# Controller build help please



## Xence (Oct 2, 2007)

After looking through a controller I recently received from mking I started thinking it through about how to build a controller. At first I tried to reverse engineer what I had bought from mking and afterwhile figured out that I didn't need to do that. What I needed to do was to figure out what resistor/potentiometer resistances were needed for both the regular driving pot. and what size the fine tune pot. would need to be. 

Near as I can figure for the fine tune pot. you need approx., and I could definitely be off here, 300-500 ohm pot. The regular driving pot would need to be, and I'm just basing my thoughts off of the original A/FX cars, approx. 60 ohms. Of course these 2 pots would need to be wired in parallel.

Am I on the right track here? Am I way off? Is there any interest in doing this or am I one of the only ones?

Cheers,
Xence


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## Wildstar (Jan 8, 2008)

What kind of controller? Resistor or electronic?


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## Xence (Oct 2, 2007)

resistor = potentiometer.

Various potentiometers, or variable resistors if you'd like, will put out various amounts of resistance (ohms).

I'm honestly not trying to be a wiseguy. I have no idea how much people do or don't know about electronics.

Cheers,
Xence


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## AfxToo (Aug 29, 2003)

Xence, check out Steve's Siberia Racing website. He has some great articles that cover exactly what you're talking about, along with a ton of other great articles.

http://home.comcast.net/~medanic/Tech-1.htm


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## Wildstar (Jan 8, 2008)

Xence said:


> resistor = potentiometer.
> 
> Various potentiometers, or variable resistors if you'd like, will put out various amounts of resistance (ohms).
> 
> ...


No worries Xence. I didn't understand whether you were trying to add adjustability to traditional controller, or if you were messing around with the sensitivity pot on an electronic unit.

The Siberia racing page that AFXToo mentioned is pure gold. I've been toying with the idea of adding a dial-down sensitivity pot (see Steve's figure 2a) to one of my controllers. If you're running A/FX and Magnatractions, then it seems like a good starting point would be a 90 ohm main resistor, along with R1=0-500 ohms and R2=100 ohms. That would give you a range of 42-78 ohms overall resistance, while still being reasonably linear.

By all means, keep us updated on your progress. Best of luck!

What about the mking controller? Does it follow one of the schematics on the Siberia page, or is it something different?


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## Xence (Oct 2, 2007)

HEY dangit.... I totally missed my own stupid thread.... LOL. Color me an idiot. 

Wildstar what you are proposing is EXACTLY what I was planning on doing with one minor variation. I was going to try what you're talking about but I was going to do it with a 60ohm. Last I checked, and correct me if I'm wrong but it was R1*R2 and divide that by R1+R2 which gives you your total. I think. Now that we're dealing with variable resistances though things change all depending (obviously) on where each potentiometer is set.

I'm glad I'm not the only that's trying this. After reading what you guys are saying there is an electronics shop just up the road that I need to go and pick up a few different pots to try various things out. 

I went to Bob Beers' Long Island show and one guy had a REAL nice controller but he also wanted $200 for it. He did a bang up job to be sure, don't ask me who because I can't remember who he was, and he was pretty helpful concerning all of the questions I was asking him.

The mking controller that I got was a prototype made by someone else, I forget who, hopefully he'll chime in on this and say who it was. That's an resistor/potentiometer deal, real nice and EXTREMELY smooth. That is sort of what I was aiming towards in this controller I'm trying to build now. Not sure how successful or unsuccessful I'll be. I post things like this hoping that people like you and AFXToo will respond.

of course I'll keep you posted. 

Thanks for your help gents.

Cheers,
Xence


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