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Dr_C

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Dr_C

293 posts

Many thanks blagard-01... diagram is perfect!

Hopefully top down photo attached below... underside wiring photo to follow...

Dr_C

293 posts

Hi Josef,

i believe you are misunderstanding where the short circuit is likely to occur. The flipper is not relevant all all. The short circuit will occur on the rail next to the flipper precisely where you put the cut. Your cut is I am sure intended to separate two track signals which are pulling in opposite directions I.e. the full 15V switched signal will be present across the cut line at all times. When the car brush passes over the cut the two sides of the cut line will be ‘bridged’ i.e. a full current serious short circuit. If you don’t believe me, move the car very slowly by hand (no throttle power) across the cut line and watch the ARC PRO go into SAFE mode. You are stressing the system every time you drive over the single cut line. Really not a good idea!

If you are planning two cuts, 10-15mm apart that would be fine - but that’s not what you are showing in the photos, hence my concern.

C

Dr_C

293 posts

Hi all, this modification is moving along the right lines (in my opinion), BUT still absolutely not recommended (in my opinion). This is because at the point of the cut, there will be opposite signal polarities on each side of the cut line. This configuration will result in a short circuit occuring briefly each time a car’s pick-up brush traverses the cut line. Given the power base can provide approv 8 amps of current, this will generate quite a sizeable spark each time. This will be bad for at least two, possibly three, reasons.

1/ it may affect nearby rf comms (sparks are broadband rf noise)

2/ the short circuit which occurs every time will be trying to put the ARC PRO into safe mode albeit briefly each time. This may cause long term damage, or premature failure, of the ARC PRO drive circuits) and worst case senario some blue smoke...

From a design piont of view I would strongly advise against this configuration... albeit that it appears on the surface to work in a satisfactory way in the short term.

If you don’t believe me - briefly try driving cars (with no lights) over the cut line in a darkened room - and watch out for the sparks... the sparks will be generated by 8 amps current at 15 volts...!

C

 

 

 

Dr_C

293 posts

Thanks Blagard-01 for helping with a further diagram image.. I very much appreciate this kind help...

C

Dr_C

293 posts

Hi all, yes, this option C will be fine for up to the maximum number of cars i.e. 6.

This is not a problem because inside the ARC PRO the exact same drive circuit powers both lanes anyway (it’s just that the signal polarities have reversed for other reasons). For 4 or more cars you need two standard PSUs to be plugged in (as per Scalextric instructions).

Just to clarify a point of detail, way back when I first proposed option C, what I had in mind was exactly as per Blagard-01’s above diagram. However more recently I have been proposing an alternative way to implement Option C to achieve an identical ’electrical‘ effect - by simply cross wiring the rails of a single lane at the point where the dead spot is formed. I show this as the point marked X in my earier rough ‘tty‘ diagrams. This keeps the modification effort to one lane only. I know an updated diagram is required to add further clarity and I hope to share this tomorrow along with some nice photos the little red mini in action on curved lane changers!

I hope this helps...

C

Dr_C

293 posts

Above post while slightly ‘of topic’ does contain an interesting metaphor which, for me, brings two important thoughts to mind...

1/ does the sight impaired squirrel find the nuts because it uses all of its other sensory inputs working collectively to help pin point the food?

2/ or does the squirrel live within a ‘caring community‘ which helps ensure those squirrels which have difficulties finding food are supported?

Sorry if this off topic - but it ‘kind-of‘ follows on from the wider scope and perspective introduced in the previous post.

Dr_C

293 posts

Now finished a couple of alternative versions of the curved lane changer approach... each version uses the 10mm dead spots mentioned earlier. Still testing...

1/ similar to blagard-01’s excellent ‘double dead spots‘ approach but modified using the rail ‘remove-cut-and-replace’ technique described earlier in this thread.

2/ introduction of a single 10mm dead spot alongside the output flipper (wedge) - but this can only be used for variants where this wedge is fixed in position (otherwise shorts would result).

Time taken to modify two curved lane changers was a total of approx 1 hr i.e 1/2 hr per changer using dremmel, hand file, 5 mins epoxy and attachment of one jumper wire.

Photos and diagrams to follow - slightly delayed because I want to compare and contrast the two alternative versions... :-)

Dr_C

293 posts

No worries... it’s likely to be Monday before I upload more photos of my track based trials...

Dr_C

293 posts

Thanks both - yes been a bit busy on several fronts... just learned how to post photos (great progress for a newbie like me). I’ll put up another photo and then another diagram (big thanks blagard-01 for helping with this) and then ...  (hopefully) that will be option C fully covered. My 1/4 length modified track parts are now ready for endurance testing over the festive season!!! Thanks to those who have formed a critical review panel for this option... I know it has absorbed quite a bit of your time - thank you!

And, just added jumpers to implement Options B and C using a soldering iron but without risk of melting the plastic track (idea copied directly from Scalextric actually so not new at all) ... more of a simple and hopefully useful tip... :-)

Dr_C

293 posts

No worries - and meanwhile I appreciate the good sense of humour, and good sense of irony, brought together in typing the post directly above this one.

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