Introduction
This guide will show how to take a freshly installed Raspberry Pi and have it operate as an OS-discoverable MIDI I/O device. It will also provide some examples of using various Python libraries to get MIDI data into and out of the programming environment.
UPDATE – Jun 9, 2022.: This guide has been updated to fix some issues with the latest Raspberry Pi OS version. Added new examples. Big thanks to Marting Woolley for his contribution.
UPDATE – Aug 14, 2022.: Added old guide link and some community projects using MIDI board.
What we need
- Raspberry Pi A+/B+/2/3B/3B+/4B
- MIDI Board for Raspberry Pi
- A MicroSD Card
- Set of 4 Nylon M2.5 Screws
- Set of 4 Nylon M2.5*11mm Female to Female Standoffs
- Set of 4 Nylon M2.5*5mm Male to Female Standoffs
Assembly
Use the nylon screws and standoffs to assembly the Raspberry Pi together with the MIDI Board, as shown on the image below: 
First time setup
We tested all the examples in this document on a Pi 4B using Rasperry Pi OS, version April 2022). The first time, it is necessary to use a screen and keyboard to set the Pi up. Thereafter, use your method of choice to access the Pi’s OS. All steps are mandatory unless otherwise stated.
Installation
Update/Upgrade
Perform the update and upgrade as described here: https://www.raspberrypi.com/documentation/computers/os
Python Examples
The examples use the serial library to make it easier for everybody to test the board functionality.
MIDI in over Serial (example_1_midi_in.py)
This example shows how to:
- Lists some types of MIDI messages received in hex such as note on/note off of the MIDI device connected.
import serial
ser = serial.Serial('/dev/ttyAMA0', baudrate=31250)
message = [0, 0, 0]
while True:
i = 0
while i < 3:
data = ord(ser.read(1)) # read a byte
if data >> 7 != 0:
i = 0 # status byte! this is the beginning of a midi message!
message[i] = data
i += 1
if i == 2 and message[0] >> 4 == 12: # program change: don't wait for a
message[2] = 0 # third byte: it has only 2 bytes
i = 3
messagetype = message[0] >> 4
messagechannel = (message[0] & 15) + 1
note = message[1] if len(message) > 1 else None
velocity = message[2] if len(message) > 2 else None
if messagetype == 9: # Note on
print('Note on : 0x' + ''.join('{:02x}'.format(x) for x in message) + ' note=' + str(note) + ' on channel ' + str(messagechannel))
elif messagetype == 8: # Note off
print('Note off: 0x' + ''.join('{:02x}'.format(x) for x in message) + ' note=' + str(note) + ' on channel ' + str(messagechannel))
elif messagetype == 12: # Program change
print 'Program change'
MIDI out over Serial (example_1_midi_out.py)
This example shows how to:
- Play note C3 over and over again on a connected MIDI device.
import serial
import time
ser = serial.Serial('/dev/ttyAMA0', baudrate=31250)
channel = 2 # this represents channel 3
note = 60
velocity = 100
note_off = 8
note_on = 9
msg_note_on = bytearray([(note_on << 4) | channel, 60, 72])
msg_note_off = bytearray([(note_off << 4) | channel, 60, 72])
while True:
print(str(hex(msg_note_on[0]))+' '+str(msg_note_on[1])+' '+str(msg_note_on[2]))
ser.write(msg_note_on)
time.sleep(1)
ser.write(msg_note_off)
time.sleep(1)
Community Projects
Check out some of the projects that community is sharing with all of us using the OSA MIDI Board or similar:
- Octopy: https://github.com/dcooperdalrymple/octopy
- Bulky MIDI 32: https://github.com/tebl/BulkyMIDI-32
Old guide
If somebody finds usefull the old guide that was posted, please check it out HERE.
I hope this is useful – I pulled together the steps I used (including the video above) to run TTYMIDI as a service so it is always available for sequencers, synthesizers, etc.
https://aidanblack.github.io/RPiMIDI.html
Hello All, i fought for many months to make it work and i have finally been able to use it ! You need to change the uart config and switch the Bluetooth uart to somewhere else ! Follow the tuto here !
Hi Oriol, I am trying to revisit this the last time I was not successful, can you confirm where is the latest guide? Or please email it to me. Thank you.
Hi Oriol,
I trust you are well and continue to be keeping safe.
I have revisited this again after a hiatus.
Could you point me to the latest install instructions?
W/o updated instructions I can see, I went ahead and try again:
Steps;
1) Use an fresh RPI ( sudo apt full-upgrade done and rebooted)
2) I place the OSA Midi Board onto the RPI
3) Put power
4) Immediately, the TX light turns on and never turns off ( same as my observation the first time I asked for your help 5) On OSA Midi Board connect MIDI out to MIDI IN of my groovebox
6) Ensure I am setup to receive MIDI IN of my groovebox from Channel 3
7) Run the latest example you have posted – “MIDI out over Serial (example_1_midi_out.py)”
6) No sound coming from the python script, TX light forever ON.
7) 🙁
( My unit is Raspberry Pi 3 Model B v1.2 )
Can you help me in trouble shoot? Or could it be that I have a faulty Midi board?
Thanks Again, Joseph
Hey Oriol,
I think you are using the wrong baudrate in the two python scripts above. I was not able to get it working until I changed the baudrate to the MIDI baudrate of 31250 (http://www.gweep.net/~prefect/eng/reference/protocol/midispec.html). Now its working well.
Just wanted to mention it in case anyone faces the same problem. However thanks a lot for the tutorial 🙂
Best, Florian
Thank you very much Florian! You are right, so just changed that!
Best,
Oriol.