Command line script to bridge Serial to MIDI.

Code and original instructions by raspy135 at the serialmidi repository

Works with any micro controller boards such as Arduino, ESP32, using their UART-USB interface.

Processes most of MIDI messages. Has very low latency (probably less than 5ms).

This is aimed at being used with Ableton Live at Malmo University's sound design courses.

This script needs python-rtmidi, PySerial and Python 3.

1. Install Python 3 (MACs come with this by default)
2. Install pip (MACs come with this by default)
3. In a terminal window, execute pip3 install python-rtmidi
4. In a terminal window, execute pip3 install pyserial
5. Download serialmidi.py from this link in the repository, copy it in a folder of your liking

1. In a terminal window, navigate to the folder where you downloaded the serialmidi.py program using cd NAME_OF_FOLDER
2. Using the Arduino IDE, identify the port your Arduino is connected to. In MAC OS X, the port will be called /dev/cu.usbmodemXXX, in Windows COMXXX and in Linux /dev/ttyACMXXX, where XXX represents a unique identifying number.
3. Make sure your microcontroller board is running a code that could be used to trigger your midi device. For example, the following code example is used at Malmo University, Sweden, to convert an Arduino Uno into a midi device interfacing Ableton Live.
4. Configure your virtual midi device input / ouput in your computer so that the port name is IAC for MAC or loopMIDI for Windows. Check the small details that might affect the configuration, i.e. in Swedish computers, the communication bus is called Buss (with two s).
5. In a terminal window, and depending on your operating system, use the following code to start the communication, change SLAB_USBtoUART to correspond the serial port you will be using.

MAC OS X / Linux example
$ python3 serialmidi.py --serial_name=/dev/cu.SLAB_USBtoUART --midi_in_name="IAC Bus 1" --midi_out_name="IAC Bus 2"

WINDOWS example
$ python.exe .\serialmidi.py --serial_name=COM4 --midi_in_name="loopMIDI Port IN 0" --midi_out_name="loopMIDI Port OUT 2"

For Malmo University's MAC computers, it is very likely that the default configuration will be:

MAC OS X / Linux example
$ python3 serialmidi.py --serial_name=/dev/cu.usbmodem2101 --midi_in_name="IAC Buss 1" --midi_out_name="IAC Buss 1"

6. Open your midi instrument, at MaU it is Ableton Live, open the example provided by your teacher, and check whether it produces sound.

1. Run serialmidi.py -h to see this help.

$ python3 serialmidi.py -h
usage: serialmidi.py [-h] --serial_name SERIAL_NAME [--baud BAUD]
                     [--midi_in_name MIDI_IN_NAME]
                     [--midi_out_name MIDI_OUT_NAME] [--debug]

Serial MIDI bridge

optional arguments:
  -h, --help            show this help message and exit
  --serial_name SERIAL_NAME
                        Serial port name. Required
  --baud BAUD           baud rate. Default is 115200
  --midi_in_name MIDI_IN_NAME
  --midi_out_name MIDI_OUT_NAME
  --debug               Print incoming / outgoing MIDI signals

2. Figure out serial port name and baud rate. Baud rate default is 115200.
3. Run serialmidi.py --serial_name=[serial_port] --baud=[baud]. Make sure it doesn't say "Serial port opening error.".
4. The script prints recognized MIDI devices. Use one of listed name as argument of --midi_in_name and --midi_out_name. Here is an example on OS X.

INFO:root:IN : 'IAC Bus 1','IAC Bus 2'
INFO:root:OUT : 'IAC Bus 1','IAC Bus 2'

You may want to use MIDI loop bus such as IAC Bus for OS X, or loopMIDI for Windows. Also, you need to use different bus in order to avoid signal loop.

5. If it is not working, try --debug option. It will dump all incoming / outgoing MIDI messages. Or create an issue on the GitHub page.

If, when running any Python commands (such as Python3 or pip3) your computer throws the error: xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), ... this means that you don't have any development tools installed. They are for free, install them using:

xcode-select --install

in a terminal window. This will install all of the command line tools needed for development, including Python3, which is the basic requirement for serialmidi to work.

• Tested with OS X Catalina with ESP32 board, and Windows10 with loopMIDI.

• It's originally made for a DIY ESP32-based synthesizer, MIDI IN has been extensively tested, but MIDI OUT might throw some errors.