If you do orchestral programming, you know that MIDI faders are absolutely essential to achieve a sound that wouldn’t be passed of as “MIDI-like”. What happens when you really, really want a MIDI controller with a bunch of faders, but don’t feel like spending *that much* money on one?

Well, you build one.

In this series of posts, I will present my take on the DIY MIDI controller, which has 4 faders, 4 rotary encoders, and a 4×4 key matrix, all of which are fully programmable via an onboard LCD. Instead of designing a custom PCB for this project, which, in hindsight, would have greatly simplified its development, especially when it came to writing the firmware, I chose to use whatever I had on hand, which meant:

Turns out, not getting a microcontroller that has enough IO pins is really just asking for trouble, as the firmware for this thing could only be described as an abomination. Too many things running concurrently, all having rather strict timing requirements. I will present to you the many challenges I faced trying to get everything to work correctly together while still maintaining the responsiveness of the user interface and inputs, and how I eventually solved all of them.


But first, an overview of what’s to come

The hardware is pretty routine stuff: various components connected to a microcontroller dev board in (mostly) the way you’d expect. There are a few interesting bits which arised as a result of me using all those IO expanders though, and I will cover them one by one as the series progresses.

But here is a quick overview:

Instead of a large schematic with everything on it, I think a better approach would be to break it up into sections: a series of posts each containing the schematic of one particular aspect of the hardware, along with a breakdown of the code required to drive it and chronicles of the many hours I spent banging my head on the table trying to fix issues that cropped up. Then, I’ll cap it off with a summary of how it all comes together, and address the various improvements that I think could be implemented.

Here we go!