Hi @whirecordings, to get the monome (via serialosc) to send messages to Sonic Pi, you must configure it to send to port 4559.
This can be done in one of two ways.
Edit config file
Firstly, you can edit the config file for your monome directly. This is stored in
~/Library/Preferences/org.monome.serialosc on macOS. Within that directory you should find a
.conf file for your monome (or multiple files if you have multiple monomes). My file looks like this:
port = 15503
osc_prefix = "/monome/128"
host = "127.0.0.1"
port = 4559
rotation = 0
Note, that the application port has been set to 4559. This is the important part. Then you may need to reset serialosc to reflect the changes. By far the easiest way to do this is to restart your machine.
Talk via OSC API
The other approach is to dynamically talk to serialosc via the OSC API. This is documented here: https://monome.org/docs/osc/. This can be achieved using
osc in Sonic Pi. See their respective docs for further information.
I hope that this helps.
Finally, please do consider supporting further development (and support) for Sonic Pi on Patreon: https://patreon.com/samaaron