Turning a 10k Pot into a 100k Pot

Is it possible to multiply resistors to turn a 10k Pot into a 100k Pot.

Breakdown of what I'm trying to do: Got an RC car for my sister(she is handicapped) and its hard for her to hold the pistol transmitter, so what I was trying to do is remove the wires to the 100k Pots for acceleration and turning, and wire it into the two pots on a joystick. The only joysticks I've found have 2x 10k pots.

Is this possible? I know you can add resistors just wondering if you could multiply. (basically need the 10k pot to be 10x more)

Reply to
zigonick
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No. This can't be done passively. There are active methods, but they aren't trivial.

Depending upon how the pots are used, 10k pots might work.

If the pots are used as voltage dividers (one end to ground, one end to the positive supply, with the wiper voltage being used for control), then

10K pots will probably work just as well.

OTOH, if they are used as variable resistors (one end and the wiper, with the other end either unused or tied to the wiper), or if one end is driven from a high-impedance source, then using different values won't work (although it may be possible to modify other parts of the circuit).

Another option is to try to find 100K versions of the pots used in the joystick (assuming that it's feasible to replace them).

Reply to
Nobody

The game controller joysticks that I looked at (Nintendo clones) have

100K pots.

Granted, the joysticks are absolutely teeny, so if her handicap involves problems with fine motions they may not work without modification, but you can try.

--
http://www.wescottdesign.com
Reply to
Tim Wescott

Well I tried the 10K pot and it only allows full acceleration, From testing with just a nob 100k Pot Neutral is about at 49-50k, anything lower is acceleration and anything higher is reverse. growing as you get closer to

0, and 100k. So far the 10 year old joystick i have has a 10k pot, old Ps2 controller has 10k pot, Knock off Game Cube controller is 10k, no Y screwdriver to get into Brand Game cube controller or Wii nunchuck.
Reply to
zigonick

You might try a Maxim MAX545x dual variable resistor. It auto-resets to halfway and comes in a 100k variety. I think it uses a simple up/down adjustment so you might be able to build a pulse generator that is activated by the joystick. The product sheet is:

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Of course, it might be made from Unobtainium, but I think other vendors have similar products. Here's the full datasheet:

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Paul

Reply to
Paul E. Schoen

A) You used to be able to get joystick assemblies (and if you can't, then take them out of old enough joysticks intended for computers), so there might be wider variety if you look further.

B) The old ones, at least, used standard pots so one could remove the ones included in the joystick assemblies and put in a different value pot. Some mechanical work might be required.

C) Theoretically, one could take the resistance element out of the proper size pot and use it in the place of the resistance element in the too low value joystick. That may or may not be doable, it relies on finding a pot with the same physical size resistance element, and being able to properly take the joystick pot apart and replace it with the new element, and get it all back together.

D) Figure out the circuitry where the original pot is connected, and see if you can compensate for a different value potentiometer by changing something else in the circuit. Gameports in many computers used a timer, and one could compensate for the wrong value potentiometer by changing the associated timing capacitor.

E) Decades ago, various magazines ran articles on making your own joystick. They all offered up different methods, and if one is mechanically handy, one could make their own joystick using the pots of their choice.

F) Change your premise. Maybe two knobs would be suitable for her, place the pots in a suitable box spread enough apart and put nice big knobs on them.

Michael

Reply to
Michael Black

it's possible but not simple.

can you find suitable pots to modify the joystick?

can you modify the remote to work with 10K pots?

I once made a joystick by tying the shafts of two pots into a cross shape using paperclip wire. and mounting one on an L bracket and the handle on the other, (as I tied the pots first I had to cut slots in the handle and the bracket.

Reply to
Jasen Betts

Seems to me that two separate 100K linear slider pots might be easier to control than a joystick anyway. (Even for those of us who are not handicapped.)

Best regards,

Bob Masta DAQARTA v4.51 Data AcQuisition And Real-Time Analysis

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Scope, Spectrum, Spectrogram, Sound Level Meter FREE Signal Generator Science with your sound card!

Reply to
Bob Masta

Out of desperation, take the pot cover off and assuming it to be carbon, use a rotary tool with a cutter bit on it.. narrow the wiper width and keep measuring it until you hit your goal..

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Reply to
Jamie

Aha! Probably this is a variant of the old PC joystick interface, that 100k pot (and a range-setting resistor) charges a capacitor. If you substitute the 10k pot, and suitable range-setting resistor in series, you'll just need to change the capacitor from C to 10*C, and all will work normally. Look for NE556, or NE558, or other timer circuit running from the pot.

Reply to
whit3rd

First thing to try is just swapping it straight, and see if that works. Assuming that the pots are wired straight from power to ground, with the wiper being the output, the only difference will be slightly shorter battery life in the control unit.

Cheers

Phil Hobbs

Reply to
Phil Hobbs

Whoops, news client weirdness--the original post came up as new, and I didn't notice it was from 2009! I hope his sister had fun with her car, anyway. ;)

Cheers

Phil Hobbs

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Reply to
Phil Hobbs

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