[sdiy] Building an Ondes Martinot or French Connection stylecontroller?

[Mike Beauchamp]

Thanks ken, i was thinking this was a possible solution. Very cool..
Is this pulley something that goes around once (so it's circumference
is slightly larger than the length of the travel?) or multiple times?
If the pulley goes around multiple times that means the string goes
around the pulley multiple times as well, and would there be anything
there to stop it from getting tangled up if 10 loops of string go
around it for example?



On Dec 2, 2007 3:02 AM, Ken Stone <sasami at hotkey.net.au> wrote:
> The string slip problem is solved by anchoring the string at the ends to the
> pulley. It is not a continuous loop, but rather a long string (3 times the
> length of the travel + spare to cover the remaining distances between the
> pully and the playing area), with a one length wound on the pully, one
> length along the keyboard, and one length returning from the other end of
> the keyboard to the pulley again. Usually one end was terminated in a spring
> housed within the pulley itself.
>
> Ken
>
>
> >I've built a few simple portamento controllers, and I want to build a
> >sort of Ondes Martinot controller (Sort of like the Analogue systems
> >"French connection" controller -
> >http://www.analoguesystems.co.uk/Reviews/fconnection_review.htm). I
> >mean JUST the portamento string-ring interface, not the keyboard
> >interface. If nobody's seen one before, here's a nice video explaining
> >one.. http://youtube.com/watch?v=ybYIhomm5KM
> >
> >I've never actually seen the inside of any of these controllers and
> >I'm sort of curious as to how they might work. I'm wondering if anyone
> >has seen inside, or know exactly how they might work mechanically?
> >
> >My first guess would be to have the string wrap a few times around a
> >pulley wheel attached to a 10-turn potentiometer (or a geared down
> >single turn pot, to avoid having a pulley wheel with a circumference
> >as long as the actual playing field area). I'm wondering if maybe
> >either of these controllers came up with a way of avoiding the string
> >from "slipping" on the pulley over the course of time, or if just
> >wrapping a string around a pulley multiple times would cause enough
> >friction to avoid this (I'm reminded of old FM tuners, which I THINK
> >slip over time). Also, if there's something to deal with tension on
> >the string.. and what kind of string it might be?
> >
> >The second thing (and this one is a lot more complicated in my mind)
> >is how the "button" style volume controller works. The best solution I
> >came up with brainstorming last night would be to have the button a
> >miniature version of a cry-baby wah-wah pedal, but with a spring so it
> >returns to it's top position. The lever would be attached to a geared
> >shaft which would ride against the gear of a potentiometer (just like
> >in the wah wah pedal).
> >
> >Mike
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> >
> _______________________________________________________________________
> Ken Stone   sasami at hotkey.net.au
> Modular Synth PCBs for sale <http://www.cgs.synth.net/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>
>



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Mike Beauchamp
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