Did you consider that those keys aren't actually what it says on
the labels because one-off keyboards with more than 100% of the
standard layout have keys that no correct labeling exists for?
I'm gonna build one! Ordered two boards immediately. Qmk orthogonal keyboards are trivial to add MIDI to and super fun, I've made a few. I already have the switches. Grand piano range with a bass guitar layout
For some context, this project was basically made to one up someone else, so it's not fully serious. Part of what makes the keyboard funny though is that (a niche of) the custom mechanical keyboard scene has been moving to many fewer keys and programming the firmware to compensate. So it's pretty funny going from seeing several Planck ~49 key layouts to seeing this gargantuan 450 key absolute unit.
Is it an Atreus? How do you like that size of keyboard? I'm not too bothered about adopting some chords, but more interested in the general ergonomics / RSI risks.
I am not OP, but I moved to a 40% (44 key minivan) about a year ago, and I am using it as my daily driver at home and work. I find that the fact that I can reach every key on the board and barely move my hands has helped a lot. The other interesting notation is that I can put the mouse really, really close by. So the motion going from keyboard to mouse is greatly reduced. I find that my wrists are much better off with this.
That's helpful, I think the space and movement is definitely an issue w/ my RSI, but I have a feeling the chords might end up taking over if I swap out, but may give it a shot :)
What sort of WPM did you have on normal keyboards, and whta have you been able to train up to on your current one? I plateaued at roughly 35 WPM on Dvorak as a teenager and have been hesitant to commit to major layout changes since then, despite the ergonomic promises that a lot of them make.
I am the minivan owner... I find that my WPM did not move significantly. In fact, I would argue that for the most part my typing speed is the same. Now, when it gets to coding, or {}, [], things slow down just a tiny bit, but with todays editors, this can be minimized.
I will admit, I have been in IT for many years. I feel like unless you are an accountant, or someone that has to hit {} [] constantly and can not deal with macros, that the 60%, 40% keyboards help a lot. Most CS/sysadmin/engineer type people are good with layering anyway.
I will say this, on a normal keyboard, you have to hit shift to do a few odds and ends. On a 40%, you would be amazed at the speed that you pikcup "oh, hey, {} and [] are over here, just I have to hold down this one key, just like shifting on an normal keyboard... ok, I get it" and then by week two you no longer think about it. Just my $0.02. I did, however, test my typing speed on one of those online things. I really did not change much after about a month from my previous keyboard to the minivan.
I definitely agree with you here, I like split ortho a lot (I'm typing this on an ergodox) but I'm super doubtful of any benefit for non-split orthos. My arms don't sprout from the center of my chest!
I actually prefer non-split orthos but with a split layout. What
I mean with that is something similar to split keyboards but
angled and within one case. This is still very ergonomic but
more portable. Combined with columnar stagger and reduced to
about 42 keys I find it extremely comfortable to type on.
Oh yeah, when I say non-split I mean fully rectangular layouts where the left and right hands are perfectly parallel. If you have clearly separated left and right sides that counts as split for me, even if they're within the same case.
That being said obviously you have more flexibility if you have fully separated sides, but it does tend to make the keyboard harder to carry around.
That reminds me, I consider losing arrow keys a dealbreaker. I use them frequently enough to navigate both text and code in various contexts (except in Vim, which I don't use exclusively). I already hold modifiers to jump to next/prev word boundary, page, start/end of continuous data ranges in Excel, etc. Admittedly, I'd probably adapt, but I'm held back by the belief that any ergonomic advantages of moving to wasd or hjkl would be wiped out by reduction in speed and muscle memory for me.
I had similar misgivings, so I chose an ErgoDash, which has a few more keys than some of the minimalist offerings. I have the arrow keys in a horizontal row (which took some time to adapt to), but I can still use them with Alt/Ctrl/Shift modifiers fairly easily.
However, I'm planning on making something like this[1] "trackball Dactyl Manuform", where the trackball under the thumb can be configured to use different modes -- e.g. a key toggles it between being a mouse and being arrow keys, and another locks it to vertical/horizontal. It could be combined with holding Alt/Ctrl/Shift.
I made a gallery of split/ergonomic mechanical keyboards if you'd like a quick overview of other options. [2]
Do you happen to have an opinion on the best split keyboard for someone who uses and likes a Kinesis Advantage but would like a more portable alternative?
Or even suggestions on what I'd need to google to find opinions of people in that group?
