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Dr_C

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Dr_C

293 posts

Hi Fatthinslim,

 

Nice work... but I am surprised you found it necessary to use such a high value of resistor... something  around the 150 ohms, 180 ohms or 220 ohms should remove the dynamic brakng without causing the cars to humm... if the cars are hummng then their motors are being powered in a lightly stalled state with one of the windings carrying a fair bit of current.

 

 

500 ohms will put the throttle signal very close to the drive away threshold... and for magless drivng may even be enough to prevent the cars from coming to a stop at all. Might be worth trying resistance values lower than 500 ohms...

 

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Dr_C

293 posts

With the Scalextric app the car needs to clear the exit sensor before the car is able to register a second lap. This is to avoid doublecountng of laps. The Magic app does not use this type of algorithm, instead it uses a programmed timng delay.

 

From what you describe either...

 

1/ the exit sensors are themselves faulty...(unlikely)

2/ where the harness plugs into the exit sensor board... might not be seated properly.

or

3/ the board can be fitted the wrong way around... in this case a car would need to clear exit on lane 2 before the next lap can be counted on lane 1.

 

I know of one example each of situations 2 and 3...

 

Either way probably best to contact Scalextric customer services...

 

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Dr_C

293 posts

The above sf thread is an interesting find thanks for sharing... I remember when a group of us were briefly trying to slow down magless SSD McLarens on an ARC PRO powered publc event... as we reduced the power the powerbase became unreliable before we got to the point where the cars could be driven with heavy fingers without excessive deslotting. I think this whole subject deserve further investigation and reporting of findings... are you up for sharing-back what you find in terms of reliability as supply voltage is reduced?

On the subject of current, the ARC PRO has internal resistors which monitor current and which are designed to provide voltage signals to trigger power shut down in current overload situations. Do these circuits still function correctly when reduced voltages are used? It would be good to have a definitive answer from experts on this point... so again your question is great...

 

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Dr_C

293 posts

Hi all, i havent tried the ARC PRO powerbase with any powersupplies other than standard 15V. I would recommend sticking with either one or two of standard supplies... then use the app to adjust power levels as advised in above post. For casual racing, brief use of the app to set power levels still makes sense... even if you are not planning to use the lap counting and more advanced race features.

 

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Dr_C

293 posts

Thanks Woodcote for bringing us back on track (literally!). I totally agree with your comment... that the ARC PRO powerbase and wireless controllers provide a truely amazing entry-level/mid-level slot-car system... very impressive and huge fun :)

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Dr_C

293 posts

@giovanni_russello

Dr_C I am a bit confused by your post: are you saying that dynamic brakes is the only option no matter whether the ARC PRO is used as stand alone or connected with the ARC/Magic App? So there is no way that we can have the behaviour where once the throttle is released the car coasts unless one presses the brake button? If the dynamic brake is backed in the controller firmware then I have an idea why this is the case.

 

Hi giovanni_russello,

 

Happy New Year and thanks for the question. So to clarify, the dynamic braking function is applied in the signal path before the data packets are sent over the BLE comms. These comms consist of a 6 bit throttle value, a bit for brake and a bit for lane change. The dynamic brake function is evident in these data packets. You are correct in challenging whether it is applied in the firmware in the hand throttles or whether it is applied in the powerbase at a point prior to communicating with the BLE device. Either way, neither the user nor any BLE app developer currently has control over whether dynamic braking is applied or not. I hope this helps...

 

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Dr_C

293 posts

Not sure about the repair ideas... they may add more problems... I would look for the underlying cause...

 

1/ Is the flipper absolutely free to pivot without resistance? (sometimes if the track has been bent the flipper becomes harder to move).

2/ Is the cover plate (which attaches with the four screw) by any chance distorted or bowed in shape? This could happen if the track has been bent and straightened or perhaps from heat damage.

3/ Is there anything else that is preventing the cover plate seating properly... from the photos it looks like the two pairs of wires from the solenoids may be sitting a bit proud?

4/ Are you screwing down the cover plate firmly - but without overtightenng?

 

Sorry if all of these suggestions are a bit too obvious... but solutions often are... once they have been found.... good luck!

 

C

 

Dr_C

293 posts

Hi gorp, I am a bit puzzled by your observations that a pace car (with fixed throttle setting) beats a skilled human driver who can speed up on straights and slow down (by just the right amount) for the corners...

I guess the situation you describe might apply to a very small oval track that is mainly curves... i.e. fastest lap speed is close to max cornering speed. It certainly would not apply to a larger circuit with long straights and a range of curves of different radii including R1 hairpins... this more advanced raceway configuration is my target...

Anyway, I am happy to respect that our opinions differ on this subject... and it is always good to listen, assess and learn from others :)

Thanks for encouraging me to contribute here.

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Dr_C

293 posts

Woodcote makes a great point... unless you fully and completely release the throttle, dynamc braking (which is standard on the ARC PRO) will have no effect... so it really should not be an issue. That said, I do like to see cars roll to a gradual halt on long straights... but not during races :)

 

And just to clarify dynamic braking is integral to the firmware in the wireless throttles so is enabled when the ARC PRO is operated stand-alone, with the official ARC APP and with the unofficial Magic app... both apps are great fun... so thanks to Scalextric for releasing their app and also for releasing the BLE comms protocol which enabled the independent creation of the Magic app... as I say... both apps are huge fun!!!

 

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Dr_C

293 posts

Hi gorp, thanks for that... it you could use throttle controllers in digital mode, you must have powered the challenger electronics from the motor output of a SSD decoder. I have done something slightly different, I have powered the challenger electronics via a simle bridge rectifier circuit with smoothing capacitor. I have then added a separate microcontroller to generate the car ID/LC strobe. This explains, perhaps, why I am not seeng the kinds of issues you reported.

 

https://www.slotforum.com/forums/index.php?showtopic=175130

 

The full project for anyone interested is on the sf forum... link below...

 

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