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.
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.
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.
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.
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.
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.
Finally able to get back to work on the new track this week. Not a lot of progress but I was able to wire up one driver’s station and test the individual lane voltage control hardware.
The initial hardware will support two preset voltage selections and a variable voltage setting. The track will be fed by two 30VDC, 10-amp, regulated power supplies: one for lanes 1, 2, and 3; the other on the opposite side of the track supplying power to lanes 4, 5, and 6.