Anything 3D/dished like the Advantage isn't going to be very portable, just because of the bulk. I suspect many DIY versions are also fairly delicate, as a result of the 3D printing process.
For a flat, split keyboard you could look for one where someone has already designed a case that goes some way to protecting the keys, or make such a case yourself. I wouldn't choose something with this few keys, but [2] is on the first page of the Reddit, and shows what I mean -- unlike the keyboards where the "case" is just a sheet of acrylic, this one looks like it would be OK stuffed in a bag. Many of these keyboards use a Pro Micro controller, which is known to have a weak USB port. Using a wireless keyboard, or choosing a different controller, might also help.
You will have far more options if you're able to solder the components onto the PCB yourself. Otherwise, there are a few companies like falba.tech that sell assembled keyboards.
HHKB has worked well for me, it moves the arrow keys closer to your right hand in a much better location than most 60% boards default.
You can easily use your right pinky to hit Fn and then use the arrow keys that are right under your fingers (I think it's actually better than normal keyboard arrow key placement).
I don't think I could go below a 60% board because having the number row is too useful and dealing with function layers for that (and memorizing symbol placement) seems like an unnecessary pain for style.
With light switches and a compact layout it's not too bad for navigation. My default for arrows is LeftThumb+HJKL, so it's quicker and more natural then diving for the arrow keys. I also have overloaded alphas (Ctrl on a or ;, Shift on Z/?, etc) so Ctrl-Shift-Up maps to A+Z+LeftThumb+K. Seems a little bonkers but it only took a few days to adjust to my GergoPlex [0][1]
The bigger issue with adding more keys to the mix is that with heavier switches (35g+) the amount of work/stress done by the hand can be more then a traditional keyboard. But even with heavier switches it's often faster then having to move your hands around the physical board. And once you factor in things like combos you can just map End to something like QW or whatever works for you. Programmable input devices are _really_ weird!
I don't have arrow keys on my board but I have something better: I have a special modifier that lets me use readline-style commands (C-n for down, C-p for up, C-h for backspace, C-d for delete etc...) anywhere without requiring the app to support it, since it sends the compatible down/up/backspace/delete/... keycode instead.
I finally don't have to worry about this or that program not supporting this or that binding, it's uniform everywhere.
You say that you already use hjkl (I assume?) in Vim, so clearly you have the muscle memory for that, why not extend it to all applications?
And there's so much more to programmable keyboards. Modifier keys that input characters when pressed on their own, allowing for dual function. Some people like remapping caps lock to control, others to escape. Why not both? My keyboard has a key that behaves like control when chorded and like escape when pressed on its own. The best of both worlds!
A DIY custom actually![1] It's a split with 3 x 6 alphas, 3 thumb keys, and a palm key. I really like it but I was already moving in the direction on layout-minimalism on my ErgoDox. You can find a pic of my layout here[2]. Happy to answer any questions about it.
On ergonomics and RSI, tough to say whether some of these things make a difference or not. There's no data. The single biggest difference to me is having multiple thumb keys because that allows you to almost completely relieve the pinkies. The only sideways movement I use them for now is a "sticky keys" style one-shot modifier for Control on the keys adjacent to the home-row. Although having a split board (and standing desk) has been super for overall posture.
In Vim, I would love to be able to map Ctrl-[ (which is what I use instead of Esc to change modes) to Ctrl-thumbkey just to relieve the right pinky. I'm using a standard mechanical TKL layout now. Or maybe just map Esc to a single thumb key.
Yeah as a heavy vimmer I also used Ctrl-[ with Caps-as-Ctrl for the longest time on a regular full-sized keyboard. Esc is great to have on a thumb key though. I used it on one of the outer ones on my ErgoDox and it worked well. A nice vim quality of life improvement was programming keyboard macros for `Esc : w Enter` and for quit.
It's not new in the vim world, but now what I use is `jk` pressed at the same time. Adjacent finger pairs are pretty easy to coordinate fast combos with -- just sort of jab your hand. Since it's in the keyboard firmware (QMK) it works in all contexts and not just vim, but the `jk` combo is also something that I can configure in the vimrc to use on my laptop.
Also not autocorr but I've had tons of fun with my Ergodox EZ. The layout relies on using the thumbs to chord layers, right now there's 6 (I actually started running out of useful codes/actions to put into slots, need to get into macros next). the 30 keys in the home row and above/below plus thumbs see heavy usage.
