Software is as critical as hardware: The UHK supports holding a key down to select a different keymap layer, then using the other hand to tap a key in that layer. While few people learn many-key chording, "one finger each hand" is every bit as easy as ordinary typing, with practice. This supports an n^2 expansion in effective keyboard reach. I'm surprised this isn't the norm for selecting Chinese/Japanese characters.
The question is: How well? I'm not entirely happy with my QMK firmware implementation. Tap-hold is the antithesis of n-key rollover; one needs to learn to properly nest key-down, key-up events. It's easy to switch from a clarinet (cleanly cover holes) to a saxophone (slap pads), but hard switching back. And we've all learned to type like we're on a saxophone, relying on n-key rollover to cover many sins.
I now use QMK firmware with Hasu controllers for multiple Leopold FC660C keyboards with Topre Silent 45g "rubber dome" key switches. After trying dozens of mechanical key switches, I found that nothing feels like a Topre switch.
And here's the kicker: The physical form factor doesn't matter so much if your fingers rarely go far from home row, which is what tap/hold facilitates.
You can modify the uhk firmware quite extensively with the included Agent application. I typically stick to holding a keys to access different layers, but you can also double tap them to make it stick to a new layer. I only rarely use that functionality myself tho.
Being able to modify each button, in each layer has it's downsides tho: if I'm ever on a keyboard other than my own, I can barely type anymore!
I've edited away my most common typos on my keyboard layout, eg the key that's normally caps lock is just another shift key in my keyboard, since I find only ever use that key by mistake.
Now when I'm on another keyboard I hit it all the time, since I'm so used to it not being a problem
Software is as critical as hardware: The UHK supports holding a key down to select a different keymap layer, then using the other hand to tap a key in that layer. While few people learn many-key chording, "one finger each hand" is every bit as easy as ordinary typing, with practice. This supports an n^2 expansion in effective keyboard reach. I'm surprised this isn't the norm for selecting Chinese/Japanese characters.
The question is: How well? I'm not entirely happy with my QMK firmware implementation. Tap-hold is the antithesis of n-key rollover; one needs to learn to properly nest key-down, key-up events. It's easy to switch from a clarinet (cleanly cover holes) to a saxophone (slap pads), but hard switching back. And we've all learned to type like we're on a saxophone, relying on n-key rollover to cover many sins.
I now use QMK firmware with Hasu controllers for multiple Leopold FC660C keyboards with Topre Silent 45g "rubber dome" key switches. After trying dozens of mechanical key switches, I found that nothing feels like a Topre switch.
And here's the kicker: The physical form factor doesn't matter so much if your fingers rarely go far from home row, which is what tap/hold facilitates.