# Need help at making a homemade flight joystick

#### Sinnlichkeit

Joined Nov 8, 2020
3
Hello.
I'm making a homemade flight joystick. It's a full metal cockpit, very realistic, but I'm having a problem with the joystick itself.
The movement of the stick is very short, and the potentiometers have a very long travel compared to it.
The interface has 5v and I'm using 5k ohms potentiometers. My question is: Is there any way I can shorten the potentiometer's travel?
A way to fix this problem is by using gears (a big one in the stick with a small one in the potentiometer), but it would be difficult to get gears in my town.
Another solution I was thinking about is by putting 10k ohms potentiometers instead, so with half travel it might give 5v, would it work? I'm begginer at this so can someone to confirm this?

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#### MrChips

Joined Oct 2, 2009
24,232
You could rotate the body of the potentiometer so that the variable resistance begins at the lowest value, i.e. 0 ohms.
Hence you will be using a fraction (say 25%) of the pots fullscale range.

#### Sinnlichkeit

Joined Nov 8, 2020
3
You could rotate the body of the potentiometer so that the variable resistance begins at the lowest value, i.e. 0 ohms.
Hence you will be using a fraction (say 25%) of the pots fullscale range.
Your solution works with the throttle, that goes from 0% to 100%
But in other axis it needs to be in the middle, because i.e. in the elevator, it goes from 0k to 2.5k Ohms down and from 2.5k to 5k Ohms up, while 2.5k (50%) is centered, so if I rotate the potentiometer to another value it wouldn't be centered

#### MrChips

Joined Oct 2, 2009
24,232
Another solution is to use an op-amp to subtract any amount of DC offset and then amplify the signal, or the other way around, amplify the signal and subtract an offset.

#### MisterBill2

Joined Jan 23, 2018
9,294
A simple mechanical option would be to use linear instead of rotary controls.
I am guessing that the intention is to have 2.5 volts out with the stick in a neutral position, and go to zero at one extreme and 5 volts at the other extreme.
Another way to get that will be to use two photo-resistors in series across the 5 volts and moving the stick shades one or the other. That can be simple mechanically and it will not wear out. And it can be made very sensitive. But the challenge will be to get photo-resistors, not photocells or photo-transistors or diodes. Something like the Clairex CL2 is one choice.

#### Sinnlichkeit

Joined Nov 8, 2020
3
I solved the problem.
Just downloaded a software that establishes the potentiometer's range limit to your choice, also its nonlineanirity, multiplier and corrections.