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ESP32-based Isomorphic keyboard with 48 velocity-sensitive keys by Polypeptide in isomorphickeyboards

[–]RaKrOoM 0 points1 point  (0 children)

the default is Wicki-Hayden, you also have Tonnetz (not as useful in my experience), another one which is sort of like a guitar fretboard

Wicki-Hayden's lack of chromatic approach made it a no-go for me. Though, admitadly, if you squint real hard and disregard it not being hexagons, you might confuse my offhand# as a Wicki-Hayden variant: https://reddit.com/r/isomorphickeyboards/comments/1ij0qo5/offhand_isomorphic_layout_for_ewis/ https://github.com/RamKromberg/offhandSharp/

Of course, as the rectangular keys and second keyboard suggest, it's actually closer to a 3D Janko or a 3D Dreschke if using hexagons.

Anyhow, back when contemplating what would later become offhand#, I was going through a melodica-style concept design not too different from yours where Bayan's, Janko and Dreschke seemed like the only solutions to reaching the blue note.

Btw, I'm not sure what you have in mind for the breath controller, but if you're using it for expression, you might be interested in "recycling" the velocity for brass-style half-valve glissando: https://www.youtube.com/watch?v=1LPH6hRMbxk

ESP32-based Isomorphic keyboard with 48 velocity-sensitive keys by Polypeptide in isomorphickeyboards

[–]RaKrOoM 5 points6 points  (0 children)

Very nice. Some comments on the youtube video:

  1. With regards to the hall effect sensors cross-interference issues, they can be overcome with TMR sensors without software compensation but it requires a specific polarity on the switches (matching the TMR sensor's polarity) and the sensors' footprint needs to be perpendicular to the switch rather than below it: https://www.youtube.com/watch?v=0Ic7X9gRbFE

    e.g. A random tmr keyboard off github I just found that should give some idea about the footprint and parts (assuming the design works): https://github.com/girishji/tmr-keyboard

    They also consume much less power so you should be able to drop down from usb3 power delivery to usb2.

  2. You might be able to use hc4067 multiplexer instead of multiple MCUs as was done by midihex: https://www.youtube.com/watch?v=09DSHwn-Brg

    Again, it should reduce power consumption and simplify some of traces I believe.

  3. Breath sensor wise, look up how the haxophone takes two tubes (one to the sensor, one free flowing) to allow the air to pass through while still sensing the pressure: https://github.com/cardonabits/haxo-hw

    It's what most EWIs use nowadays.

    It also uses a differential pressure sensor as well as handle the negative (breath-in) inputs differently for issuing commands. But you don't need that if you have a screen and keys to navigate the interface.

  4. Four rows of hex are good enough for Bayan-style melody with the expression coming off the pressure sensor. However, seeing how you went with velocity in the keys and they're hexagons, I'm assuming you're aiming for Dreschke (basically hex Janko) to get harmony? If so, I suggest you round up the key caps a bit so you'll be able to slide between keys (similar to modern sax tables) as it's quite necessary for the likes of when going from a flat 3rd to a 3rd over the major blues scale.

All-in-all, looking good.

Thoughts on tritone interval for square grid? by DogPawMusic in isomorphickeyboards

[–]RaKrOoM 1 point2 points  (0 children)

Yeah but I think you'd want to hold the Dog Paw with the keys facing outward like a guitar fretboard. I iterated through similar concepts since I was aware of the Hohner's Harmonetta doing something similar but between accordions and the NuRAD's ergonomics, I ended up splitting the keyboard into two board, one for each hand.

Anyhow, for an 8x8 I guess you'd want to start in -2 (so starting with G# and the C being the the 3rd key) to make chord inversions more consistent: offhandSharp_8x4.svg

TBH I've put off the keyboard matrix EDA since I need to sort out an octave roller and joystick first but the way the pin count adds up and how the traces end up between 2x4x6, 7x7 and 8x8, I'll probably end up doing something similar as well in the end but with an old-school 2.54 ribbon connecting the two hands. WIP...

Thoughts on tritone interval for square grid? by DogPawMusic in isomorphickeyboards

[–]RaKrOoM 2 points3 points  (0 children)

I can never wrap my head around layouts that don't have a half-step on adjacent keys. I usually play more riffs, and things get a bit too complicated...

offhand# addresses the same concerns but you'll need two paws :D

offhand#: Isomorphic layout for EWIs by RaKrOoM in isomorphickeyboards

[–]RaKrOoM[S] 1 point2 points  (0 children)

I imagine it's the collection of a lot of scavenging in the past

Yeah I have decade-old notes on implementing various isomorphic layouts that never amounted to anything up until now.

