CV to pitch et al?

I’m still waiting for my Shruti / am out of town for the rest of the month, but am developing a plan of attack / budget for making the Shruti into the instrument I want it to be, AND I HAVE A QUESTION.

looking through the manual, the Architecture on p4 does not seem to indicate that I can route CV to control the pitch - that I can only route CV to filter cutoff + resonance. is this indeed the case or am I missing something?

Ahh, I see what you mean, the colors can be misleading… But you can route blue arrows to purple arrows, and purple arrows to blue arrows :slight_smile:

fantastic. thanks for the clarification.

my midi+sustain Q got my mind revisiting this topic (also while I guess I’m requesting features for future firmware upgrades…)

•basically, I want to use a ribbon controller (linear potentiometer) via CV to control note/pitch instead of a MIDI keyb. scrolling though the mod routing, there isn’t an option for “mod”->“note on” (or something like that). so, just connecting a CV in to osc pitch wouldn’t trigger a note at that pitch, it would just modify the pitch when triggered by a MIDI note-on. correct? sorry I haven’t had time to test this properly (out of the shop and into the studio for a bit).

so, I’m also inquiring as to whether this necessitates adding a “note on” destination in the mod routing, and if that would be possible, pretty please, sugar on top.

Yes if you just connect a linear pot to a CV in and route the CV to pitch, you’ll only have a fancy pitch bender ; not a substitute for a keyboard since it’ll only modulate notes triggered by another mean.

My answer for the “note on” as a modulation destination is a no: it doesn’t really fit there, and properly reading, denoising and thresholding an input to generate a gate signal that would overwrite the note on/off from MIDI is going to take code - I’m not sure there’s room for it.

Also, even if there’s a way of using an external “gate” signal to trigger notes, how are you going to generate this with only a ribbon potentiometer? The one I have doesn’t have the ability to “sense” the presence or absence of a finger on it.

thanks for the feedback, Olivier.

adding a pressure sensor under the ribbon would be able to trigger a note-on, but I see yr point about the amount of coding required to add that.

taking me a bit back to the drawing board with this then - any suggestions for a MIDI keyb that is smaller than my axiom?

Korg nanoKeys are small and fun. And when a key breaks they send you anew one without asking for the old. So you can use that for 24 other replacement keys. I just covered mine with clear cello. But really, they’re pretty fun.
But it sounds like your not looking to go through USB back to shruti so maybe a the korg micro. Listen t’me sound like the salesman. :stuck_out_tongue:

i found this:

which will probably work (and after the cost of a linear pot, not much more than the korg toys) - more assembly!


Do you think it could be programed to make use of several ribbons for extended range or would a different module be needed for each ribbon?

Alright it’s been on my mind for…months. So before I drop the cash on the controller and some soft pots I was hoping to clarify a few things. A few I might, or should, will ask the man himself but I’ve got to get this out for some feedback.

Here’s a hyperlink to the address above

I’d like to implement a series of 100mm ribbons that step through a couple of notes per ribbon.

A few straight to the point questions that arise.

They’re analog resistors with out any logic right? Can they be ganged to act as if they are longer; sharing center pins?

Can I share the power supply with the Shrut(h)i. I’m not real good with the electrical theory stuff but in my mind I’m thinking I could tap in before the power supply on the Shrut(h)i seeing that both units use 7-12 volts input. If I do that I’d need to apply the power to the ribbon controller before its supply. Or I could tap into the Shrut(h)i power at some point after the supply section and into the ribbon controller after the power supply seeing both units use 5v common. Might that cause to much stress on the Shrut(h)i???

Kind of like the power supply question: Can I hook up the MIDI outs (pins 5 and 4) from the ribbon controller to the Shrut(h)i via the backside of the ports? It would seem silly to hook up a midi port to the ribbon controller then use a midi cable to send it into the Shrut(h)i. Any thing to worry about that involves optocouples?

In the source code of the ribbon controller the first line is int softPotPin = 0; // softPot connected to analog pin 0
There appears to be several open analog pins on the board (a1-a5) could those be used to hook up the max 5 more softpots? Probably a question for Tom Scarff.

If any thing, am I on the right track here?

Softpots are like potentiometers. There’s no obvious way of chaining them together for this application. You need a bit of extra logic in the code to handle the transition between pots.

You can share the power on the unregulated side - this thing is unlikely to draw more than 50mA. OR you can use the +5V regulated supply from the Shrut(h)i and connect it to the 5V pin of this board.

Yes, you can directly hook up the MIDI out pins.

You can use the multiple analog pins on this board to connect several soft pots, but there needs to be some code change to handle the transition from one pot to the other.

Would anyone mind helping me out with the code changes needed to make this work with multiple ribbons? I’ve been corresponding with Tom and unfortunately he’s unavailable to help for a while. I don’t know much about code at all.

I have two ideas for implementing these ribbons in my case design, one simple, one more complex(but not sure). I’ll explain further.


O.K. then,

Any suggestions on where I should start? Arduino, Processing, Wiring, etc… Perhaps something else.

Recommendations for books or articles that might help me get there quicker by learning things pertinent to the application I’m looking for?

From what I can tell, Arduino is based on Wiring which is built on Processing which deals with/teaches a lot of visual computing tasks and such while Wiring is used for electronics specifically and Arduino is specific to certain hardware.

So where to start?

Please and thank you.