Thumbs do L3, space, L1, escape, L2, L4, control.
L0: dvorak
L1: programmer, left hand symbols (all 4 braces paired under middle and index), right hand arrow keys, nav, pgup/pgdn. Vimlike navigation at the keyboard level!
L2: left hand function keys, right hand numpad
L3: qwerty layout but with command so I get natural one-hand undo/cut/copy/paste
L4: mouse keys. Not a big fan of mouse nav, but keyboard issuing scroll up/down is handy
L1+L2: macros live here, I use this to eg. flip between iterm tabs. I desperately need more bucky/control bits though - It's hard to know which hotkeys are mapped across various applications. Give me a real Meta key, dangit!
This lets me rarely move from home position and it's great for ergonomics. Still trying to figure out what to about the mouse, as that makes my hand cramp. I keep a magic trackpad between the ergodox halves for gestures which is neat. But the dang mouse. Maybe it's the way my brain works, but I'm rarely in a single context, flipping between Pycharm and chrome and terminal constantly. Controlling application focus is a pain point.
I can't do the vim thing. I've tried for years. I'm a fast yet inaccurate typer, and the lack of any insight into the state (other than mode), and the heavy chording setup means spooky action constantly happens. I also hate having to hit a key for mode changes, chording is so much more efficient.
I use bettertouchtool and alfred, and don't have a lot of customization in there, so if anyone has any tips for utilizing this sort of setup to reduce mouse reliance, I'm all ears.
And they even have keys (modifier keys?) for their feet. They left that off the table (so to speak)
hmm... and maybe some sort of suspension system for your arms, so your arms could float over the keyboard sort of like monitor arms keep your monitor suspended in place but allow movement.
Or if you want just some minor additions, try Sun Oracle Type-7 keyboard which has ~10 keys (including Copy, Paste, Undo, Cut - perfect for Stackoverflow-oriented programming) on the left
wow, brings back memories. I never had an oracle version though. I remember being very happy when sun came out with a USB version of their keyboard so I could use it elsewhere. (previous versions had a sun connector)
It's sort of like when people see emacs next to something like sublime text on a mac. It's probably super-capable but being a prototype it lacks the polish of a finished product (while overshadowing what it can do)
I regularly use what I call a "140% keyboard" which has a total of 140 keys. This is the regular 104-key layout with added keys in various places such as between the alphanumeric and F key section, filling the gaps between cursor keys and the block above it, etc. The keyboard has on-board macro programming and multi-layer logic.
I use it for things like having keys which jump directly to specific windows, keys which open various terminal types, and even macros for some common commands (Git operations for example).
I don't know that there's any good reason why this isn't more popular other than fashion, which means that an industry has not really built up around plus-sized keyboards like it has around smaller ones. My example was purchased used and was formerly used at a telephone operator's workstation, based on the key legends. There is a fairly robust used market for plus-sized keyboards originally used for specialty applications, mostly POS and dispatchers/radio operators, from companies like PrehKeyTec and Cherry (of the switches). Unfortunately they mostly cost $500+ new and still often demand over $100 used. The majority of these keyboards feature on-board macro programming, but are intended to be programmed in bulk by the vendor of some turnkey solution so the programming tools are a bit awkward (for me, use a GUI keymap editor, export a file, use a command line tool to flash the generated file to the keyboard - I think it actually just produces a full firmware image each time).
The only real disadvantage I would report is that the PrehKeyTecs are made with dome switches that feel decidedly mushy when they're old (and my used model is probably around a decade old). The Cherries use mechanical switches, of course, but tend to be more expensive and aren't made in as interesting of configurations IMO.
Do you happen to have a picture of the layout? I too wish for a keyboard with more keys, especially vertically. But besides an extra row or two of F-keys, I haven't come up with any logical extensions.
Note the blanks in the lower right there do have switches under them so you could put keys there as well (that's where mine has Hold and UnHold incidentally). One warning is that the blank keycaps and relegendable keycaps (the ones that are a clear plastic cover you can stick a bit of paper under) are mostly sold in bulk to system integrators and it's expensive to get them in small quantities. So if you're in the market, you probably want one with as many of those as possible. PrehKeyTec's software supports printing legends for them but it's pretty basic so you might want to use something else to design them.
