43 replies to this topic

[mtpanorama]

Anyone else tried this, converted a Parma Econo controller to diodes.

A bit of Vero board cut to size, Araldite on a bit of small conduit to fit on the existing bolt, soldered on some diodes and a little bit of adjustment on the bracket to make sure everything runs smoothly and doesn't touch where it shouldn't.

[slotbaker]

Sort of..




I used brass and fiber washers over plastic tube.

It worked OK, except that I could have used thinner fiber washers.

[kalbfellp]

I have converted an old Slotworks controller with 3 more diodes BUT still only using 6 bands, works well and have added some switches to switch out 4 diodes when less control needed. IMO you need 12 to 16 doides to get good control. I also had another home built using stud mount diodes set up like an external resistor down on the panel,it was great for Group cars.

[dangermouse]

I have 2 Parma controllers now - I need to buy a 3rd controller for the 3 lane track -
What is the advantage of a Diode controller over a standard controller?

cheers
DM

[mtpanorama]

I managed to get 11 diodes in this one, left 2 strips on either end for brakes and max power, might have been able to squeeze in another 2 but then risked not hitting full power and/or having the button short the brakes to the power.

Works well with 16D's and other high power motors on my track but is a bit much with Scaly, Ninco etc but then I have a MRRC power supply per lane and I think these put out more then the stated 12 volts, multi-meter needs batteries. I'm going to try it out on a couple of other tracks to see how it goes but was thinking I might need more diodes, might double some up like slotbaker's and make them switchable like Phil's. Thanks for the ideas guys.

DM, if you already have 2 Parmas and are happy with them I would stick with one of them for a 3rd controller just to keep everything the same.

Don't know about the advantages of a diode controller, I was reading something about the PM diode controllers and seeing as I had made a slow down switch using diodes I thought why couldn't I use this to control the speed in a hand controller.

[kalbfellp]

The voltage drop across each contact band is more linear than a resistor.

[stoo23]

Hmm,..Not so sure the Word 'Linear' is what I would have chosen to Describe Exactly, the effect of Diodes Over a Resistor.

A Wire Wound Resistor, provides the Drop in Voltage due to a change in Impedence over it's Range.

Diodes Always Give the Same Voltage drop,...2 to .3 of a Volt, so in Reality, you have a Little Ladder,..with 'Steps,..Unlike the theoretical 'Linearity' of a Resistor. Thus describing why Diodes are Often used for Brake adjusters, as Each Step Is predictable.

The Real Point is though,..Linearity of the Controllers Wiper band is Not really an Issue,..Or perhaps even what you want.
Under Load, the Output or Slope of Power,..is Not Linear.

In Reality, one would Ideally like to Have 'Linear POWER' on the Output and there are Very FEW Controllers that actually accomplish this,..Perhaps Maybe Dan Ruddock's controllers come to Mind.

Perhaps the ACD and or 3rd Eye may also accomplish Linear Power,..Few Do.

One could reasonably argue, that the 'Plot' of the Output of the controller Would and Should be quite different, driving an Open 'Wing' car on a Blue King,..as say compared to a 1/32 scale car around a Home style track.

Edited by stoo23, 11 March 2009 - 02:20 PM.

[rick1776]

Diode controllers are all wrong, but hey if it works for you go with it.

http://people.seas.harvard.edu/~jones/es15...cteristics.html

The response of a diode is exponential, if you want linear power then the response should be logarithmic. Thats why most diode controllers I have used are really quite dead through the bottom bands and it comes on gang busters in the last couple of bands. If that suits your driving style then a diode controller is for you.

[imugford]

i was waiting for the techniqual response from rick

[kalbfellp]

Diode controllers them selves are more linear than resistor controllers simply because each step gives almost a constant voltage drop. Yes diodes are not in them selves true linear devices. But not controller I have seen yet will suit all motors and cars without some sort of adjustment. So you end up spending a lot of time adjusting the controller for different cars and less time driving. The best idea is to just try as many controllers that you can borrow and then pick the one YOU like best. every person is different.

