How to adjust a rotary potentiometer via the arduino software

Hello,
I want to build a midi controller that connects to my PC and controls the parameters of an EQ plugin in my Digital Audio Workstation (meaning my software to make music, basically). Since I will be using different instances of this EQ that would all have different adjusted parameters, I would like to create an arduino system that is able to adjust its rotary potentiometers according to the values of the current instance of my EQ. Does anybody know which hardware I could use to realize this, more specifically if there are potentiometers that have a built in motor or so, that could do this?

Thanks for your help,
Jannes D

How much space is available to attach a motor, gears and limit switches to the potentiometer shaft and mounting nut.?

Paul

jannesd:
Does anybody know which hardware I could use to realize this, more specifically if there are potentiometers that have a built in motor or so, that could do this?

Have you considered digital potentiometers?

Paul_KD7HB:
How much space is available to attach a motor, gears and limit switches to the potentiometer shaft and mounting nut.?

Paul

I could vary the height of my midi controller depending on the space that is needed to realize this feature. I was planning to build a case with dimensions of something around 30cm x 20cm x 10cm, but as I said, it's really not set in stone.

Look into using the motor and planetary gears from an electric screwdriver. You still have the problem of mounting two limit switches.

Paul

johndg:
Have you considered digital potentiometers?

What are those exactly? :smiley: I'm pretty new to working with an arduino and I don't know many of the components and possibilities available. I would need a phsyical knob though.

Paul_KD7HB:
Look into using the motor and planetary gears from an electric screwdriver. You still have the problem of mounting two limit switches.

Paul

Can you explain that further? I'm really new to all this, and all of that answer means nothing to me :smiley: sorry. Does that solution imply to take apart a screwdriver? Because I would need about 16 of these knobs and I wouldn't wanna take apart 16 screwdrivers for this project. Again, really sorry if I'm not understanding correctly.

What I want looks something like the adjusting faders in this youtube video at 3:30, but mine would be with knobs:

jannesd:
Can you explain that further? I'm really new to all this, and all of that answer means nothing to me :smiley: sorry. Does that solution imply to take apart a screwdriver? Because I would need about 16 of these knobs and I wouldn't wanna take apart 16 screwdrivers for this project. Again, really sorry if I'm not understanding correctly.

What I want looks something like the adjusting faders in this youtube video at 3:30, but mine would be with knobs:
https://www.youtube.com/watch?v=Ee40diuWijc

That is exactly what I mean. Plus you will have to fabricate the mounting mechanism and the limit switch mechanism and the wiring, of course.
Perhaps you are beginning to understand why there are no commercially available devices to do what you are proposing.
Paul

jannesd:
What are those exactly?

See , for example.

jannesd:
I would need a phsyical knob though.

Why? I thought you were boxing everything in, with motors turning the knobs.

Paul_KD7HB:
That is exactly what I mean. Plus you will have to fabricate the mounting mechanism and the limit switch mechanism and the wiring, of course.
Perhaps you are beginning to understand why there are no commercially available devices to do what you are proposing.
Paul

Well if it can be done with faders, why can't it be done with knobs? I don't think the mechanism behind it would be that hard to realize, if you have the means to do so. A servo attached beneath the potentiometer that simply moves along with the knobs when turning them by hand, but turns the knobs with its motor when being told to do so by the software would already be enough. I was thinking that maybe there are already components that achieve something like this, but I guess there aren't?

johndg:
Why? I thought you were boxing everything in, with motors turning the knobs.

Well the knobs need to be accessible by hand for EQ adjustments, it's supposed to be a hardware midi controller after all. I'd just like the added feature of rotating the knobs via software when necessary. For example, if I turn the knobs in my virtual EQ,using my mouse, I want the knobs on my hardware controller to rotate the same way, so that there can't be any differences in position between the two. That's not exactly why I need this feature, but I think maybe it makes it easier to understand what I was thinking about.

I guess I could use an optical encoder instead? I just read in a different forum that it can turn indefinitely, is that true? Then I could use LEDs around the encoder to indicate the current rotation of the knob. If I would make changes in my digital EQ plugin, I could send the difference in rotation to the arduino software and simply set it as the new default on the hardware controller. This would then also be indicated by the LEDs, obviously. If I would make changes on the hardware controller, I would also calculate the difference in rotation and send it to the arduino software and then to my digital EQ. It's a similar system to how the "Softube Console 2" works, do you think it could work?

jannesd:
more specifically if there are potentiometers that have a built in motor or so, that could do this?

https://www.potentiometers.com/alps_motorized_rotary.cfm

dougp:
https://www.potentiometers.com/alps_motorized_rotary.cfm

Thanks so much, that is exactly what I was looking for. Have you used this before? Will I be able to turn the knobs both manually by hand and using only the motor itself?

jannesd:
Have you used this before?

Nope, your description just put me in mind of the remote volume control on my Sony receiver so I went to the webs and ... viola!

jannesd:
Will I be able to turn the knobs both manually by hand and using only the motor itself?

Probably.

jannesd:
Will I be able to turn the knobs both manually by hand and using only the motor itself?

The 3 items on the page linked to all state: "Both Manual and Motor actuation supported". you'll have to find another supplier, tho', unless you're going into mass production. The MOQ from them is 1200 off!

If you're still around, have a look at this.