This is pretty interesting, but it'd be great if the author explained their reason for building such a large keyboard... even if it's just "for reasons".
this was also posted on r/MechanicalKeyboards and the reason behind it was something like “I made a 128 keys keyboard, someone else made a bigger keyboard so I had to retaliate”
That's exactly why I made Ginny (the small red keyboard in OP)! It's an exercise in insanity, but it does work as a fully functional keyboard powered by ASETNOIP. I could never daily it (too attached to my 36key GergoPlex) but some users are above 130WPM on 10keys!
agreed, immediately closed, not sure why they bother with writing something if obviously they don't care if anyone reads it with choosing font/effect like this
1) For some reason this thing gives me joy. Imagine sitting at work in front of one of these bad boy keyboards! You'd never get interrupted! People would assume you're running a battleship remotely or something!
2) It seems very Soviet. Or at least very 80s Anime - this is the keyboard we should all be using, only each key should light up in disco colors.
That's a surprise. I was expecting keys 433% as large as ordinary ones. It could be for a person who types with feet, arm stumps, or elbows. It could be for a person in protective gear. It could be for a trained animal. It could be for entertainment, such as by hitting the keys from a distance to win a carnival prize.
There are a limited number of scancodes; defined by the USB standard. The annoying thing for keyboards is that the OS controls what scancode maps to what character and that makes it impossible to have certain keys.
For example, you can't have an ! key. That is always Shift+1 (with a US layout, that is). QMK and other firmwares will let you make an ! key, but it's implemented by pressing shift, then pressing 1. So you could never make a keyboard shortcut that is Shift+! even though you can press that on your keyboard. The OS wouldn't be able to tell the difference between than and Shift+1. As a corollary, you couldn't rebind your keyboard such that Shift+1 outputs @ instead of !.
It's really just a classic case of bad abstraction. All the keyboard hardware does is scan rows and see which columns are also active. That gives you a grid position like (1,2) for "w". It is then forced to translate that to a scancode that it sends to the computer. The computer then sees that scancode and translates it to a letter. Obviously, things would be easier to program if the keyboard just emitted characters, or the OS just read key matrix grid positions. (In the first case, your X key would always be X, no matter what. Annoying for laptop users that want to use Dvorak, of course. In the second case, things like QMK wouldn't need to exist, you could just write a normal program running on your computer to add layers, shifting, tap dances, etc.)
The end result is that everything sucks. Isn't it always?
I know that was probably just meant as an illustration, but you can have an ‘!’ key — it's 07:00CF “Keypad !”¹.
Linux will ignore it² though, because being Linux they had to NIH their own key codes, and Windows will ignore it³ because it wasn't on the IBM PC keyboard in 1981.
Stepping back, why would you actually want the keyboard firmware to have configurable settings and runtime state? xkbcomp (Linux/Xorg) is buggy as hell, but I'd say it's still fundamentally the right abstraction to do this on the host. Configuring a layout on the keyboard is itself the hack, really only encouraged by the recent innovation happening there.
It's been a hack for years, not merely recently. Maltron keyboards used to switch layouts between the "PC" and "Maltron" layouts by the keyboard moving scancodes around, in response to a physical switch at the back of the keyboard, back in the days of PS/2 keyboards.
I've thought about this a lot, because I've bumped up against that limitation a few times when customizing my Erogodox layout.
My conclusion: QMK could do this, or at least some firmware could do this. It's hard to come up with an eloquent way to express it, however.
But there's no a priori reason that pressing shift-1 couldn't be special-cased to instead send shift-2, yielding @. It's all being precomposed by the firmware, after all.
It's too bad, because I have a custom key for delete-back-word, and I want shift-thatkey to send delete-forward-word, but as you point out, I can't. But that's a limitation of QMK, not a fact of nature.
You can write code to do that in your process_record_user hook, but it's probably going to be flaky. I would just use a modifier other than shift; people tend to call them "raise" and "lower" and just change the layer. That way everything is in control of QMK.
The disadvantage of using layers is that you can't press the layer-activate key on one keyboard and then press your key on another keyboard. With shift (and OS-level modifiers) you could technically do that. But it's a weird case that probably doesn't come up very often.
Reading https://news.ycombinator.com/item?id=24497839, there’s a keycap gap. “They” have more keys than “us”, so we must get even more, even though we already have more than we will ever need.
Hate to be that person, but I'm surprised people like mech keyboards. I ordered one, hated it so much, I actually decided to return it. Too loud, too much force required to type. My ideal keyboard is the low-profile laptop keyboard, especially the thinkpad one, the one before chiclet keys became a fad.
