Turning a 10k Pot into a 100k Pot

Z

zigonick

Guest
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)
 
On Tue, 03 Mar 2009 06:54:49 -0600, zigonick wrote:

Is it possible to multiply resistors to turn a 10k Pot into a 100k Pot.
Click to expand...
No. This can't be done passively. There are active methods, but they
aren't trivial.

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.
Click to expand...
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).
 
On Tue, 03 Mar 2009 06:54:49 -0600, zigonick wrote:

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)
Click to expand...
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
 
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.
 
"zigonick" <zool_vamp@yahoo.com> wrote in message
news:86CdnWEtUe94NTDU4p2dnAA@giganews.com...
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.
Click to expand...
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:
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2568

Of course, it might be made from Unobtainium, but I think other vendors
have similar products. Here's the full datasheet:
http://datasheets.maxim-ic.com/en/ds/MAX5450-MAX5455.pdf

Paul
 
On Tue, 3 Mar 2009, zigonick wrote:

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)

A) You used to be able to get joystick assemblies (and if you can't, then
Click to expand...
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
 
On 2009-03-03, zigonick <zool_vamp@yahoo.com> wrote:
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)
Click to expand...
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.
 
On Tue, 03 Mar 2009 06:54:49 -0600, "zigonick"
<zool_vamp@yahoo.com> wrote:

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)
Click to expand...
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
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
FREE Signal Generator
Science with your sound card!
 
zigonick wrote:

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.
Click to expand...
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..

http://webpages.charter.net/jamie_5"
 
On Mar 3, 2:02 pm, "zigonick" <zool_v...@yahoo.com> wrote:
Well I tried the 10K pot and it only allows full acceleration,
Click to expand...
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.
 
On 3/3/2009 7:54 AM, zigonick wrote:
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)
Click to expand...

<not an RC guy warning>

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.

</not an RC guy warning>

Cheers

Phil Hobbs
 
On 2/21/2014 9:23 AM, Phil Hobbs wrote:
On 3/3/2009 7:54 AM, zigonick wrote:
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)



not an RC guy warning

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.

/not an RC guy warning
Click to expand...

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


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net
 
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