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Conference napalm::commusic_v1

Title:* * Computer Music, MIDI, and Related Topics * *
Notice:Conference has been write-locked. Use new version.
Moderator:DYPSS1::SCHAFER
Created:Thu Feb 20 1986
Last Modified:Mon Aug 29 1994
Last Successful Update:Fri Jun 06 1997
Number of topics:2852
Total number of notes:33157

2214.0. "Foot-->Hand Controller on Korg T2" by FGVAXX::LAING (Soft-Core Cuddler*Jim Laing*282-1476) Tue Dec 26 1989 13:43

    I just got a KORG T2 (just in time for Christmas!) ... it has 1/4"
    jacks for 2 "foot controllers" which, according to the manual, can
    be either continuous controllers or switches.  I already have enuf
    "stuff" on the floor, so I don't want to add more foot controllers,
    BUT i'd like to use these jacks.
    
    My idea is simply this: why not wire up a couple of continuous
    controllers (and/or switches) that I mount ON the keyboard, i.e.
    a couple of rotary pots or sliders that I build into a little box
    and put on the keyboard ... so I can have a little bit of "real-time"
    control over 2 parameters using my hands rather than feet!
    
    My question is this: what's the electronics behind a "continuous
    controller?"  Is it standard, i.e. same for any modern keyboard,
    or do I need to see what KORG specifically puts in their foot
    controllers to know how to build the "hand controller" version I
    want?
    
    Any help would be appreciated!
    
    	-Jim
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2214.1It's just a pot.TALLIS::PALMERColonel ModeTue Dec 26 1989 14:355
    A continuous control is just a potentiometer in disguise. Not all
    companies have the same standards, though, so you might want to read
    your manual or call Korg to find out what value you need for the pot.
    
    Chris
2214.2why not go all the way?MIZZOU::SHERMANECADSR::SHERMAN 235-8176, 223-3326Tue Dec 26 1989 15:0617
    My guess is that you want a linear taper.  Could take a VOM to a foot
    controller that you "borrow" from a store to get the value.  Should be
    easy to mount a pot (rotary or slide) onto a box.  Might even sell it
    via mail order.   No reason why you couldn't have a switch in parallel
    with the pot.  You would have to do something fancy to get a spring
    return to zero or to center.  That feature might be difficult to do.
    
    What might be neat might be to go all the way and create a 
    microcomputer-controlled replacement for a foot controller.  Add
    touch-sensitive pad so that you can slide or point your finger across it 
    to vary things.  Make the bar square so you can control two parameters
    at once (something like a Koala pad).  Make it programmable via MIDI to 
    sample and hold, return to zero, invert, return to center, be controlled 
    via variable-speed, variable-wave LFO, dynamically alter the
    charactersitics of the finger pad, and so forth.  
    
    Steve
2214.3be creative; make innovative interfacesMILKWY::JANZENTom FXO-01/28 228-5421 MSI ECL TestTue Dec 26 1989 15:1812
>    with the pot.  You would have to do something fancy to get a spring
>    return to zero or to center.  That feature might be difficult to do.
    not if you buy a pot with a center detente in the first place.
    Mouser Electronics or DigiKey may have them; well I know Mouser does
    because I bought one from them to replace one I broke.
    
    You should use them for switches activated by laser-diode beams.
    Or make a circuit that puts out a voltage proportional to your
    heart rate.  Or make a circuit that measures your perspiration.
    When you werent playing music, you could use it to tell if you were
    lying.
    Tom
2214.4add voltage controlTALK::HARRIMANMeanwhile, back in the jungle,Tue Jan 02 1990 15:0814
    
    
    re: .-1 "it's just a pot"
    
    not necessarily. Certainly on my Korgs and Ensoniqs, the pot is biased
    with a voltage source, not supplied by the board itself. 
    
    I was just playing with this back in November, which was why I ended
    up buying the FaderMaster - sure, for $1.50 you can build yourself a
    single potentiometer with voltage source (well, maybe a bit more than
    $1.50 but...) and it'll do whatever the input to the board says (i.e.
    volume or filter cutoff, or whatever). 
    
    /pjh
2214.5I've had it apart, I know what's thereGUESS::YERAZUNISIf he was a drummer, we all woulda been gonersTue Jan 02 1990 15:377
    
    Uh, on _my_ ESQ-1, the analog foot-pedal jack supplies voltage to the 
    analog pedal (which contains naught but a potentiometer).
    
    The pedal definitely does NOT contain a battery or other power source.
    
    	-Bill
2214.6whateverTALK::HARRIMANMeanwhile, back in the jungle,Tue Jan 02 1990 18:149
    
    re: .-1
    
    but on _my_ EPS, it wants a CV of 0-12V DC. It does NOT supply the
    voltage.
    
    Likewise, my polysix wanted 0-6V 1V/oct on the "CV pedal". 
    
    /pjh
2214.7Powered CV pedal?FGVAXX::LAINGSoft-Core Cuddler*Jim Laing*282-1476Tue Jan 02 1990 19:393
    So, the EPS pedal is powered, i.e. by battery or "wall bug"?
    
    -Jim
2214.8I think "both"TALK::HARRIMANMeanwhile, back in the jungle,Thu Jan 04 1990 17:1916

	dunno, I don't own one, I just read the spec in the EPS manual for it.

	The "pedal" I used was a rotary pot and a 9V battery. I wasn't able to
	get any volumes higher than 85 on a 0-127 scale, so it follows that
	a 12V battery would have gotten me to 127. Conversely, when I tried 
	a AA battery, it only went from 0-15 on a 0-127 scale.

	Although I don't really know this, I'd suspect that the EPS pedal
	probably uses an op-amp to limit current so your battery doesn't
	waste itself too fast. Probably also so that the wall bug doesn't
	waste itself either. But this is all purely conjecture based on
	logic.

	/pjh
2214.9EPS pedalKEYBDS::HASTINGSFri Jan 05 1990 15:489
    I own one and there is no power for it. Unless I am badly mistaken, it
    is the same pedal that the ESQ-1 uses. 
    
    Any standard volume pedal can be modified to work with Ensoniq gear,
    you just need to re-arrange a couple of the wires. Transoniq Hacker had
    an article on this a while back. If you'd like, and if I can find it
    I'll post it here.
    
    	Mark
2214.10OHM my, resistance value required :(AISG::MISKINISTue Oct 09 1990 23:236
    Anyone know what the POT rating is for a "pedal"?
    
    _John_  Who picked up 3 (that's all there was) pedals at a surplus
    	    store, and want's to use them with is keyboards...  They
    	    have a pot in them (2 50Ks and 1 25K) but they're not working...
    
2214.11It varies (ouch!)PAULJ::HARRIMANAccidental TaboulehWed Oct 10 1990 15:4411

	no pun intended.

	Seriously, I think it depends on the pedal - I have one that is
	a 100k pot, and another with a 20k pot in it, they both seem to
	work nearly identically (the 20k pot has a more "responsive feel").
	nb. they're wired identically, i.e. pins 1-2 to one side, pin 3 to
	the other.

	/pjh
2214.12TROA01::HITCHMOUGHWed Oct 10 1990 15:4510
    Not all pedals use pots as they tend to develop noise. Instead they use
    an optical system and vary the light on a light dependent resistor.
    
    You may have a unit that needs one of these as opposed to a pot.
    
    50k is a good value I think and should make *something* happen if a
    pot is o.k.
    
    Ken