DEMO Star Wars Theme 6-Loop / Midi Switcher + Midi expander

[Bumfluff101]

Rogue Squadron Switcher
I've build quite a few pedals now but I wanted a bit of a challenge so when I found this enclosure in a box of parts I thought this would be a nice longer-term project to get stuck into.


What is it
6 serial loops and two midi outs built across two PCBs. The audio board has a cornish-style buffer on input, feeding a chain of six dpdt relays for true-bypass loops. The logic board is an Arduino Nano driving the relays through a ULN2803A, with an MCP23017 reading the six footswitches and a Waveshare 0.96" OLED screen.



Features

• 6 presets, each storing the loop on/off state, a name, and 4 channels of outgoing MIDI Program Change + bypass CC
• Per-loop labels (3 chars under each loop box on the screen) — chosen from a list of 22 common pedal abbreviations (OD, DRV, DST, FZ, BST, CMP, MOD, CHR, FLG, PHS, etc.)
• Long-press Sw 1 to enter a latching preset audition mode — tap to scrub through presets, tap the loaded one again to commit
• Long-press any other switch in play mode to quick-save current loops to that slot
• Double-tap Sw 6 to mute
• A full editor with three pages (Name / MIDI / Labels) reachable by long-pressing a slot in the preset menu

The build
Not the easiest thing to do. The PCB design was fine, but for some reason I could not get the mount for the screen right. I think I 3D printed loads of different options and ended up going with a two parter, the main shell being screwed into the enclosure and a 'window' which locks it in tight. As you can see from some of the gut shots its a nest in there (and I wired the switches wrong and forgot the output jack ground) but its up and running and whisper quiet in operation. Because of how the Nano is fixed to the board, I used a GX12 connector to enable code updates without taking everything out.
Useability
Its not going to be used on a stage. The screen is small, the switches are to close together but for me it does what I want it to do. The midi is a bonus as I have a MicroPitch Delay and TriceraChorus which I can control via the presets. After starting the project I also purchased a HK Tubemeister 36 which has midi functions so I built an extra little midi box so I can control all three now.

This has been a really fun project and I'm really chuffed with it.







Quick video of some of the functions, trying to record the OLED screen was a challenge but you get the idea...

 

[jcpst]

This is awesome. And exciting to see someone pull off a diy programmable loop switcher. So clean, inside and out. I like your design choices for functionality. And the UI is fun with all those animated transitions.

I have been working on something very similar, off and on. 4 audio loops, MIDI I/O, programmable using an ATmega328. I’m not worried about the code. My hurdle is I haven’t learned how to use KiCad, or even how to draw a schematic on a computer instead of paper. So it’s going huge mess of connected strip-board pieces.

 

[phi1]

I really thought this was gonna be an audio looper that just plays the "Star Wars Theme" song. But this is cool too...

Just kidding, awesome job, that's really inspiring!

 

[Bricksnbeatles]

This goes hard. Great job!

 

[Bumfluff101]

This is awesome. And exciting to see someone pull off a diy programmable loop switcher. So clean, inside and out. I like your design choices for functionality. And the UI is fun with all those animated transitions.

I have been working on something very similar, off and on. 4 audio loops, MIDI I/O, programmable using an ATmega328. I’m not worried about the code. My hurdle is I haven’t learned how to use KiCad, or even how to draw a schematic on a computer instead of paper. So it’s going huge mess of connected strip-board pieces.

Yeah KiCad took me awhile to grip, I could draw the schematic out fine but trying to place components in some sort of order on the pcb took (and still takes) me ages to do. I end up getting cross and having to give it a couple of days before going back to it