morch1/rpi-usb-midi-host

use Raspberry Pi Zero as USB MIDI host device

rpi-usb-midi-host

turn a Raspberry Pi Zero into a USB MIDI host device for your synths and sequencers

this script was created for the following hardware specifically:

• Raspberry Pi Zero W
• Waveshare 4 port USB hub hat

it may need to be modified to work with other models

how to use

1. create config file

   config file should be called /boot/midihost/midihost_config.py
   (look below for examples)

2. make the script auto-run when Raspberry Pi boots

   # /etc/rc.local
   ...
   
   sudo python /home/pi/rpi-usb-midi-host/attach_midi.py
   
   exit 0
   

3. make the script auto-run when devices are connected

   one way is to create udev rules for your devices, for example:

   # /etc/udev/rules.d/midihost.rules
   
   # op1
   ACTION=="add", ATTRS{idVendor}=="2573", ATTRS{idProduct}=="001a", RUN+="/home/pi/rpi-usb-midi-host/attach_midi.py"
   
   # keystep
   ACTION=="add", ATTRS{idVendor}=="1c75", ATTRS{idProduct}=="0288", RUN+="/home/pi/rpi-usb-midi-host/attach_midi.py"
   
   # circuit tracks
   ACTION=="add", ATTRS{idVendor}=="1235", ATTRS{idProduct}=="0139", RUN+="/home/pi/rpi-usb-midi-host/attach_midi.py"
   
   # microfreak
   ACTION=="add", ATTRS{idVendor}=="1c75", ATTRS{idProduct}=="0601", RUN+="/home/pi/rpi-usb-midi-host/attach_midi.py"
   

4. (optional) enable read-only filesystem using raspi-config

   this will let you unplug the power of your raspberry pi without having to shut it down and without having to worry about corrupting the sd card

config examples

the file /boot/midihost/midihost_config.py should define a variable called CONNECTIONS containing a list of MIDI connections that will be made. each connection should be provided as follows:

((source usb port, src midi port), (destination 1 usb port, dst 1 midi port), (destination 2 usb port, dst 2 midi port), ...)

• the first value in each tuple is the ID of the usb port (they are labeled on the PCB of the Waveshare USB hub hat)
• the second value should usually be 0 unless the connected USB device provides more than one MIDI port

here are some examples:

# use device connected to usb port 1 as midi input and usb ports 2-4 as midi outputs
CONNECTIONS = [
    ((1,0), (2,0), (3,0), (4,0)),
]

# connect 4 usb ports to each other (all data coming from each usb midi port will be sent to the other usb midi ports)
CONNECTIONS = [
    ((1,0), (2,0), (3,0), (4,0)),
    ((2,0), (1,0), (3,0), (4,0)),
    ((3,0), (1,0), (2,0), (4,0)),
    ((4,0), (1,0), (2,0), (3,0)),
]