Edited by kalbfellp, 12 March 2009 - 07:16 PM.

[chilla]

I reckon if we can convince Rick Field to do an analogue version of the Scorpius wireless system (ie chip the lane rather than the car), the future is with his mammoth take on Aussie Ingenuity, even within the hallowed halls of analogue heaven...(youse blokes use brake, doncha? ...don't remember seeing them in the sixties... )

[The Stig]

Quote

don't remember seeing them in the sixties

That was probably because of what you were smoking! I have an old MRRC barell controller and it has brakes. I have also seen an article from the sixties on how to add a 9v battery for reverse voltage brakes!

[chilla]

The Stig, on Mar 12 2009, 10:12 PM, said:

Quote

don't remember seeing them in the sixties

That was probably because of what you were smoking! I have an old MRRC barell controller and it has brakes. I have also seen an article from the sixties on how to add a 9v battery for reverse voltage brakes!

(Clarkson) Some say that the Stig evolved from the depths of toy car racing but we beg to differ...

(Hammond) Hats off, my man...

(May) Love to see the battery-assisted article...

[aussieslotter]

chilla, on Mar 12 2009, 08:57 PM, said:

I reckon if we can convince Rick Field to do an analogue version of the Scorpius wireless system (ie chip the lane rather than the car), the future is with his mammoth take on Aussie Ingenuity, even within the hallowed halls of analogue heaven...(youse blokes use brake, doncha? ...don't remember seeing them in the sixties... )

That would still be digital.(Well half digital!) But the car would still be analogue.
But we could make a 256 step digital controller with analogue output based on what we have with LCD screen and trim pots, traction control, throttle curve with thousands of possible combinations etc. Quite a few analogue die hards in Europe said it had the most control of any controller they have ever tried.

Edited.

Edited by aussieslotter, 13 March 2009 - 05:08 AM.

[chilla]

aussieslotter, on Mar 12 2009, 11:33 PM, said:

chilla, on Mar 12 2009, 08:57 PM, said:

I reckon if we can convince Rick Field to do an analogue version of the Scorpius wireless system (ie chip the lane rather than the car), the future is with his mammoth take on Aussie Ingenuity, even within the hallowed halls of analogue heaven...(youse blokes use brake, doncha? ...don't remember seeing them in the sixties... )

That would still be digital.
But we could make a 256 step digital controller with analogue output based on what we have with LCD screen and trim pots, traction control, throttle curve with thousands of possible combinations etc. Quite a few analogue die hards in Europe said it had the most control of any controller they have ever tried.

Ah, yes, digital but not with the scary lane-changing bits.

I'd suggest that there's, initially, a bigger market for a beautifully sorted wireless racing handle to suit the old-fasioned roundy-roundy racers than there is for the proper, grown up lane changing upstarts.

Yep, digital-with-lane-changing is the future but why not get a shirt-load of mega-bucks off of the old farts as well?

[slotbaker]

chilla, on Mar 13 2009, 01:09 AM, said:

................ but why not get a shirt-load of mega-bucks off of the old farts as well?

Good luck with that.

[mtpanorama]

Just what I thought, my MRRC transformers are giving me 17 volts unloaded and 18-20 volts with a car running on the track so even with 11 diodes the start voltage is over 10 volts which would explain why Scalextric, Ninco etc were almost flat out on the first band.

Tried it on another track today running at 12 volts and it was better but still coming on a bit hard for some cars so a couple more diodes could be the go.

[rick1776]

17 volts unloaded and voltage goes up when power supply is loaded??

[mtpanorama]

I thought it was strange too, brand new batteries in the multi meter. Hoping someone knows something about these MRRC power supplies.

[The Stig]

I have seen this happen! Seems that some cars and OR meters seem to give incorrect readings when the cars are running,just try another car when you test. The best way to test is using a propper load.I have an old carbon load unit from an old auto test bench and that works great.

Phils diode controller has 15 diodes and seems fine to me,but he has now added some switches.