Midihex project (Axis-49 clone)

[BJG145]

I finally made it down to Norwich Hackspace yesterday to have a go at laser-cutting a keyboard plate for my Midihex on 1.5mm acrylic. I've realised this is high precision stuff, and adding just 1mm across the width of the 330mm plate, as the Greyfin A2 seemed to do, is enough to throw things out so that the keys aren't seated correctly on the PCB.

Fun trying though. I'll be back for another go soon, but with these acrylic sheets costing £10 a pop I'll stick to cardboard for now.









Laser cut (YouTube)

[_jesskimo]

Sooooo interested in this project. Would you consider selling these if you were happy with the outcome? If so, SIGN ME UP!

[BJG145]

Thanks for the encouragement, planning to run off a few of these when the case is done.

(I'm going to try using a PCB for the top plate instead, which seems to be a popular approach.)

[ajay_m]

If you don't need the top plate to be transparent you can 3d print it. To get a mirror surface you print to the smooth side of the build plate. I've done this for the sequencer project I'm working on. Black PLA looks very nice this way. Infill with the lightning pattern to avoid internal stresses that'll warp the plate during printing.

[BJG145]

Someone suggested using a PCB as a keyboard plate. I just received a set of these from JLCPCB and it works great. Just the case to do now.



(Regular keyswitches are soldered in place, but this design is based on Lekker Hall-effect keys in order to generate velocity data. These have a pair of plastic lugs which drop into the PCB, but you need a separate keyboard plate to make a sandwich that holds them in place.)

[Lostgallifreyan]

I don't understand it, but it's beautiful work! It makes me wonder what the game rules are, how to turn things over to dominate the board.

[BJG145]

Initial case design from the man in Japan...been genning up on heat set inserts.

[The Elf]

I'm in awe of this. Software? Doddle. Hardware - aargh! Been there, bodged that.

Anyone that can create something of this finesse... damned impressive.

[BJG145]

Thanks Elf...

I see there's a new mini MIDI keypad coming out based on the Lekker L60s. Since I've been posting enthusiastically about the concept online for the past 18 months and no-one's released anything like that yet, I'm gonna claim a little of the inspiration behind that. It's like my test board on steroids.





https://unwn.dev/shop/midi-controllers/topo-t16

Just ordered a case from JLCPCB. £75 just for the bottom tray...ouch. I'm not ready to scale up to injection moulding but I'll have to find something more economical than that.

[BJG145]

First version of the case, also known as the "Frost" model.

[resistorman]

Nice! What are the dimensions?

[BJG145]

It's a chunky 34x21x4cm. V2 needs some curves...

I thought I'd enter it in the Midi Innovation Awards prototypes category, so I need to work on a demo next. It feels more tempting to practice now. I'd ask Jordan but he might break it.

https://youtu.be/d8CO4scqQ9o?t=419

[BJG145]

Currently working on v2 of the case, but there's an aspect of the construction that I can't get my head round, which is what combination of screws/spacers/standoffs to use in order to ensure that:

- The PCB and keyboard plate are securely fastened together
- The bezel is screwed down to the correct height, flush with the top of the case

Any thoughts welcome.

(The "heat-set inserts" for the mounting posts in the last design didn't work, since it's printed with resin, and that doesn't melt; it crumbles. So we're going to try "nut traps" for v2; also experiment with some simple bevelling and graphics.)

https://markforged.com/resources/blog/e ... d-printing

I'm also trying to get a better understanding of MPE in order to take advantage of the full-range positional info returned by these hall-effect keys. This should make it possible to implement a Polybrute-12-like response instead of simple velocity.

https://www.arturia.com/products/hardwa ... 12/details

[ajay_m]

Threaded brass inserts work well with 3d printed cases, I've used them in several designs. You do not however heat insert them but use epoxy to hold them. Using longer screws than the final mounting acrews, ensure each insert fits in the mounting pillar and then screw the insert flush to the end of the screw. Then dab epoxy round the outside of the insert and press it firmly into the mounting pillar hole. You then wait until the epoxy has mostly set, unscrew the temporary screw and use a sharp knife to remove any excess epoxy that has spilled over the top of the pillar.

I'd also note that mounting pillars generally need a base strengthener consisting of a 1mm or so high circular feature at the pillar base and about 2mm or so larger in radius than the pillar base. Otherwise the pillars have a distressing tendency to shear off during assembly.

[BJG145]

Thanks for the info!

[BJG145]

...v2 of the case, that assembles from the base. (Uses nut traps.)





No luck in the 2024 MIDI Innovation Awards prototypes. But...two out of three were accordions? Really?

https://midi.org/innovation-awards

[BJG145]

Entering the MIDI Innovation Awards did at least get me invited to a live stream with Gustavo Silveira, aka Nerd Musician.

https://youtu.be/09DSHwn-Brg

I'm posting this partly for completionists who are obsessing about this amazing new instrument...



...and partly because I was reflecting on the experience more generally; but I'll post that in the ML.

[Drew Stephenson]

Entering the MIDI Innovation Awards did at least get me invited to a live stream with Gustavo Silveira, aka Nerd Musician.

[BJG145]

Midihex #3 - Liquorice Cream.



I've been agonising about what I could use as an internal soundcard for this for ages. I've narrowed it down to two...Ksoloti, or Daisy Seed.

Daisy Seed is potentially cheaper...£31 on Thonk, as opposed to £56 for Ksoloti, but pretty difficult to learn. There's a couple of companies that offer PCB/Github/tutorials though, and one of them is Synthux.

https://www.thonk.co.uk/shop/synthux-si ... uch-2-kit/

Just one problem...I hate soldering.

While I was trying to make up my mind, a fully-assembled Synthux Touch appeared on eBay. What are the odds?



Bought. Wish me luck.

[resistorman]

All these great operating environments, I wish I was 50 years younger I bought a Gills for Ksoloti and managed to get a fun efx setup going in spite of my rudimentary programming skills, but it's somewhat vulnerable to the USB power/ audio noise problems that plague these devices. Good luck on the Synthux

[BJG145]

A couple of days ago I received a new batch of PCBs.



These now have a MIDI pin header for connecting to the Daisy Bud. (Thanks James/Folderol.)



I spent the day putting together a new embedded-audio version, and it works great. Happy with that. The theory is that now I've got a portable self-contained one, I'll be more likely to learn to actually play the thing.

[BJG145]

Currently waiting for a new PCB for the "Axis 64" version to arrive from JLCPCB. Fingers crossed...



I was looking at the patent for the Lumatone yesterday and finally found that angle that merlyn & co correctly figured out officially documented. If this one works, that's next...!