March, 2022 - Stewart Raceway

Quick SR3 Update

Sorry for not spamming you all for so long. I’ve been slammed with this SR3 project, among other things…

Anyway, yesterday I abandoned my hardware/software solution after not being able to fix one of the two problems I’m encountering with the use of Phidget cards for primary lap counting.

Instead, I installed a Trackmate SCL3 USB card for the primary lap counting gantry (finish line/lap trigger). I’m not a big fan of this card but it does the job and seems to detect my fastest cars both individually and simultaneously, where the 0/16/16 Phidget card clearly did not.

And, Race Coordinator (RC) also supports this card. Because SlotTrak doesn’t support the much more desirable Arduino cards, I’m using the 0/16/16 Phidget card to handle the pit-in gantry sensors (much slower car speeds there), and two Phidget 0/0/4 cards to handle individual lane power.

I’m going to do more testing today and will begin to prepare for a coming track day to really flush things out. I’m going to need five drivers and the fastest, noisiest cars we have to run things through the paces and make sure everything works properly with SlotTrak. I’ll configure and test RC once I have SlotTrak rock solid.

If you have T-Jets and/or L10 cars, please let me know. I’d like to test a few this coming week and maybe do a track day on SR3 next Saturday. T-Jets and most “pancake” cars are very noisy electrically, which can generate phantom laps if track circuitry is not adequately shielded.

Okay, shut-up and drive!

SR3 Construction Update: March 11, 2022

A generic Arduino Mega 2560 card works beautifully!

Well, I was on target to have SR3 ready to go last Sunday but unfortunately ran into an interesting technical issue. It’s a much longer story but essentially the timing hardware I decided to go with doesn’t detect faster cars due to SR3’s gantry position and the speed the cars are getting to as they pass under the lap sensors.

“Steve, just change hardware and open the damn track!” Easier said than done. The issue is dual gantry, six-lane tracks, require a timing card that can sense up to 12 lane sensors: six for counting laps and pit exits, and six for pit-entry. Not to mention two more 4-relay cards to handle individual lane power control.

This limits the number of options out there. I’ve been able to get everything to work with Race Coordinator using an Arduino Mega card but SlotTrak does not support Arduino cards and the prolific Trackmate SCL3 card can’t support six-lane dual gantry tracks.

So, I’m stuck with the Phidget 0/16/16 card, which SlotTrak supports but does not detect fast cars on SR3. Further, this card also does not detect two cars passing under the gantry sensors at the same time. Yea, big issues. I guess most tracks use Trackmate, Arduino, or do not employ dual gantries.

I’ve sorted out a solution to this problem courtesy of “Madman” Steve Medanic. Steve was an engineer and has built numerous slot car tracks. He ran into this problem on his last track build, which was only a three-lane track but quite a nice build and circuit.

Steve may not have seen the single-car detection issue I’m seeing because his lap timing gantry is only 18 inches from the final corner (SR3’s final corner is nearly six feet from the lap timing gantry). However, he did encounter the simultaneous car detection problem, which I duplicated on my track tonight.

Steve’s fix was building three “signal pulse delay” circuits to install between the gantry IR sensors and the Phidget card. These circuits basically keep each lane trigger signal active long enough for the Phidget card to register it. Problem solved!

SR3 has twice the lane count and will require six of these circuits instead of three. I’m thinking the pit-entry sensors won’t need this logic since the speeds going into the pits are way, way slower.

Another option for solving this would be to add a 1.5-in long piece of black tape to the back of each car. Not sure if everyone would go for that but it is way cheaper and quicker. And, just think…you could paint or otherwise detail the tape for concourse consideration!

Anyway, that’s the current situation. I’m trying to find a “canned”(integrated) time delay circuit that could be used instead of discrete components. There are plenty of cards out there for timed relay control that may work. If not, I’ll have to source the individual parts required to build six of these little devices and then wire them up and test them.

So, as I wait for parts–again, I’ll stay busy installing the crash barriers, display monitors, speakers, etc. No idea yet when I’ll complete this beast but not likely to start a new series for at least two more weeks.

SR3 Construction Update: March 3, 2022

Driver selectable lane voltage and individual lane power control for Yellow, Blue, and Orange lanes.

Finally making some good progress on SR3. Pretty much have completed all wiring, power control, timing system components, gantries, and all driver’s stations.

Today I actually connected SlotTrak and Race Coordinator to the track and, after some tweaking and configuration changes, everything worked!

I don’t have the track sections connected to each other yet but I tested the gantries and all the power control logic by hand and with a test car on one section. Both seemed to work as expected and nothing caught fire.

