A self-returning linear pot?

[Billfred]

I've been tinkering with some projects in my head, and while running the board at WUSC I figured out how to control one of them: a linear pot. But to make it better for the situation, it'd be awesome to have it return to the center automagically (or at least have a detent in the middle to let the operator know it's centered).

Does any such a device exist (cheaply)?

[Rick TYler]

I Googled on "potentiometer sliding" and found a bazillion hits. Here's a link to a manufacturer: http://www.ctscorp.com/components/Datasheets/442.pdf.

Have fun.

Edited to add: I found a number with center detents, but not self-returning. Have you considered a string pot with some sort of custom-made mechanical doohickey as the controller?

[Joe Ross]

Would a joystick work? They tend to have a somewhat linear motion and return to center automagically.

Here are two more pots with center detents: http://bourns.com/pdfs/PTA.pdf and http://bourns.com/pdfs/PTA.pdf

[Mike]

Originally Posted by Rick TYler

I Googled on "potentiometer sliding" and found a bazillion hits. Here's a link to a manufacturer: http://www.ctscorp.com/components/Datasheets/442.pdf.

Have fun.

Edited to add: I found a number with center detents, but not self-returning. Have you considered a string pot with some sort of custom-made mechanical doohickey as the controller?

No doohickey needed. Just attach a spring to it. Have the shaft of the potentiometer go through the windings of the spring. As you turn it, the spring will unwind and once you stop putting force on it it will snap back to place.

[Al Skierkiewicz]

Originally Posted by Billfred

I've been tinkering with some projects in my head, and while running the board at WUSC I figured out how to control one of them: a linear pot. But to make it better for the situation, it'd be awesome to have it return to the center automagically (or at least have a detent in the middle to let the operator know it's centered).

Does any such a device exist (cheaply)?

Bill,
What console are you working on? Lot's of companies make detented pots. Many people don't use them because it requires another pot in series that can calibrate the detent.
Modern digital consoles can have a programmed stop stored in memory that fixes all the problems with much less expense.

[Billfred]

Originally Posted by Al Skierkiewicz

Bill,
What console are you working on?

The IFI OI--the idea just happened to come to me while doing my show.

[Al Skierkiewicz]

No, what audio console do you do your show on?

[billbo911]

Originally Posted by Billfred

The IFI OI--the idea just happened to come to me while doing my show.

I think I follow what your trying to do. Make a control for some function that can attach to the OI by using a "self centering slider pot". Correct?
If so, a very cheap solution is to attach two springs of equal length, diameter, and wire size to the slider pulling in opposite directions. Make sure you stretch them equally and have enough travel on both to have the more relaxed spring still is in tension when the slider is at full travel. Now when you move the slider off center, the spring forces will pull the slider back to center when released.
Look inside a joystick, you will see a similar setup pulling the stick back to center.

[colin340]

you may want to try an airpot i found an ad in design news it looks real cool
www.airpot.com

[ECarlson]

Some sound and lighting boards have computer controlled presets where the board can return the pots (sliders) to any preset position. Is that the kind of board you are talking about?

I would guess that the pots have either a servo or stepper motor to return them to position. I don't know if the feedback mechanism is the pot itself (most likely, since the OI processing part of the boards are pretty much purely digital anyway), or yet another position sensor. It's also possible that the sliders are not pots at all in some of these boards, and are actually optical position sensors.