This is perfectly understandable—mechanical keyboards are certainly not for everyone. I’m in the same boat but for slightly different reasons (and my ideal keyboards are the ThinkPad one you described and the desktop Apple Magic Keyboard, which has a really satisfying key feel).
I think a lot of people in the mechanical keyboard community think of their keyboards as a hobby just as much as a day-to-day tool. The huge variety of key-switches and keycaps and firmwares and the much greater customization opportunities make mechanical keyboards a very good hobby. And, given the variety, it’s probably possible to find the “perfect” keyboard for everyone.
In the end, I was convincing myself that the expensive mechanical keyboard I bought was better than my ThinkPad and Mac keyboards, when I actually still prefer the laptop-style keys. Is there a mech keyboard out there somewhere that would be the perfect fit for me? I’m sure. But I don’t want to spend the time and money searching for it when my current preferred models work plenty well for me. I’d rather spend my resources in other ways.
There's certainly not just one type of mechanical keyboard. If noise is a problem, you likely had clicky switches or just a really noisy plate / keycaps. Yes, keycaps actually really determine a lot of the noise profile. XDA/DSA keycaps are pretty quiet.
Travel distance can also be adjusted, either with o-rings that are used as spacers (that also silence the switch), low profile switches (kailh has laptop-sized switches now) or simply finding a switch on which you wouldn't bottom out (either by making them heavier or by using tactiles with a light bump).
I have a 60% board with gateron yellows (mid-weight tier linear switches). Lubed and with double o-rings on the keycaps, it's one of the quietest keyboards I've ever owned, and the travel distance is very comfortable at about half of what these switches are intended to be (around 2mm).
If you're not much for building these things yourself and doing all the research, I can always recommend the HHKB.
There are different kinds of mechanical switches. Some of them much lighter than a typical membrane keyboard, so light in fact that you may accidentally press keys without realizing it. As for noisy keyboards, again, some switches can be noisy by design but others are silent.
As for profile, the ThinkPad keyboard is rather high profile for a laptop. I don't know of any low-profile mechanical keyboard but some switches have a short travel distance, ideal for gaming and fast typing.
BTW, the ThinkPad keyboard is available standalone if you like it. You may need to buy it secondhand if you want the original though.
This keyboard is clearly silly, but when it comes to normal mechanical keyboards... well, I can barely live without it now. Volume and necessary force do vary though, so what I like might not be very similar to what you didn't like.
I used to think this, but recently using a friend's long travel keyboard made me doubt my position - I typed unexpectedly quickly without any getting used to it. I suppose I'll have to try it out a bit more, but it was definitely pretty surprising to me.
To be honest I love "mech keyboards" not really because of the mechanical keys, but because people make them in so many customized sizes and colors. But there's not really a good term for this as far as I'm aware.
> Why are there >3 rows of Fn keys ? Are they all different? Or Are they placed so to quickly access ?
It looks like the creator just used whatever random keycaps he had. There are also duplicate arrow keys and duplicates from the navigation cluster (e.g. pgdown). The katakana(?) keys also look like they might be incomplete.
I know that at least Linux does support additional F keys beyond F12, since there used to be computers/keyboards that had them. I'm not sure how having more than 255 keys works out, though, I haven't looked into how USB HID handles it.
There's enough for 65535 different usages in the keyboard page alone, and there are more available in the consumer and system pages. But nowhere near all of those have definitions.
There are defined usages for function keys up to F24, and for all of the dedicated function keys that one could find on Sun and IBM keyboards, such as Stop, Again, ExSel, and CrSel.
While were on the topic of keyboards, does anyone know of a good nkro keyboard that's small? I want something to lay on top of my dell xps 13 while I use it that's nkro.
I have an old IBM F122. A 122-key keyboard is pretty much peak keyboard when it comes to easily purchased commercial offerings. The smaller less sturdy sibling of the F122, the M122 (yes, M as in model M) can still be purchased relatively easy, but then you lose about a kilo of weight, nicer switches and N-key rollover. The prices for model F keyboards are bonkers today though.
Your option when it comes to a lot of keys (as the one posted here) is either to build it yourself or try to find some very specific offerings, maybe aimed at video production.