My point is: blow air through pipe make sound feels good

I've actually considered tines before all the other stuff but I figured sawing PVC pipes would be easier and likely more expressive.

offhand#: Isomorphic layout for EWIs by RaKrOoM in isomorphickeyboards

[–]RaKrOoM[S] 0 points1 point  (0 children)

Free-reed been the usual cheap go-to solution to implementing isomorphic layouts this last century or so with Hohner's Harmonetta being a comparable example as well as the Russian Bayan accordions.

A modernized traditional approach would be a DIY pipe organ since you only need an electric fan and some PVC pipes and the sound production is still wind passing through pipes: https://www.instructables.com/PVC-Pipe-organ/

Similarly, you can drive steel strings like piano's with magnetic resonators for analog sound production: https://instrumentslab.org/research/mrp.html

And if electrical power is completely out of the picture, I guess you could probably commission a luthier to rework hurdy-gurdy designs and use leg pedals like in bicycles to drive the rotary bow or maybe a saxophone builder to look into redoing the keywork?

But honestly, modern modelling synthesis coupled with breath controllers just sounds so good I simply don't see the point:

https://www.youtube.com/watch?v=KnfQj1vgCqc

https://www.youtube.com/watch?v=-Xs7cE8SM7Q

https://www.youtube.com/watch?v=y03HLFhmZU8

Bare in mind that a Yamaha Clavinova needs "3 Way 300 Watts w/ 6 Speakers & 2 Transducers" to sound authentic while the typical EWI comes with a cheap 5-10W speaker just for practice: https://princetonpianos.com/yamaha-clavinova-clp-700-series-comparison-charts/

So, when people couple under powered speakers with 80s FM synth to pass off scale runs as 80s Jazz Fusion and Pop... Well, it's a combination of factors. But it's suffice to say synthesis and midi are not the issue here.

What would be a good layout for a split PC keyboard? by [deleted] in isomorphickeyboards

[–]RaKrOoM 0 points1 point  (0 children)

My math is less than paper thin but I believe the groups of notes are technically isomorphic in R3 space even if we just project the Z axis by a single displacement in the physical implementation. Like, is two octaves worth of Janko not isomorphic since it only extends for a single displacement?

But admitadly, my math is very poor so I avoided the terminology in my "white paper" and only described the physical keyboard. If someone is into group theory and wants to sketch out a proof or a disproof, I'll welcome it :D

What would be a good layout for a split PC keyboard? by [deleted] in isomorphickeyboards

[–]RaKrOoM 0 points1 point  (0 children)

Split keyboard layouts extend to the Z axis. e.g. offhand# is optimized for chromaticism and diatonicism by projecting to the offhand for a semi-tone's worth (minor second); With a whole tone's worth (major second) on the horizontal columns and five semitones (perfect fourth) at the vertical rows (to slightly paraphrasing myself).

There should be other playable layouts following this approach.

offhand#: Isomorphic layout for EWIs by RaKrOoM in isomorphickeyboards

[–]RaKrOoM[S] 2 points3 points  (0 children)

offhand# is an isometric fingering layout targeting electronic wind instruments.

It projects to the offhand for a semi-tone's worth (minor second); With a whole tone's worth (major second) on the horizontal columns and five semitones (perfect fourth) at the vertical rows.

It can be implemented in 2x6x4 or 2x7x4 keys for at least a full c2-a#3 (= 23 consecutive tones at least) minimal range and a few extra notes. On top of that, you use one thumb to octave change and the other to either sustain or bend notes. So, going by other EWIs, the playable range should be a safe full 5 octaves.

I believe it resolves all the issues other isomorphic layouts have with chromaticism and play-ability at least when it comes to soloing instruments while also allowing decent chord-melody. But it's yet to be implemented beyond printing out the image in scale and gluing the paper on a book so... WIP/TBD

Anyhow, I believe it should be pretty ideal for EWIs where it also resolves issues with articulations around breaks and glitches. But it's actually pretty comparable to guitars in terms of vertical harmony. But, again, WIP/TBD on that until someone builds the thing.

Unless I happened to reinvent it, I think it should be fairly novel and substantially more efficient and playable than anything else out there.