 2011 8:28:33 GMT -7
I've been a lurking around here for about a year, so It is probably time to introduce myself. A couple of years back I used to drag race 24th scale. Last year I received the AutoWorld set for Christmas. So I build a collapsible table for the garage, and we can set it up in about 30 minutes. While it's fun I have been longing for bracket racing.
When I found out about the Arduino a couple of weeks ago, I decided it was time to build my own timing system. I'm not going to go into a sales pitch about the Arduino, other than it is a USB programmable device that has multiple inputs and outputs for running home built circuitry. By the end of this week I should have everything to basically build my own miniature Trick Track like system. My plan is to have incremental times display for Reaction Time, 1/2 track, total ET and a speed trap. Each lane will have a scoreboard with win lights. This leads me to my first question; what happens to the yellow lights when some red lights? I have been attending drag races for longer than I care to admit to, and I can't remember if they stay on or go out when the red light occurs.
The second question I have revolves around the track itself. Since I want it to quickly break down, I was planning an sheeting my table with MDF with a slot cutout for the track to sit in. Looking around here it looks like the better plan would be to just cut slots in the MDF and race directly on it. What are people using for the rails? rebar tie wire looks very attractive for the price, but my fear is it rusting. I've seen reference to electric fencing wire, and I have found a wire composed of 60% NICKEL, 16% CHROMIUM, 24% IRON. Are there any recommendations for what to use?
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Post by TGM2054 on Nov 29, 2011 21:49:50 GMT -7
WELCOME TO THE PARTY! To answer your first question.......... I can't remember my self! I never red light (my reation times are too slow). I think, the yellows go out and the red stays on, but don't quote me. As far as your track goes, one advantage to routing your own track is that you can put more space between your lanes, makes it a little more realistic and the cars aren't bouncing off of each other. As far as power rails go, the tie wire is what a lot of people use, I've also heard of using the wire to hold up drop ceilings, copper tape, just about any thing that conducts electricty. you might check with Khim at Slot Car Express, he's got power rail among other things. You'll see him on here from time to time as Sir Slotalot. He can give you better advice on the power rails than I. Let us know how that timing system works out. I'm in the process of looking at them myself, the financing of one is the problem for me right now.
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Post by estill on Nov 30, 2011 10:05:14 GMT -7
Thanks for the reply about the tie wire. It's cheap so that's the route I really want to go. I've looked at the Slot Car Express stuff, and I don't want to spend that much. I already have a working track that I can drill holes in.
I'd like put enough spacing between the lanes to run the sensors horizontally.
I'm going a little overboard on my timing system. So far I have about $200 into the supplies, so it can be a stand alone system. I will post pics when the track is complete. Neither the circuitry or the programming is overly complex. It is just repeated over and over again. If anyone is interested I am willing to share what I have put together so far.
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Post by Bananasmoothie1975 on Dec 20, 2011 2:13:57 GMT -7
Re power rails, also look for flat stitching wire (I use 2.5x0.5mm)
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Post by estill on Feb 17, 2012 11:13:59 GMT -7
I have everything stock piled to start building my track now. What is the accepted distance between the stage and starting line beams? Likewise what should the distance be between the start and end of a speed trap? I can do the math and make it scale, but I am wondering if there is an accepted standard.
Since my last post I have been busy burning up two starting line track sections for the A/W set. While I was not able to get an accurate place to tap the circuit board for determining reaction time, I was able get my code figured out for displaying E/T and Speed. I also have a tree built that I am starting to write the code for.
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Post by Bananasmoothie1975 on Feb 18, 2012 3:17:15 GMT -7
Last time I looked the speed trap was 66ft, which is 1/20 the total distance.
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Post by estill on Feb 27, 2012 19:56:27 GMT -7
I have a breadboard setup with the initial circuit for the LCD timing towers and the Tree. HI put together a small video to show off what I have so far. Since I can't get the video to embed properly, here is a direct link to it:
At startup the LED's on the tree flash in sequence then come on steady. This allows you to verify wiring and that all the LED's come on.
I know now what You Tube does to overcompress videos. The first screens are:
Select Tree:
Pro .400 - 1
Sports .500 - 2
When you select the sportsman tree you get:
Quick Race - 1
Bracket Race - 2
Index Race - 3
After bracket or index you are prompted to enter a dialin. The screen shows X.XXX with an underscore cursor. The X's are replaced with numbers as they are entered on the key pad
Thought's, Comments, questions?
