Any way to control an exp pedal input over midi?

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infuzedinfuzed Frets: 5
edited July 2017 in FX
Ok, so i have a mobius on top of my amp
I want to blend more of my direct signal so am considering: http://www.one-control.com/mosquite-blender-expressio.html

I want to control this dynamically
On the floor i have the ability to send control change over midi
Ideally i want my floor exp pedal that sends the control change over midi to be converted back to a signal the mosquito can understand so i can manually change (or send a preprogrammed value) the wet/dry

SO basically this is the reverse of changing expression pedal input to midi...

Any ideas/kit you know about?


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Comments

  • RavenousRavenous Frets: 1484

    Hmm you can get a MIDI-CV converter, it's for interfacing analogue synths (which take a control voltage input) to MIDI.

    Dunno if it's exactly what you need, but it's one thing to try investigating.  (Though hopefully somebody might suggest something better.)

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  • infuzedinfuzed Frets: 5
    ok, yes, heard of that type of interface for synths, thanks, hadn't considered from that angle...
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  • vasselmeyervasselmeyer Frets: 3665
    I'm sure there's a cheaper way of doing this, but my BOSS ES-8 switcher is able to  take an analogue input (from an expression pedal) and translate it into  a MIDI CC value. So, for example, I can use my expression pedal into the  EXP input of my ES-8 which translates it and sends that value to my Mobius. As an example on the "Filter" patch I can change the "F MID" parameter and I can use the Mobius as a Wah. I have  patches where the expression pedal can  speed up and slow down the rotary speed and increase and decrease the depth of the chourus.
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  • RavenousRavenous Frets: 1484
    edited July 2017

    Be aware the MIDI-CV converters I mentioned are usually depressingly expensive though. Not sure why as it should really just be a little microcontroller chip, a D-A converter chip (not sure what price these would be) and probably some cheap op-amps to buffer the output...

    Perhaps it's because the synth market is so specialised.

    Hopefully someone will suggest something cheaper!

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  • infuzedinfuzed Frets: 5
    Ravenous said:

    Be aware the MIDI-CV converters I mentioned are usually depressingly expensive though. Not sure why as it should really just be a little microcontroller chip, a D-A converter chip (not sure what price these would be) and probably some cheap op-amps to buffer the output...

    Perhaps it's because the synth market is so specialised.

    Hopefully someone will suggest something cheaper!

    Thanks
    With your terminilogy of midi to CV have found this: https://www.thomann.de/gb/doepfer_mcv4.htm

    Which is ok but does 4x what i need
    There are these micro pcb's
    http://www.midimplant.com/
    but i would need someone to craft a box with midi in and TRS out... beyond my skillset unfortunatley





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  • normula1normula1 Frets: 639
    I'm not sure MIDI to CV is what you need. I think you need something more along these lines
    http://little-scale.blogspot.co.uk/2008/05/four-midi-controlled-digital-pots-via.html?m=1

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  • infuzedinfuzed Frets: 5
    normula1 said:
    I'm not sure MIDI to CV is what you need. I think you need something more along these lines
    http://little-scale.blogspot.co.uk/2008/05/four-midi-controlled-digital-pots-via.html?m=1

    Very interesting but beyond me.
    Does not midi to cv mean midi to control voltage and thats basically what an expression pedal puts out? Variable voltage?
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  • ecc83ecc83 Frets: 1591

    https://missionengineering.com/understanding-expression-pedals/?v=79cba1185463

    It seems most expression pedals are a simple pot and resistor. What you would need therefore is: MIDI >CV>Voltage controlled resistance (FET?).

    But beware, according to that link there are no standards of voltage and type and you can uck things up if you are not 100% sure of what you do!

    Dave.

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  • ecc83ecc83 Frets: 1591
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  • RavenousRavenous Frets: 1484
    normula1 said:
    I'm not sure MIDI to CV is what you need. I think you need something more along these lines
    http://little-scale.blogspot.co.uk/2008/05/four-midi-controlled-digital-pots-via.html?m=1


    That looks great, though dunno if anyone is doing a ready-made one.

    Another alternative - maybe not to use the blender thing at all, but get some sort of small MIDI-controlled mixer? I know the big expensive mixers can be controlled digitally, maybe someone does a simple MIDI-controlled mixer with just a few channels on it? This could then be controlled to do pre-set volumes on everything...

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  • infuzedinfuzed Frets: 5
    ecc83 said:

    https://missionengineering.com/understanding-expression-pedals/?v=79cba1185463

    It seems most expression pedals are a simple pot and resistor. What you would need therefore is: MIDI >CV>Voltage controlled resistance (FET?).

    But beware, according to that link there are no standards of voltage and type and you can uck things up if you are not 100% sure of what you do!

    Dave.

    Thanks Dave, VERY useful link there, thanks
    Seems that without some more in depth skills will be very difficult to do myself
    I can't believe that no-one else has run into this issue and resolved it... would seem to me to be a fairly obvious issue.

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  • SporkySporky Frets: 27586
    infuzed said:

    Does not midi to cv mean midi to control voltage
    Yes.

    infuzed said:
    thats basically what an expression pedal puts out? Variable voltage?
    No - or at least not necessarily. Any good design will put a voltage across the expression pedal and read the position of the wiper back, but we're dealing with pedals and guitar FX "designers" here, not qualified engineers, so lots use the pot itself in the effect circuit. Bunging a voltage back in may work, may not work, or may (with an exceptionally talented designer) cause damage - though the latter is unusual.

    I'll have a look through my bookmarks - I'm sure I've found something that does this before.
    "[Sporky] brings a certain vibe and dignity to the forum."
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  • normula1normula1 Frets: 639
    Highly Liquid used to make exactly what you need, but it's sadly discontinued.
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  • infuzedinfuzed Frets: 5
    normula1 said:
    Highly Liquid used to make exactly what you need, but it's sadly discontinued.
    Ok, interesting read of google cache of the missing forum the item they had is a system to phyically move a pot, i think they still sell this pcb, so could build an enclosure with the pot acting as the wiper and connect a jack to make a connection to the physical world before moving back to the electrical to control the blender... jeez seems overly complex for such a simple requirement. lol

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  • infuzedinfuzed Frets: 5
    Sporky said:
    infuzed said:

    Does not midi to cv mean midi to control voltage
    Yes.

    infuzed said:
    thats basically what an expression pedal puts out? Variable voltage?
    No - or at least not necessarily. Any good design will put a voltage across the expression pedal and read the position of the wiper back, but we're dealing with pedals and guitar FX "designers" here, not qualified engineers, so lots use the pot itself in the effect circuit. Bunging a voltage back in may work, may not work, or may (with an exceptionally talented designer) cause damage - though the latter is unusual.

    I'll have a look through my bookmarks - I'm sure I've found something that does this before.
    Thanks for the overview Sporky. Appreciate the explanation and anything you might turn up

    Cheers
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  • ecc83ecc83 Frets: 1591

    Google 'Kenton and MIDI' They are the dog's whatsits on MIDI and CV gear but not cheap!

    Dave.

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  • normula1normula1 Frets: 639
    edited July 2017
    I couldn't see anything on their site that would fit here. I've a couple of their MIDI merge boxes that are great.
    As you say Dave, not cheap :)

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