arduino_midi_library VS Audio

That makes me wonder how often one runs across a synth that doesn't support running status. I'm working on a MIDI controller myself, and that's a thing I probably ought to enable if I want the lowest latency.

It seems the standard MIDI libraries that Arduino uses don't enable it by default, but it's a configuration option you can turn on, along with a note not to try to use it with USB[1].

[1] https://github.com/FortySevenEffects/arduino_midi_library/bl...

take a look here

The Arduino MIDI Library [1]. Back in 2009, I learned C++ to build it and control my guitar effects pedals with custom electronics as part of my engineering degree.

[1] https://github.com/FortySevenEffects/arduino_midi_library

Your project can be broken up into a number of subprojects. For keyscanning you don't need additional hardware, just the pins from the ribbon cables going to the arduino's digital pins and ground. Since the keys are just switches (two per key, the time difference between the two switches closing giving the source of velocity), you could start with some examples from the Arduino MIDI library (https://github.com/FortySevenEffects/arduino_midi_library). To test MIDI sending you don't even need to start from the keybed just yet, and if you do, you can start with a single key. Once you've got that part figured out end to end (key press/release generates note on/off events) you can work on iterating through the matrix, CC controls etc. MIDI out can be done in different ways. With a 5 pin DIN plug you'd just need two 220 ohm resistors.

On an Arduino compatible platform the configuration of the baud rate at the bare metal layer is taken care of by the library when you call its begin() method. Looking at the example code included with the library it appears that there are no timer interrupts or anything like that required of you in order to use it. Another thing that jumps out is that the call to read() returns a non-zero value if anything has been received that you should use to predicate whether any further attention needs to be spent on it by your code. You may know this but it wasn't apparent from the loop() { MIDI.read\`() }` example that you gave above.

As i have started to combine this with Midi Implementation from FourtySevenEffects lib, i only have done a quick test with two/three strips and did discover follwing issue(s):

Using a library for the midi shield you can register two functions as callbacks. One callback for NoteOn(...) messages and one for NoteOff(...) messages. But thre is much more. In the end the source of truth should always be the docs for the library itself.

Click the link to github (second link in the article) and there's all the source code: https://github.com/FortySevenEffects/arduino_midi_library

Here’s a library that might work.

Teensy which gives you a lot of options with its audio library and GUI tool.

Teensy is more powerful than Arduino, 4.X boards are in stock, 8 sets of serial ports, and has a supported audio library

Just in case you don't want to go from low level code and up this is the library development version (there is a release version that you install into the Arduino environment as well) and this is the GUI that makes it simpler to do the layout work for the modules of your device to make it more straight forward to do the build of the design work. You drag the modules from the left into the work area and then connect them up. Once you have the layout you want you then export the code for it into the Arduino IDE. In the right hand panel is the description of each module and what commands are used for it in the IDE.

If you are targetting microprocessors, you are probably best coding it from scratch so you can optimise. Teensy 4 seems to be the platform of choice for a lot of synth projects. The Teensy Audio Library might give you a bit of a head start. Dexed-micro touch is a great open project that can give you an idea of what is possible on Teensy and the dev is quite approachable.

You can overcome the RPi scarcity by migrating the code to the Teensy platform, which aside being cheaper and less power hungry than the 2,3,4 RPi, is a lot cheaper and more easily available. Not an easy task since there's no Linux under the hood, but there are some excellent audio/midi libraries to help. They already built commercial-level synthesizers with it. By combining the breath sensor data with other pressure sensors you could end up with a very expressive instrument.

https://www.pjrc.com/teensy/index.html

https://www.pjrc.com/teensy/td_libs_Audio.html

https://www.pjrc.com/teensy/td_libs_MIDI.html

https://www.youtube.com/watch?v=z2674LdYW5I

Personally, if I need to make custom software modules and design my own PCBs, I'm almost certainly not going to use something like LightShowPi as my starting code. I'd probably use a Teensy + Audio Shield + EL Sequencer and have the Teensy Audio Library do all the FFT/beat detection. It'd be much more power efficient, easier (IMHO) to build and maintain, and it still allows for expansion options for future add-ons. Funny thing is, I actually own an El Escudo Dos, but I have found it to be a giant PITA compared to simple edge-lit "Neon" LED strips or even the newer "nOOds" from Adafruit.

> Silly question but why is the Pi necessary?

Not sure about this project, but generally it is not. All it needs is a small board capable of running Linux and the necessary drivers for external ADCs/DACs where necessary, plus the digital fx software. As an example, Guitarix runs also on ARM and can work on cheaper boards such as the Orange PI, Nano PI and many others cheaper and more obtanium than the Raspberry PI. https://guitarix.org/

In some cases you don't even need to run Linux. There are many effects projects using a cheap Teensy board plus its piggybacked audio card; it features a really powerful audio library and is compatible with the Arduino IDE.

https://www.pjrc.com/teensy/

https://www.pjrc.com/teensy/td_libs_Audio.html

The Teensy is truly amazing, to the point one can build synthesizers that just a few years ago would cost hundreds of bucks. Take a look for example at the TSynth, 100% Open Hardware & Open Source, also available in kit.

https://electrotechnique.cc/

Demo here: https://www.youtube.com/watch?v=uCA2L7CeWSE