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Post by kiwidave on Feb 27, 2012 20:21:32 GMT -7
Very clever. Looking real good.
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kbuck
Pro Stock
"THUNDER BUCK RACEWAY"
Posts: 437
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Post by kbuck on Feb 28, 2012 12:50:15 GMT -7
This is a man on a mission. BRAVO!
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Post by Deleted on Feb 28, 2012 14:25:47 GMT -7
This is looking great! I'm very interested!
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Post by estill on Mar 9, 2012 12:06:27 GMT -7
I wanted to make a quick update. I have been down with a bad tooth. So progress has been slow. Using the bread board setup, I was able to complete the light sequence for a Pro (.400), Sportsman (.500), and a Bracket Tree. I was going to post a video of the pretty blinking lights, but I knocked some of the wires loose and it was too much work to put the bread board back together. Never try to do electrical wiring while on vicoden.
Over the last couple of nights I have been working on setting up the permanent circuit board and soldering it together. About all I can say is that trying to keep the wiring neat and tidy makes for a very slow process.
I'm hoping that now that this tooth have been removed I can get my head cleared up enough to go back to using power tools and build a track.
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Post by Deleted on Mar 11, 2012 11:31:58 GMT -7
I'm hopeful that you will be willing to help a fellow racer out with replicating this system once its up and running.
I was hoping to be able to tap the AW system as well, but really like your stand alone system over and PC based solutions.
Very nice work!
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Post by estill on Mar 13, 2012 7:38:08 GMT -7
Ninjatak is holding a place for my wiring schematic and source code in a yet to be determined future NTRA News Letter. If anyone want a sneak peak, or wants to join in the fun of debugging code, send me a PM and I am will share it now.
A couple of things I have figured that that have me really excited:
Sensors can be made using cheap LED's from Hong Kong/Ebay. If you shine the same wavelength or shorter (it's early I think this is correct) into an LED current will flow. In other words if you put +5v into the positive leg of the LED, and put a volt meter between the - on the power source and the - led on the LED you will see the voltage change as the amount of light hitting the LED changes. (Don't connect the - of the power source to the - of the LED it will pop.) If you connect the - leg of the LED to something like Radio Shack's Quad Comparator Chip, you get a digital output of either +5V or 0V as the voltage changes.
To make the transition as quick as possible you setup you sensors in pairs of LED's. One as a sensor and the other emitting light. You can do an over/under track setup with a light bridge, or I will be putting my illuminated LED's in the middle of the track shining out towards the sensor hidden in the guard rail.
On the Adruino MEGA you have 6 pins that can be setup as interrupts. If the voltage changes on any of those pins the main program will pause and run a defined function. I am using 2 for staging and two 2 the starting line/red light function.
Even when running through a sequential check sensor 1, check sensor 2, etc loop of code for the 1/2 track and finish line sensors it looks like I will be well under 100 microseconds of resolution.
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Post by Doug412 on Jul 24, 2013 8:34:00 GMT -7
Hey guys, anybody ever try a garage door safety laser for shooting the timing systems? Does anyone know if lasers would work? I'm gonna try it when i get paid again.. Ugh this system i'm working with is driving me crazy.. It only picks up the second photo cell  Not happy! ANY Insight will be helpful! Thanks Much... Race On Doug412 |
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Post by jjwallace on Aug 2, 2013 9:36:04 GMT -7
Doug I don't know if I can help or not. I am still having trouble with mine. It will go 20 runs without a problem, then 5 double counts in a row. It's crazy. When you say second photo cell, do you mean the one at the end of the track? It's not picking up the one at the start? If that's the case, are you sure the start line sensors aren't broken. The reason I ask is because I had one go bad and had to replace it right before my race. You should be able to make the light on the calibration box go on and off with the knob. Like I said, mine work works well most of the time, but still this nuisance double count issue. Still haven't changed my lighting yet. Getting ready to do that. Let me know if I am understanding your problem correctly or if any of this helps. Just now saw your post or I would have replied sooner.
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Not happy! ANY Insight will be helpful! Thanks Much...
