Potentiometers!!!!

[manhattan]

Hi.

I am building a yoke system for my 'Otter', and need to know whether or not I need a gearbox for the potentiometers? I notice that they have a heck of a 'sweep', but see that some people use them as they are without any gearing. I have not done any experiments yet, but some advice would be appreciated.

Thanks all.

TONY.
Plymouth UK

[spitfire9]

Lea Bodnar in England ,sells 3 or 10 turn potentiometers.

[Tripacer]

I used a small gear train on my pitch yoke to increase the movement of the pot. The control yoke had about 20 degrees and 4 to 1 gearing gave me a larger movement range on the pot. Remember that the hardware interface is trying to digitize the changes in voltage and the greater the range the better the resolution bits you will have. If the interface provides 1024 bits of resolution over the entire pot range and you can only get a quarter turn then you only have about 256 bits of difference.

Tripacer

[manhattan]

Thanks.

Not sure what a 3 turn or 10 turn potentiometer is? It sounds obvious, but can you explain?

Cheers.

TONY

[IanH1960]

Thanks.

Not sure what a 3 turn or 10 turn potentiometer is? It sounds obvious, but can you explain?

Cheers.

TONY

Hi Tony,

It's the number of shaft rotations that make up the full electrical range of the pot. eg with the 3 turn it takes 3 full shaft rotations to move the "wiper" from zero to full resistance.

Quite handy if you are fitting them to a shaft that makes multiple rotations, however not so good if your shaft only makes 1/2 a turn or so...

Ian

[verticallimit]

I have just modified an MD80 throttle for USB 2.0
I used 10 turn potientometer that only rotate 5 times form 0 to 100%.
I thought that this would be a problem. but after having calibrated the axis in the computers control panel, it works extremely well from 0 to 100%.
The axis enters leobodnar (http://www.leobodnar.com/products/BU0836X/) joysticks card

http://www.md80project.dk (http://www.md80project.dk)

[manhattan]

Hi

"computers control panel"? would this be under "game controllers"? Does this allow you to increase (electronically) the effective rotation of the pot shaft so that a yoke movement can look as though it is producing a larger wiper movement? Sorry to seem dim - can you explain in more detail?

Thanks.

TONY

[verticallimit]

Hi Tony

Yes, it is in game controllers, you can calibrate the position of 0% and 100% scale of the axis, then windows creates a straight path from 0 to 100%, this curve can not be adjusted or bended.
But if you have a potentometer only using 50% of its revolution, then you can get Windows to correct and change the input from 0 to -50% to 0-100%.
But in fsuipc you can change your axis to more or less steep curve from your zero point.

[manhattan]

Hi Tony

Yes, it is in game controllers, you can calibrate the position of 0% and 100% scale of the axis, then windows creates a straight path from 0 to 100%, this curve can not be adjusted or bended.
But if you have a potentometer only using 50% of its revolution, then you can get Windows to correct and change the input from 0 to -50% to 0-100%.
But in fsuipc you can change your axis to more or less steep curve from your zero point.

Hi Claus.
Thanks for the tech info. I take it then that a normal potentiometer (rotary or slide) without any gearing, can be treated in this way to simulate full wiper movement? Sorry to keep coming back to you on this.

Grateful thanks,

TONY.

[verticallimit]

Hi Tony
That's fine, just ask away.
I rebuilt my throttle, and only used the half of the rotation of my 10 turn potentiometer I thought initially that I would get a less sensitive axis, but when I have calibrated the axis in "game controllers" the work area have a full scale from 0 to 100%

I've made a drawing that would show what happens.

We have a potentiometer with work area 20 to 85%
The output til FSUIPC will be 20 to 85%, if not calibrated

http://img535.imageshack.us/img535/2328/joykalib.jpg

After calibration, the working area will give full scale 0 to 100% to FSUIPC

I have no problems with only using 50% of the axis of rotation, my trottle is very sensitive and works very well.