Weird question

[tpresto]

here's a weird, perhaps silly, question:

I've been controlling midi devices with usine, for a while -- mostly an M13 guitar FX unit. I have other guitar stompboxes that have the phono style control input (i.e. analog expression pedal input). Is it even possible for me to somehow program usine to control these effects via phono cable? That would be unreal!!

If it is possible, how could I do this?

[23fx23]

very interesting question.
im not an expert on those thing, and very curious on how some more electrical expermimented people could answer..

i feel most of the inputs you describe are usually resistances, the pelal plugged into is kind of different shape equivalent of a potentiometer . voltage + comes from one wire out of pedal, go to the variable resistance (exp pedal) and go back to the other wire of the 2 poles of jack, so the voltage comes from the unit itself, not the external, wich is different of ie old cvs inputs of very old synthetiser, wich were feed with an independant ext +-voltage,
...so not sure it's possible to feed it safely, wondering...

but if allowed then could be easy to output some audio signal from usine, going to an amplifer correctly set to calibrate to the good voltage range the unit can admit, starting at very low levels to be safe. then, as audio is an array in usine , generating each bloc an array filled with the wanted value in 0..1 range, with a size of buffer size should do the job. (using bloc size module to get buffer size, and fill Array module to set the value and fill the array , directly connected to the audio output).

[Clearscreen]

Would an arduino controlling a hi-res digipot do this?

[nay-seven]

what about a midi to CV/gate interface..?
i suppose you can find many kits/products for analog synth .?
depending of the voltage the pedals are waiting..

[tpresto]

Excellent answers -- we're definitely moving this thing forward. Thank you!!

I'm not incredibly familiar with the arduino, but they're programmable with scripts, right? I'm thinking you probably could, assuming that you were knowledgeable of the language. Could you have Usine control the arduino?

Also, I think I might be able to find a kit that does this, but I think that there is a way to program usine to trick the pedal into thinking it's connected to an analog source -- 23FX23, you got me to thinking:

If I were to measure, via multimeter, the baseline "control pedal" output voltage(V), I would have a good starting point. Let's assume that the "control pedal" input is intended for an expression pedal -- nothing more than a variable resistor. Having the baseline output voltage (V), couldn't I have usine output audio with voltage values < V, giving the impression that it is being resisted? Or does an audio signal carry any voltage at all? if not, I'm not sure this would ever work...

[headphoner]

Hi,

You could work with usine+ midiyoke+pduino(puredata)+arduino

I didn't find information about arduino cv gate

[23fx23]

@tpresto

that's what i thought about too. usine will generate 0...1 audio 'virtual' signal, that out of main audiocard will be converted to ie 0..200mV if the amplifier gain volume is at a certain let's say low position, then 0...5V if cranked up at high levels (or something like that, no clues about real ranges, but it is electricity..) . So the Max calibration i feel should be made with the amplifier, not directly from usine. it could be also possible to do the reverse thing: always set the amplifier to a certain possition(ideally secured) then caliber from usine but it would be more dangerous imo, cause accidentally you could send overload signal).

but the real question is would this trick as you said would giving the impression that it is being resisted?

im not really sure of this but in my head it's like having two batteries: the base unit and the external.
the schem looks like by default the result of pedal (imagine a lamp, is straight conected to it's battery +and-, with a variable resistance on +wire). so if we plug a new signal instead of resistance, it looks like + of unit goes to - of new signal, then + out of second signal go back to lamp, wich result in booth signal are added together.

so to be secured, the result send out of usine should sustract first orinal max range, values sould be always negatives,
-1 + (value in 0..1 range) go to audio amplifier that will send ie -5..0 V that will be added to original 5V of base unit.

but all of this is pure speculative theory