Homemade Timing

[Nor Cal Mike]

Hi there was a couple of threads going on in the old board that got locked up because of the move. I along with Wolseley Hornet and Rocky were working on home made timing systems using ideas put forward by Rich D. I am reopening the discussion here so that it can continue.

As refresher, Rich offered two alternate ways to trigger a count similar to a conventional dead strip but using only one side of the track power circuit as the conduit for the count. Rich offered up drawings of two style set up one being an inline dead strip and another being a split rail design that actually leaves the car under power as it rolls through the counting strip. Rocky has successfully used the in line dead strip, David (Wolelsey Hornet) has successfully completed a split rail and today. I successfully (well sort of) used an inline strip on one of the lanes of my track. I say sort of because I am occasionally missing counts. I was testing my split rail made from printed circuit board and only had the solid copper type telephone wire that I am using twisted together in a temporary wiring set up. I am hoping that my problem is simply due to a poor connection and that if I solder the joints together, the counts will become more reliable. I can't find any pattern to the missed counts. They happen on different cars with different guides and differing softness of braid.

Here is a pic of my PCB split rail. The main body of the rail is connected to the positive side of the counting circuit going into the computer.


In the systems that Rocky, David and I are using, we are using pins 10,11, 12 &13 of the parallel or printer port for the counting side of the circuit and Pin 25 for the common (ground) side. One of the counting wires from Pins 10,11,12 &13 go to each lane. with Pin 10 going to lane one, Pin 11 to lane two etc. You should run separate wires from each lane back to pin 25 ground. David wound up using Pin 23 on his as the Pin 25 would not work. A 150 ohm resister must be used in each of the counting wires. My resisters are rated at one watt and 50 ohms.

I'll add more later.

[HomeRacingWorld]

Glad you are bringing this back. Thanks sir.

[Wolseley Hornet]

Mike,

What I found was that once you're satisfied that the connections are ok, and that the pickup braid is contacting both sides of the split, you have to fiddle about with the 'Settings' on Laptimer2000.
I finished up setting the Timer Resolution for 5ms, and the Debounce Delay for2000+Millisec.
The latter seems to have stopped double counting, and most of the time I think it is working well.
I have the sneaking suspicion that in really competitive high speed racing there is still the occasional missed lap, but as my track is just for fun it doesn't really matter.
I suppose things would be different if this was a commercial track with high-stakes racing going on; but I've no intention of ever getting involved with that sort of activity.

Maybe I should confess that in the depths of my despair when I had fried the first laptop, I did actually order Trackmate; and it arrived yesterday.Now that I've got LT2000 working,I think I'll just keep the Trackmate in its box until I find somewhere safer than the garage to keep the tracks.(And until the emotional scars have healed!).

David.

[Nor Cal Mike]

David, Thanks for the additional information. I will experiment with the settings as well.

[Stingray Racing]

[Stingray Racing]

Since we are reopening this thread on the new board I will post a pic of my new inline dead strip to help others. I used 1/4" brass for the dead sections leaving about a 1/16" gap between them. So far this works very well.

[Wolseley Hornet]

Looks very neat,Rocky.

[Nor Cal Mike]

Thanks for adding your pics and info Rocky. Yes, your set up looks really good. I have a question for you. You reported in the thread on the old site that your set up is counting well except for your Artin cars. Is that still the case? Have you tried to change the settings that David mentioned?

I didn't mention that I am using LT 2000. I am going to stick with it for now, at least until I get my system debugged. I need my system to count every lap by next year as I am scheduled to host a Group 5 proxy race that is getting started up. I have requested an October date next year so that gives me a year to make it work 100% or move on to Trackmate. I have one Trackmate system on my oval track but really don't want to purchase more Trackmate set ups to cover all of my tracks (I have three tracks). That is why I am interested in making this thing work.

For more general info, of the two designs being discussed here. Rocky chose the inline dead strip. David and I chose to do the split rail. My initial choice was the fact that the split rail has the added advantage of allowing power to the car all the way through the timing section. That is not a huge deal to me but I thought I'd give it a try anyway. Since then my attraction to the split rail is that I can experiment with different lengths of the secondary rail to see if I can find a combo that works. With the inline dead strip, you have under 1/2" of travel time when the car's braid contacts both segments to trigger your count and that is it. My secondary rail is 2" long so the braid is in contact with both segments for a full two inches of car travel. I also have the option to lengthen that distance if necessary since the open space between the two braided ends on my track are separated by 4". I can use all of that distance if I choose The split rails are more complicated to construct. The separation between the two segments of the timing circuit must fall exactly in the center of the pretty narrow braid of car. I calculated that distance to be 5/32". The two contacts must also be exactly the same height. That is why I decided to use the printed circuit board. I simply needed to scratch away a separation in the copper cladding and whala, I had a split rail. The hardest part is soldering wires to the copper surface it stays flat.

I haven't mentioned that RichD has put together a great article with all of the information summed up including pictures. He put in links to it in the old forum but I don't know if the links still work after the old site was frozen. I suggest that you contact Rich if you have problems accessing it.
Mike

[Stingray Racing]

Mike, because of the design of the guide on the Artin cars only the tip of the braid touches the track. If the braid is adjusted just right it will trip the lap counter. I still lose an occasional lap even with the very narrow gap in my dead strip. I plan to raise the front axle on my Artins to drop the guide lower on the track. With Artin cars the conventional two-sided dead strip may work better since the braid does not have to bridge a gap. We mainly race 1/24 cars so that is not a big issue for us. Race Coordinator does not have the same settings that David used with LT2000.

