Hey

I've been thinking about making a control surface for Pure Data and I think I am diving into it soon.

Making hardware solutions is pretty new to me, so I am just looking for some tips and tricks and trying to find out how hard it is to build something.

I understand that Arduino might be a nice solution? AFAIK there is a lot of options and code base to use?

Some of the things I would like to have in my controller is:

• Endless encoders. Maybe 16-24.....
• Displays for encoder/parameter feedback.
• 16 buttons, with LEDs, that can be used for a sequencer.
• More buttons for pages and menues.
• Midi compatibility(USB), so I can connect it to my Macbook/PD.

Those are the most important things. I guess I probably need some multiplexing for this to work, when it's so many parameters and buttons?

One of the things that I am most concerned about is how I make Pure data interact with the displays on the controller?

And also thinking a bit about the endless encoders how they interacts with midi and PD. To be honest I never used an endless encoder before so not sure how it will work with PD.

I do have some experience with c++ and coding objects for Axoloti and for VCV rack and did take som courses, so I do have a bit of understanding of the software side, but not a lot about implementation into hardware solutions.

Do you guys think this is doable? If so, where should I start? Which Arduino would be suitable for this project?

Anything I missed?

Thanks in advance

@jaffasplaffa I recently built my first device, a USB midi footswitch with an arduino. A bit of googling led me to the awesome MIDI Control Surface library.

The main thing to be careful about IMO is to get the right board to communicate directly over USB (Micro, Leonardo, Teensy, see the documentation), otherwise (Uno, Nano) you will need a serial-MIDI converter software like hairless (with GUI) or ttymidi (command line).

For the LED lighting I took inspiration from my other commercial controllers, and set the arduino's code to light up the LEDs by sending a notein and then it off with a noteoff (if you have multiple colors or blinking mode, you can use different velocities, e.g. 36 1 1 for solid green on button 36 (channel 1), 36 2 1 for blinking green, 36 3 1 for red, etc.
You can also hardcode the LEDs status with the buttons status, but you may loose flexibility (especially when using Pd, but it may be more complicated to use a DAW if you have to set up when to light up the LEDs, not sure).

Now I am looking into building another controller with faders and knobs, and there I'll indeed also need multiplexers, as I believe that the bigger Arduino I could find had ~40pins. You will probably need digital pins for the buttons and LEDs, while potentiometers need analog pins (as far as I could understand so far, but I'm also new to this!).

In any case, regardless of how you initially program the arduino (e.g. only notein/noteout to control the LEDs), you can just decide otherwise later on and reprogram it (just like you would update a commercial controller's firmware) to change the note numbers of each button, add special modes to give other functionalities to the same buttons, this kind of things.

Let me know how it goes I'm hoping to get started on mine in 2 weeks or so.

Also, I'm curious about the buttons you'll choose for this!
I can't mold silicon buttons or 3d-print the enclosure myself, so I may have to go for bulky arcade buttons, not sure yet.