All that is left to do is connect all the track sections to each other, clean all the damn sawdust off the table and track, run some laps on each lane to make sure all the rails and sections are in good shape. Once that’s done, it’ll be time to install the crash barriers and get things ready for a track day to fully flush things out.

Before I get to the above, I’m going to lift the track to the ceiling and clean out the entire garage. Need to blow and vacuum the whole place out due to all the damn sawdust, wire insulation, tie-wrap debris, etc. Also need to get rid of a bunch of bikes and bike parts. This track takes up a bit more space and will force me to get rid of stuff that has been hanging on the walls or just laying around forever. I also need to wash my motorcycles before the sawdust becomes permanent.

Anyway, I’m getting close. Still haven’t chosen a new laptop for SR3 yet. I think I’ll flush it out with an old and slow one just to make sure the design works and all the components that are tied together with the one USB hub will work. USB is fast but having nine devices going through one PC USB port could present some problems, we’ll see.

The very cool thing about this hardware setup is that Race Coordinator and SlotTrak seem to work well with the hardware. I don’t have to flip any switches, reboot, or anything, just fire up the RMS and go. I’m digging that.

There is one technical hurdle to get over at some point. Right now, the driver can easily change the lane voltage to eight different presets, and any arbitrary setting. However, the software I currently have does not allow the Race Director to quickly switch the lane voltages back to a common track-wide setting. For now, I’ll have to connect to each lane, check the voltage, and set, if necessary the proper voltage for racing. I’m working on some code to make that process much quicker.

One other possible issue is that I’m testing Brad Bowman’s opinion that I could get away with just one power tap for the whole track. I actually installed three but two are powering the oval. The third connects to just about the middle of the road course, which means the whole 75-feet of road course only has two power taps. SR2 has eight!

So, when is SR3 going to be ready to go for a Track Day? I’m shooting for March 19 and maybe starting a new series on March 26. Stay tuned for the plan but it depends on whether or not we’ll need more power taps. We can always start the new series on SR2, if necessary.

SR3 Construction Update: March 1, 2022

Progress continues on Stewart Raceway III but it has been slowed by all those pesky things that seem more important at the time.

So, where are things? Well, the table and track roadway placement has been completed. The track power distribution system is complete and tested. While there are still technical hurdles to overcome, the goal of supporting different voltage levels for each lane–by the driver–has been achieved. It’s not completely ready, but drivers can select any voltage they’d like to run when testing or practicing. This means you can practice/test any car, at any voltage, at any time racing is not underway. Think about that…you no longer have to restrict yourself to 15v, 12v, 20v, or whatever. You can go to any open lane, set the “lane” voltage (at the driver station), and run your car.

This is significant and very important for maximizing track/testing time. You no longer have to find out what the track voltage is set at to decide what car you're going to run. You simply set the lane voltage to whatever you want.

Other than six lanes, and a much larger layout, SR3 is expected to support the same racing features that SR2 supports. One small difference will be a slight increase in pit spacing. SR3’s dual gantries will be spread slightly further apart to compensate for the higher pit entry speeds.

Lots of work remains but mostly tedious wiring, track section power connections, crash barriers, etc. After that, it’s all about software configuration and testing.

Power distribution under the main straight timing/pit gantries.

One huge difference between SR3 and SR2 is power taps. Brad Bowman insists that I can run just one power tap, at most two (SR2 has eight power taps). I’m not convinced just yet but I’ll start testing with just two to validate that. The track design of being able to convert sections and convert to an oval makes the usual power tap calculations more difficult. No biggy though, adding more power taps just costs more time and money.

So, SR3 is coming along nicely. My garage is a complete disaster but the new track is going to be quite cool. Yea, lots more work to do, but it’s getting close. Really only need to wire the gantries up and I can start testing things. The 6-lane, dual gantry setup adds some complexity and delay. I had planned to just use the usual RJ-45 twisted-pair cable to handle that but RJ-45 only provides 4-pair, which doesn’t quite handle a 6-lane dual gantry setup (need 6-pair x2). Yea, yea, I could make it work but decided to find some 6-pair cable to handle this. Sadly, it’ll take a week or so to arrive.

Then the challenge will be shielding the cable. Shielded 12-conductor cable is extremely expensive. In fact, way too expensive. Yes, some of the noisier cars can trigger false laps if the gantry wires are overly exposed to RF/EMI frequencies.

Can’t wait to get all the infrastructure completed and start running some laps on this beast.