The layout is the same as that on an accordion.
Come to think of it I remember a friend played the accordion
Anyway, it's still the way to go for electronic keyboards
and the keys can be programmed to sound any note at all.
Many preliminary designs were made before settling on this as the best possible keyboard layout (all things considered). The design immediately preceeding it was a 're-invention' of the Von Janko keyboard first brought into being ~1896. I thought long about why that keyboard failed to catch on and redesigned from the ground up. My keyboard is radically different from anything I have found in historical or current books. (My favorite is the Oxford Companion to Music ... the old one with the sometimes witty and inciteful comments ... not the revised one).
The blue keys on top are a repeat of the white keys. This is necessary to allow easy chord formation, particularly in the left hand (vis. if you can't form a chord one way, the note which is difficult is repeated just above in the blue keys). The keys are not connected as in the Janko keyboard because, remember, this is electronic, not mechanical so there are no considerations other than ergonomics and theoretical chord structure.
One could probably get by with five rows of keys but the sixth row completes the double set and allows automatic transposition to any key since each key has the same fingering. Also, one can run the left hand through the right hand or vise versa which is impossible on a conventional keyboard (simply go over the top of one hand, or under). They don't have to run into each other.
Another advantage of this 3 x 4 key setup is that one can span two octaves in one hand while actually enlarging the keys. Yes ! The keys are wider and can be made very wide depending on how much span you actually want. Personally, I don't think it necessary to span 24 half tones but 16,19 or 21 is quite useful. It allows the other hand to explore the keyboard while the partner does the work of two hands.
Here is a cross section of the keys themselves
Your finger is meant to fit into the trough between the keys facillitating the playing of two keys with one finger (or even three) but mostly to give each key the advantage that the black keys have on a standard keyboard. When you press a black key you are unlikely to accidentally sound the adjacent key because full depression of a black key is roughly even with the white keys undepressed height. So too with every key on this keyboard. The edges should be somewhat rounded to allow one to swipe the keys if desired
. I made a full size paper diagram of this keyboard to test the general feeling of fingering patterns and was very much encouraged by the naturalness of movement with respect to a real piano layout. I believe one could get used to this setup very quickly. The key dimensions that I experimented with were 1" wide x 2.5" tall with a common border with the adjacent key of 1 " and about 7/8" common border with the diagonal adjacent. I think a trough width of 1/2" and top of key width of 1/2" also, might prove to be about right. Experiments on an actual keyboard must be performed to determine what actually works best.
The width of standard keys is ~ 15/16", including the little gap between keys. The length of a standard keyboard is therefore ~ 49". While that of the my board is ~ 31" making it a full foot and a half shorter than standard. Meaning that long jumps and the attending errors are unnecessary. At this size I was just able to span two octaves. So it would also be beneficial to women who can't reach Rachmaninoff size chords.
The Pedal . . .
I have given the pedal design two degrees of freedom.
There should also be an option to mess around with the decay rate of notes which would be equivalent to a variable damper (something which is mechanically possible on a real piano only by a rolling damper which touches the string initially only at the extreme end where its leverage is great enough to maintain the note with something touching the string. I don't know if this has been tried ... it would be difficult ).
By quality of sustain, I mean the sharpness of the sustain along the breath of the board, i.e. something analogous to sostenuto. With this function we determine the default setting for the general sharpness of sustain, then move that sharp point to the left or right by turning the ankle slightly so that the foot is pointing to the left or right side of the keyboard thereby moving the amount of sustain to be given onto the selected notes. If the quantity of sustain is maximized the sharp point disappears at the top of the display, i.e. all notes receive maximum sustain.
I hope I get some feedback on this. I would like to see it made (at least experimentally) and to know if it works as well as I think it will.