Map Mod Wheel to Velocity

Andrew J

Is it possible to use the Map Mod Wheel setting to map to Velocity? I don't know how I got it to work, but I have managed to connect a Teenage Engineering Ortho Remote (underrated little device) via BLE MIDI. Turning the remote sends CC Modulation by default. I know I can do aftertouch, and CC's 1-127, but Velocity would be cool, as that allows me to control the filter on many of my synths and samplers. Anyone know if this can be done?

Andrew J

Wait, I forgot velocity and midi cc aren’t the same. But aftertouch works great via Bluetooth and I don’t notice any latency, pretty sick 😝

grit

Well it can be done if you just use the modwheel value as a scaling value, would be something like this (untested but I hope it explains the idea):

EDIT: I suddenly remembered there is a RK002 MIDI channel volume control DUY in the portal, you can see the code here, you can set levels for any of the 16 channels individually https://duy.retrokits.com/coder.php?guid=6c83c0a3-aaec-4a85-83e3-823acd6a32dd

float scaleval=1;

bool RK002_ControlChange(byte channel,byte ccnum, byte ccval){
  if(channel==0){ // in midi channel 1
    if(ccnum==1){ // cc1 = modwheel cc number
      scaleval=ccval/127; // scale factor will be 0.0 to 1.0
    }
  }
  return false; // block CC modwheel thru 
}

// handle note off
//
boolean RK002_onNoteOn(byte channel, byte key, byte velocity)
{
  // (try to) find inside keybuffer:
  if(channel==0){ // midi channel 0
    RK002_sendNoteOn(channel,key, (byte)(velocity*scaleval));
    return false; // omit original note
  }
  return true; // thru other channels as is
}

Bruno

@grit is modwheel mapping global or can i have a remap dedicated to an out port or midi channel? I want to keep mod wheel for my moog, but have it mapped to velocity when controlling my dx7 (as a “timbre” controller).

Bruno

@grit or could i (would i need a) rk2 going into my dx7 to do that for dx7 only?

Bruno

Chat gtp says this diy should allow to offset velocity played with modwheel setting, is that correct?
-- RK-002 Script: Mod Wheel offsets Note Velocity

local lastCC1 = 0 -- default offset is 0

function midiEvent(event)
if event.type == midi.cc and event.cc == 1 then
-- Store mod wheel (CC1) value
lastCC1 = event.value
return -- suppress CC1 from output
elseif event.type == midi.noteOn then
-- Add CC1 value to original velocity, clamp to 1–127
local newVelocity = event.velocity + lastCC1
if newVelocity > 127 then newVelocity = 127 end
if newVelocity < 1 then newVelocity = 1 end
event.velocity = newVelocity
send(event)
elseif event.type == midi.noteOff then
send(event) -- pass through Note Off
end
end

grit

the modweel map code remaps only on midi channel 1, on other channels it will pass as modwheel, so if you have the sender keyboard and dx7 on channel 1 and set the moog to channel 2 it would work again normally if you send on midi channel 2.

I've seen a few samples now from people using ChatGPT as code generator and it seems to have lost it's mind a bit - using different language flavours liky python instead of C++.. the 'event.value' readout is not how the RK002 coding works. Also I do not see any extra functionality in the code you posted compared to the original one above. You want to be able to set an offset for the velocity somehow?

Bruno

the modweel map code remaps only on midi channel 1 - good to know, and good news, tx!
Yes, my goal is to either offset, or simply replace keystroke velocity with modwheel, alternatively im thinking of mapping it to aftertouch (as my keyboard doest support it)
Im intrigued by the rk002 but learning the programming language is offputting, i dont really know what/where to learn it, which is a shame as it seems extremely capable device.

grit

The thing about the RK002 is is that it can do anything and we didn't want to limit it with visual building blocks for example. DUYs like the RK002 nanokontrol sequencer or FB01 editor are just not doable in visual interface systems, this is way more powerful. We added some components in for polymux, keybuffer, arpeggiator to make those things 'easier' to manage but putting it together follows c++ which is what you also see in arduino boards - and there are a lot of online examples for it.
In the DUY portal I can just pre-compile this small script above and make it ready for direct upload so you don't have to program anything, just connect the RK002 and upload the DUY to your RK002. But in order to finish it up I do need to know how you want to do the offset value because that's not clear to me. I could use a site parameter so you can change it after the upload but if you want to change offset/aftertouch switch in realtime you probably need to reserve another controller for it to set it while you're playing. I'm not sure what your specific setup can provide. The link below compiles straight into the RK002 and will ask you what midi channel you want to use after you uploaded it, the scale factor is changed from 0 to 1.5 so you can also amplify your played notes:

https://duy.retrokits.com/8fdb5709-4778-466d-8c8e-2153415c6b61

There's a more advanced mapper on the RK002 by the way, which allows you to change velocity response overall and has a HTML interface to generate velocity curve maps:
https://www.retrokits.com/rk002/duy/curves/

Bruno

This is incredible - how can i dive in to learn this? Is there a book / webresource you can recommend to learn this? Also, can one test a script for errors before loading it onto rk002 to avoid constant unplugging?

grit

Normally I'd say chatGPT does a nice job explaining how this all works but I noticed lately the default seems to be soiled (or the C++ steered in the wrong direction, I'm not sure). I did a chat ant tried relearning:

first I tried pointing to the correct reference library:

these are the c++ code reference library pages from the Retrokits RK002:
https://duy.retrokits.com/assets/rk002codereference.txt

chatGPT received the code with much enthouisiasm but started out reciting from it's own memory anyway. After multiple insinuations it acknowledged it could be wrong. I pasted a note handler function like

#define TAPMIDICHN 1
bool RK002_onNoteOn(byte channel, byte note, byte velocity)
{
  // receive any note-on on the TAP channel: tap the internal clock generator
  if (channel == (TAPMIDICHN-1))
  {
    RK002_clockTap();
  }
}

now it seemed to find more structure in the RK002 syntax, I uploaded the sketch here and all and all it now gives good tips, I exported the log, perhaps you can use it on other pieces of code to learn.

https://chatgpt.com/share/6864eb2e-efa4-800e-9660-ae9f205b4c7b