[sdiy] Two parameter mechanical controller thoughts....

[Pete Hartman]

The Collidoscope itself is actually a lot simpler on the inside that it
would appear from the videos.

It uses a Teensy to convert the encoder output and softpot position (and
any other sensors) to midi messages.

It has MIDI from the keyboard and the Teensy going to a raspberry pi that
displays the waveform on a large monitor.

It uses a FocusRite interface to handle audio in and out duties for the Pi.

The display monitor is mounted under the surface of the "table" with a
divider down the middle.  The Pi does all the synthesis and display work.

I was kind of liking the softpot idea, because I have one already set up as
the controller for an Appendage (check electro-music.com for some of the
details about the Appendage, it's a very feature-rich ribbon controller).

One advantage it has is that the belt/pulley idea requires that you have
additional space to the side of the carriage for mounting the belt/pulley
behind the panel.  The softpot, if mounted appropriately doesn't have to
add more than ~8mm to the width of the overall mechanism, and depending on
the details, could conceivably add zero.  I'd expect mounting an encoder
and belt and pulleys for the belt to take up more than that.

Pete




On Fri, Jun 7, 2019 at 12:27 PM Ben Bradley <ben.pi.bradley at gmail.com>
wrote:

> I remember the "Crazy Synthesizer Demo" from a few years ago, and just
> looked at it again. From what I remembered, I thought it was just a
> big touch-screen like an ipad, but I see it's a long slider with a
> round knob.
>
> There's also the ribbon controller like on the Micromoog, and I recall
> seeing one that's substantially longer. That's not what you want, but
> it's another idea.
>
> I kind of like the belt/pulley idea. This could go to a
> high-resolution rotary encoder, microcontroller and a high-resolution
> DAC to generate a precise control voltage that feels "analog."
>
> On Fri, Jun 7, 2019 at 1:13 PM Quincas Moreira <quincas at gmail.com> wrote:
> >
> > I think I'd lose the softpot too, and use some kind of belt/pulley to
> turn a rotary pot/encoder
> >
> > On Fri, Jun 7, 2019 at 9:58 AM thresholdpeople via Synth-diy <
> synth-diy at synth-diy.org> wrote:
> >>
> >> The thing with CNC gantry systems like 3D printers is that most lower
> end ones use stepper motors for both the drive and positioning, so running
> them in reverse won't be possible to create a control voltage based on
> position with out a whole lot of extra circuitry. However they may often
> have parts like linear bearings, precision-ish shafts, and all sorts of
> other hardware that could be re-purposed.
> >>
> >>
> >>
> >> Check out Author & Punisher - http://www.tristanshone.com/ - he makes
> awesome controllers, and has one or two that are as you're describing,
> Pete. He's pretty open about construction and functionality.
> >>
> >> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> >> On Friday, June 7, 2019 9:55 AM, Pete Hartman <pete.hartman at gmail.com>
> wrote:
> >>
> >>
> >>
> >> On Fri, Jun 7, 2019 at 7:07 AM bbob <fluxmonk at gmail.com> wrote:
> >>>
> >>> i'd go wireless - bluetooth or ble from whatever controls are on the
> carriage, and a time-of-flight sensor to measure the carriage position.
> there's probably a lot of hardware bits you could repurpose from folks
> developing diy 3d printers for the carriage mechanics.
> >>>>
> >>>>
> >>
> >> I'm not sure wireless would be practical for within-the-module
> communications in a Euro module or standalone controller meant to interface
> with Euro.....
> >>
> >> 3D printer carriages would be a good source of inspiration though.
> >>
> >> The linear bearings at McMaster look really interesting, I'll have to
> spend some time digging around in that stuff.
> >>
> >> Thanks
> >>
> >> Pete
> >>
> >>
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> >
> >
> > --
> > Quincas Moreira
> > Synth Diy Guy
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