Raspberry Pi Pico MIDI Splitter

Thinking ahead to the type of projects that might be useful for my Lo-Fi Orchestra in the future, one thing I wanted was some kind of MIDI distribution module.  This project is based on the Raspberry Pi Pico Multi MIDI Router but has eight OUT ports connected to the Pico’s PIO rather than four IN and four OUT.

Update:

• Find the Build Guide here: Raspberry Pi Pico MIDI Splitter – Part 2

Tutorials used in this project:

• Raspberry Pi Pico MIDI Channel Router
• Raspberry Pi Pico Multi MIDI Router – Part 4
• Notes on KiCad for PCB design: Arduino Uno Dual Merge MIDI “Shield” – Part 2

If you are new to microcontrollers, see the Getting Started pages.

The Circuit

A key function I wanted on this one was some proper buffered IO for the MIDI OUTs, so I’ve used 74HCT14 hex inverters (as used by Clumsy MIDI) for all outputs – there are 9 in total, 8 on PIO ports and one on UART 0.

UART 0 also has the single MIDI IN port.

PCB Design

I was keen to keep this board within a 100x100mm footprint, as that is the cheapest option for manufacturing!  It just about works!

The UART MIDI IN/OUT breaks out at the bottom of the board.  Then there are four PIO connected MIDI OUT ports on each side.  The Pico itself can be seen at the top, with USB on the top edge.

Closing Thoughts

I’d like to build an equivalent version of this board that just has serial (TTL) outputs rather than genuine MIDI OUT ports.  But to get the level shifting working, I’d keep the use of the 74HCT14s.  The idea would be to have the Pico act as the MIDI orchestrator, ideally connected directly using USB MIDI, and then distributing MIDI out to 5V serial TTL links directly to Arduino RX pins.  But that is still a little way into the future.  It might even be nice to include some kind of MIDI visualisation via a small display too.

But this has finally used up my round of Seeed Fusion vouchers for the time being, so I’ll probably have a bit of a break from PCB design for a while until some of these boards come back, then I’ll get on with some testing!

I still have no plans to sell boards, but I am trying to make them all available via GitHub once I’ve been able to test them and can fully describe and declare any limitations.

Kevin