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Hi Guys,
Phil posted recently about motor parity for races. Its often bugged me too especially if supplying all cars. On a 6 hr we tested cars prior and adjusted the speed limiter so all lap times were within 0.1 sec.
Its time consuming and it affects fuel burn rate parity.

So what to do?

Another feature of the Gen II Scorpius chip which I havent mentioned yet is the ability to sense current.
Ive just spoken to John and between the current sensor, back EMF and hall sensor it is possible to have
a new feature Ill call Auto Parity.
Not sure how much firmware development will be required but the hardware is already in place.
Interesting times ahead 😊

Rick
 

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Hi Guys,
Its time consuming and it affects fuel burn rate parity.
Rick
Very time consuming, if I wasn't on holidays I don't think I could have done it, that said time driving slot cars with a purpose is always fun .

Auto Parity sounds very interesting indeed
 

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I don't think current sensing will get the cars equal unless I don't understand how it works. It can still be the same current for different motor setup, gear or tyres I would think?

Car rotation is by far the best option :)
 

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Hi Minardi,
Thanks for chiming in. Car rotation is an option. But that isnt going to happen where everyone brings their own cars, or enduros or serious competitions where everyone buys and builds their own cars.

So there must be a solution. But only if you have the necessary hardware.

It wont be by current sensing alone but a combination of current sensing, rev sensing and back EMF sensing.
Model trains do something similar now where they even out the output where two or more locos are used together to pull the carriages.

Plus if John says it can be done it will be done.
Just how it will work Im not quite sure of yet. We have the smart hardware in place its just a matter of firmware.
Its going to be exciting over the next 5 years. And were still at the beginning.

Rick
 

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Discussion Starter · #5 ·
Im thinking too the wheel diameter might have to put into an algorithm and configured to the car as this is a variable as well as number of teeth on pinion and crown.
I cant think of any other variables at this stage.
 

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Bob Chapman
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Would roll out answer the question to your last part regarding wheel dia. and pinion and crown or spur count.
Just a thought that popped into my head.
Bob
 

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Discussion Starter · #7 ·
Hi Chappy,
I think I might know what you mean?
Do you mean getting the entire car rolling the tyre along some paper, measuring the distance and counting the motor turns and working out the distance, divide it to come up with an overall answer?
 

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Bob Chapman
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Yes that is what I was refering toSome would do it by measuring the distance by one revolution of the motor, however I was thinking about one revolution of the tire .
Does that make any sense.
Bob
 

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Sounds good Bob. I could have either option in the config program.
Another variable I thought of is tyre expansion as the car reaches higher speeds..I might leave that out as all cars would have a similar value and it would be too difficult to get correct.

I could use the the cars tacho and telemetry to count how many motor revs while the car is in the track and measure the roll out say along a straight part of the track.
Or I could use this: The distance between 2 l ok Lane Brain is known example 163 cm. This value is fed into the configure program and stored as default unless changed. The car is placed at the first Lane Brain and driven. As soon as car passes lhs second Lane Brain the program automatically calculates the result using motor tacho results.....say for arguments sake 37. The program divides 163 by 37 to give the answer. Tap car x amount of times to put car into Auto Parity mode, press button on config program and the car accepts the new throttle curve. Bingo Auto Parity.

I could use the same procedure with car at full speed to take into account tyre expansion. I could even just do an entire lap as the longer the distance the more accurate it would be.
Next problem how to make a program to adjust throttle curve or I could just keep doing laps and maximum throttle is reduced a fraction lap automatically until the car comes into a parity lap time.

Rick
 

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Bob Chapman
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Wow now you've lost me.
But if a mind can do it I'm sure the electroincs can do it faster.
Bob
 

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Discussion Starter · #11 ·
Sorry mate😊
Sometimes even I get lost 😊

Rick
 

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Discussion Starter · #12 ·
Basically take the car do a few laps and rollout motor revolution telemetry are sent to PC.

A rev limiter is employed so all the cars have the same revs.

Because different cars will have different gear ratios, wheel diameters and tyre distortion due to centrifugal force the rollout data is used to compensate.
Should be ok and not a difficult project.

Rick
 

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Rick,

I have a question or two...and maybe this does not pertain to "parity"...

Will this compensate and change for how a car runs on the track?

Lets say you have a new fresh car, motor not broke in, fresh tires bushings, etc..

I have a well broke in car, fine tuned...will this "parity " program hinder one car or the other, almost de-tune if you will??

I am not sure I am explaining correctly, or understanding correctly, I seem to have the impression that is kind of make all the cars run the same, or as close as possible through an electronics program? Maybe I am way off??....its -18*C here, so my brain could be starting to freeze up...

Thanks,

Shad
 

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Hi Shad
Thanks for your question. I get what your saying.
Im looking at how digital train systems do it with multiple locos. Back EMF detection seems to be the main tool.
That will make it even more accurate.

And then we have resistance, another issue. The longer the car runs the hotter it gets the more resistance the slower it goes.

We had positive 48 degrees Celsius here a few days back maybe my brains fried 😂

Rick
 

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Bob Chapman
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That was essier to understand . Thanks
Bob
 

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As a non-techie I can add to this my own personal observation.

last night we had a race with 4 scalextric Audi's and one SCX Aston. The SCX car was quite competitive where it came to speed, laptimes - quite even I'd say. But its fuel consumption was remarkably higher, the SCX car had to pit first with an empty tank while the scalextrics were still zooming around with about 30% fuel left.
swapping the car between racers to get the human trigger finger factor out gave the same result. SCX cars use more juice :)
 
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