MIDI Setup
If you want to use cardio-crumble and don't have a hardware MIDI device at hand, you can set up a software MIDI device on your machine.
On Linux for sure -it should also work on other platforms-, you can use the real-time software synthesizer fluidsynth. It should be available via your package manager, e.g., apt install fluidsynth. Once it's installed, you can start it by running fluidsynth. You can then run cardio-crumble list_devices in a different terminal to make sure your newly created virtual port appears:
$ dune exec bin/main.exe list_devices
...
device 2
name: Synth input port (91651:0)
interface: ALSA
input: false
output: true
If that's the case, you can go ahead and use cardio-crumble with the newly created device-id, in this example device-id=2.
Notice that possibly some warnings will show up running fluidsynth. That's ok. cardio-crumble tends to work just fine with a warnings emitting fluidsynth instance in the background 😃
A simple MIDI setup on MacOS is to use the freely available GarageBand program.
Once installed, you will first need to setup a virtual MIDI port cardio-crumble can use to send MIDI data to GarageBand.
Follow the guide here to do so.
Once the setup is done, your new hub should appear in the list of devices cardio-crumble list_devices returns.
$ dune exec bin/main.exe list_devices
...
device 11
name: IAC Driver Hub
interface: CoreMIDI
input: false
output: true
You can then open GarageBand, and start a new project.
Select a Software Instrument project.
If everything went well, you will then be met with a default project, with one track set up with a virtual Piano instrument, and running cardio-crumble using the device ID associated with your newly created MIDI port will trigger notes on said instrument.
Have fun!