[RichD]

[Nor Cal Mike]

Thanks, Rich for posting those links. Your article is the meat and potatoes of this discussion. I got a little time to go out and play around with the timing system on my new track. I soldered the connections to see if it may have been the reason for my missed counts. I ran over a hundred laps without a missed count. However I did note about a 6 or 8 double counts in those 100 laps. I went into the control panel Of LT 2000 and increased the debounce setting and managed to go another hundred laps without a missed count or a double count. I thought I had the problems solved.

I had used a modified Carrera McLaren M20 that has a Slot.it guide and a Spirit pod and FK180 motor in it along with Slot.it axle and Paul Gage. The fact that it is pretty fast and very stable is why I chose it. Because uses the Slot.it guide, it is typical of the cars that I will be running on this track. I then switched over to my Racer Sideways Capri which is faster and more twitchy than the McLaren. I started by ensuring that the braid was fanned out by pushing forward against the weave of the braid. I again began having missed counts once again with this car. The only difference that I can see between the two cars is the increase in speed that the Slot.it boxer motor adds to the mix. I am currently running straight off of a 12v. car battery on this track so the speeds are high.
I may try cutting out another piece of the printed circuit board but I will increase the length of the outer counting segment. I have that segment set up at two inches right now. I could go up to as much as 3 1/2" in counting length if necessary. If that doesn't work, I might also consider moving the whole timing section to a slower portion of track. I have loafed around the track some while monitoring the counts and have found 100% accuracy at moderate speeds. There is a short 4 ft. long straight that comes after a moderate speed corner. It also has a braking zone at the end that goes into a hair pin so the speeds there are much slower. That might be the best spot.

All of my parts have arrived now so it is time to set up the permanent timing. I guess a couple of more days of testing will allow me to work out the bugs. I'll keep you posted.

[Nor Cal Mike]

I had another break through today in my home made split rail timing. I ran 100 laps with a revamped split rail with zero miscounts.

I ran all of these test laps using my Racer Capri which is currently the fastest car in my stable.

The key difference between this test and the last where I experienced occasional dropped counts is that I increased the length of the timing strip to 3". I had it set at 2" before. This is the first test where I had the power rail side hooked up to track power. This means that I now have power to the car all of the way through the timing section.

I also ran this test through my permanent interface. It is housed under the lid of a Carrera jewel case and is mounted on the track surface. I did this for ease of access as this track is designed to travel so easy connecting and disconnecting is important. I will dress the jewel cover up to look like a trackside structure of some sort.


Now it is time to build the finished split rails for the other two lanes and clean up the installation on the track surface.

Whoopie! This thing works and it works reliably! Thanks to all who put their inputs into making this successful.

[Wolseley Hornet]

Well done, Mike! :text-bravo:

Like the idea of putting the interface connection on top, disguised as a building.


:happy-cheerleaderkid: :happy-cheerleaderkid: :happy-cheerleadersmileygirl: :happy-cheerleadersmileyguy: :happy-cheerleadersmileyguy:


David.


(Aren't these smilies just the greatest thing?)

[Nor Cal Mike]

Well I have all three lanes hooked up and I have come to a problem. All three lanes count together regardless of which lane is triggered. Since I have bench tested it numerous times with no problems I can only assume that it is something else connected to the work I have done over the last two days. Besides hooking up all three lanes, I hooked up the one of the rails to the track power in each lane. I thought that maybe I might be getting bleed back through the power supply. On that theory, I disconnect the wires running through track power and tried again. I am still having random counts of multiple lanes whenever I trigger a count either by running over it with a car or by shorting across the split rails. I need to look at it through fresh eyes so I will get back to it again tomorrow.

Mike

[Nor Cal Mike]

I wired up a new very basic connector loom that runs from the computer to the interface box at the track. The cord between the computer to the box was suspect because I had rewired the ends of the DB25 connectors because the cord wouldn't work at all originally. This time I used short 3 ft. long wires and wired the track end directly into the track, eliminating the DB25 connection in the box. I tested the system by shorting across between the ground (wire to pin 25) to the counting wires (to pins 10. 11, & 12). Everything worked right so the new harness was good. I hooked it all up to the wiring connected to the split rail and still had counts crossing across lanes again. That is car in lane one would trigger both lanes one and two in the software. That seemed to isolate problem somewhere between the split rails and the connector box. Obviously there was some bleed through somewhere. I went through all of the wires, seeing no problems. I decided to scrape the grooves cut into the printed circuit board stock separating the two halves of the split rail. I wanted to make sure that there was a high degree of delineation between the two. After doing that I tested again and the entire system is working. Each lane counts individually now.

I did notice some double counts. It only does this at the highest speeds of my quickest cars. The software can be adjusted in the control panel by moving the "debounce" setting up or down. There is also a speed setting used to run the software on older, slower computers . If you set that to low with a fast computer, you will get missed counts. I know that from experience. I think I have it running correctly now but more test laps are needed to confirm. I can say that the system hits 100% at moderate car speeds so you can avoid this issue by mounting your split rail in a slower section of track such as a shorter straight.

I'll get some more pics later.

Mike