MIDI Piano Keyboard

Arduino meets music!

Mar 7, 2024

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Music

Components and supplies

1

10 jumper wires 150mm male

1

Arduino MKR WiFi 1010

1

Colorful Round Tactile Button Switch

Tools and machines

VMPK

Apps and platforms

1

Arduino IDE

Project description

Introduction

I would have liked to make multi-level titles (h2, h3, ...), but the Arduino's Project Hub editor doesn't allow it. The project discussion is placed after a series of useful insights about Arduino, python and MIDI protocol.

Arduino boards uses $ MIDIUSB $ library to interact as MIDI devices. Python scripts shown below use $ mido library $ to interact with MIDI devices. You should install the required libraries with a tool like pip by pasting the following commands on a Terminal window:

pip install mido

pip3 install python-rtmidi

Intro ~ MIDI Notes Number

Notes number ranges from 0 to 127 (which is the range of seven bit data). These numbers relate directly to the note to be generated. The octave is indicated after the letter note name but to confuse things a bit, middle C on a piano (which is indicated by the MIDI note number 60 ) is sometimes designated as as C3 and sometimes as C4 , depending on the manufacturer.

The frequency is evaluated assuming equal tuning based on A4 equal 440 Hz :

f = 440 * 2^((n-69)/12)

Short Table version

Operation ~ MIDI Write

Select USBMIDI_Write sketch on the section below and upload it on the Arduino board. You should now navigate to VMPK settings: "Edit", "MIDI Connections". Select ALSA as "MIDI IN Driver". You should now be able to select your board within "Input MIDI Connection" drop-down menu.

You can also test it by running read-MIDI-device.py Python script.

The Arduino board is capable of sending MIDI notes acting as a real MIDI instrument!

Operation ~ MIDI Read

Select USBMIDI_Read sketch on the section below and upload it on the Arduino board. Run write-to-device.py script to test the Arduino board as input MIDI device.

The Arduino board is capable of reading MIDI notes acting as a real MIDI manager.

Project Idea : You can light-up different LEDs of different colors (in case of RBG) based on the received MIDI note.

Operation ~ MIDI Loop

Run both write-to-device.py and read-MIDI-device.py Python scripts, then upload USBMIDI_Loop sketch on the Arduino board. The MIDI notes are being sent to the board and written back to the reading script.

The Project ~ MIDI Keyboard

Within Downloadable files section, take a look at project schematic. I've bought some fancy colorful tactile switch buttons. They make the project looks so cool!

Upload MIDI_Keyboard sketch on the Arduino board.

Every switch button corresponds to a MIDI note on the keyboard, from C3 to C4 . You can now play around and have fun with the virtual piano. The examples above uses VMPK software to test the board's MIDI capabilities. You can use this project with any software you want. I personally use it with Ardour 8 to perform live music!

Project Idea : You can change the code in order to play a whole chord with a single switch button!

Code

write-to-device.py

python

Write MIDI note n°60 ON and OFF to USB device

1#!/usr/bin/env python3
2
3# ~~~ write-to-device.py ~~~
4
5import mido # pip install mido
6import time
7
8if __name__ == "__main__":
9    # get the list of all the MIDI devices conneted
10    input_names = mido.get_input_names()
11
12    # choose the name of the USB MIDI device
13    # you want to send messages to
14    usb_midi_device_name = input_names[1]
15
16    try:
17        # open the selected MIDI output port
18        with mido.open_output(usb_midi_device_name) as port:
19            print(f"Sending MIDI messages to {usb_midi_device_name}")
20
21            # send Note On message
22            note_on = mido.Message('note_on', note=60, velocity=64, channel=0)
23            port.send(note_on)
24            print(f"Note On sent: {note_on}")
25
26            # wait for a short duration
27            time.sleep(1)
28
29            # send Note Off message
30            note_off = mido.Message('note_off', note=60, velocity=64, channel=0)
31            port.send(note_off)
32            print(f"Note Off sent: {note_off}")
33
34    except KeyboardInterrupt:
35        print("Exiting...")

read-MIDI-device.py

python

Read from MIDI device.

1#!/usr/bin/env python3
2
3# ~~~ read-MIDI-device.py ~~~
4
5import mido
6
7if __name__ == "__main__":
8    # list available MIDI ports
9    input_names = mido.get_input_names()
10    print(">>> available MIDI ports:")
11    print(input_names)
12    
13    # select desired port
14    # i.e. "Arduino MKR WiFi 1010:Arduino MKR WiFi 1010 MIDI 1 20:0"
15    input_port_name = input_names[1]
16    inport = mido.open_input(input_port_name)
17
18    # loop to receive messages
19    while True:
20        for message in inport.iter_pending():
21            print(message)

Downloadable files

Project Schematic

Project Schematic with Arduino MKR WiFi-1010

piano-keyboard.png

Documentation

MIDIUSB

Allows Arduino act as a MIDI instrument over USB.

https://github.com/arduino-libraries/MIDIUSB

mido

Working with MIDI messages and ports.

https://github.com/mido/mido