It's fairly easy to buy a "multimedia" European keyboard with 124 keys. It's somewhat harder, outwith Brazil, to get hold of a "multimidia" ABNT2 keyboard with 126 or more keys, but they are commercially available there, at least.
Of course! I was never a fan of those flimsy hard plastic keys, so I didn't include them in the peak keyboard. This is more my taste: https://i.redd.it/hkb7kvqpob431.jpg
There is a guy making "new" model F keyboards out there, and if he ever makes an f122 clone I will probably buy it, regardless of price.
Look out for PS2 and a hard requirement to program them via a real PS2 (not a USB emulated port).
I've bought one (cherry switches sans keycaps), filled it with blank keycaps and now I need to put together some electronics to make it useful (it looks like it uses something like SPI internally).
But first, I'm stuck trying to remember why I thought it would be cool. Because it's just an 8x16 grid of switches.
At least that hybrid model with QWERTY has aplausable use case. But mine is just a grid. As for mine, there's only so many shortcuts you can assign to 128 anonymous keys...
As a Tunisian (north africa) I write mixed texts containing both arabic and latin scripts. I have an azerty/arabic keyboard, arabic letters are on the same keys as latin letters so I constantly need to switch layout when I'm typing. A ~200ish keys keyboard would be Ideal for me. And i suppose it's the same for all non-latin keyboards
> Even Latin, if you use enough languages with enough diacriticals. Or want to code in APL. Or use Greek letters when typing math.
I've always wanted something like the space cadet keyboard with a couple of extra modifier keys vs. what's typically available today for typing unusual characters (and the keycaps for making that easy).
That's pretty straightforward to DIY with the TMK firmware. Or even just with Autohotkey and your existing board; pick a key you don't use much (Caps Lock, right-Win, etc) and make it one of your meta keys.
Print your own keycap labels with Avery sheets for starters, and once you've got the layout nailed down, you can send off to have custom caps made by whatever process you like.
Only 3 extra modifiers, really (a PC keyboard having 4, discounting left and right variants) and fewer actual keys (a mere 100) than an old U.S. 101-key Model M keyboard, let alone a modern U.S. 104-key Windows keyboard.
Keyboard maps are on the host, not on the keyboard. Engravings on the keytops are meaningless and are not what determine how a key is understood. A (for example) U.K. 105-key keyboard and a French 105-key keyboard just look like two 105-key keyboards with all the same keys to the host.
Several common operating systems just combine all keyboard input from multiple plugged-in keyboards into one giant "union" keyboard and apply a single keyboard map to it.
I've been working on Linux/BSD software that allows individual different keyboard maps per keyboard, for my user-space virtual terminal system. It's achievable, but I've not encountered anyone else who has seriously attempted to make such a thing work, in the general case where arbitrary USB keyboards can be plugged in and out at runtime.
You're right, I haven't tried this. But my (unmentioned) approach was going to include using at least one fully programmable keyboard -- QMK or similar -- to send precisely the keycodes wanted.
It doesn't work that way. The USB HID usages (and PS/2 scancodes) are the same. There is one usage for the key at (say) D01, and the keyboard doesn't know or control whether it is "Q" or "A" or something else entirely. You cannot switch layouts on the keyboard, because the maps are on the host. Multiple keyboards with D01 engraved with different symbols will not actually vary anything, and all send the same thing across the wire.
Maybe not for 450 keys (!), but I would dearly love to be able to type all the diacritical marks and at least select Unicode ranges (Cyrillic and Greek).
It's been a really low-priority desire (I won't dignify it with "need") and so I haven't even really worked out a layout or even carefully defined what I'd like, but yeah, the Really Big Keyboard would fill at least a small need.
In A.I. War (book by Daniel Keys Moran), Trent uses a "custom 240-point Unicode board" to code in SuperLISP, which originally put the idea in my head. I asked Moran about this. He made it up whole cloth. No such keyboard exists. Of course, we still have ample time to invent one before the time of that story.
If you persuade your operating system to load up keyboard maps with the ISO 9995 common secondary group, you will get all of the combining diacritical marks at least. They're mostly on level 3 of group 2.
Splitting a keyboard has ergonomic benefits. I don't see that "full keyboard for each hand" would be an advantage. One of the more popular split keyboards is the Corne Keyboard.
https://github.com/foostan/crkbd
https://web.archive.org/web/20200916174120/https://relivesig...
The image itself: https://web.archive.org/web/20200916210058/https://doc-14-a0...