| 1 | # KEBA - A Keyboard # |
| 2 | |
| 3 | The goal is a keyboard suitable both as a general purpose UNIX workstation |
| 4 | keyboard and as a NED keyboard. The project name is KEBA. |
| 5 | |
| 6 | ## Size ## |
| 7 | |
| 8 | Picture a rectangle from the bottom-left `Control` key to the upper right |
| 9 | `Backspace` on a traditional 104-key keyboard. That entire block is the *core*. |
| 10 | |
| 11 | When my hands leave the core, it is as disruptive to my typing as when I reach |
| 12 | for the mouse. Thus, the new keyboard will only be the size of the core. In |
| 13 | order to utilize the large number of pre-existing keyboard cases and |
| 14 | accessories, I will target the "60% keyboard" size, mounting holes and connector |
| 15 | location. |
| 16 | |
| 17 | ## Layout ## |
| 18 | |
| 19 | The single, universal piece of advice I have received is that, if I want to |
| 20 | retain my muscle memory for a traditional keyboard, my alterations must not be |
| 21 | minor. Only a significant break from a traditional layout will allow my brain |
| 22 | to train a new set of memories without meddling with the old set. |
| 23 | |
| 24 | I'm going to follow that advice. |
| 25 | |
| 26 | ### Physical Layout ### |
| 27 | |
| 28 | Many of the keys accessible on a traditional keyboard via extending my pinky |
| 29 | finger (think: `-=[]\'/.`) are difficult to hit accurately. I consistently end |
| 30 | up one key off when trying to enter any kind of brace (`(){}[]`). However, my |
| 31 | pinky was able to easily navigate the block of function keys adjoined to the |
| 32 | left side of the keyboard core on a Sun keyboard. |
| 33 | |
| 34 | As those Sun keys are laid out in a grid, a pure ortholinear layout seems |
| 35 | logical. This also plays into the 'sufficiently different' criteria. By |
| 36 | forcing my fingers to move to unaligned (w.r.t. a traditional keyboard) |
| 37 | locations, my brain should switch back to traditional layout when presented |
| 38 | with a staggered keyboard. |
| 39 | |
| 40 | Since the block Sun adjoined was a 2x5 grid and the upper-most and lower-most |
| 41 | keys were at the edge of comfort, we will go with five rows. This fits cleanly |
| 42 | into the 60% keyboard case. |
| 43 | |
| 44 | Although a 60% case will allow 15 columns of keys, it was difficult to |
| 45 | accurately place my hand on top of the outermost function keys, instead |
| 46 | frequently sliding over the key while pressing it down. To avoid this, remove |
| 47 | one column of keys and make the two outermost columns 1.5u wide. |
| 48 | |
| 49 | After analyzing my keystrokes by lightly marking the top of my keys, I |
| 50 | discovered that my spacebar is only struck over a surface corresponding to 2.5 |
| 51 | key widths. Given the ortholinear layout, we will reduce the spacebar to 2u |
| 52 | wide and include multiple 2u buttons. |
| 53 | |
| 54 | Putting together the current criteria, we arrive at the following layout: |
| 55 | |
| 56 | ![](/projects/ned/keyboard_images/001_kb_img.png "") |
| 57 | |
| 58 | ### Logical Layout ### |
| 59 | |
| 60 | We first consider the alphanumerics. This consists of a 10x4 grid with four |
| 61 | empty spots (the `;/.,` keys). When placing it into the 12x4 space available, |
| 62 | split it to allow for a wider spread of the hands, creating an easier angle on |
| 63 | the wrists. This also avoids a double column of utility keys on the outer ends |
| 64 | of the board, instead moving one column from each side into the middle and |
| 65 | making it easier to accurately hit the pinky-associated utility keys. |
| 66 | |
| 67 | The alphabetic keys will reside in a modified Colemak configuration with the |
| 68 | `U` key moving down two spots, just to the right of the `M` key, and the `O` |
| 69 | key moving to the `U` key's old location. This modified Colemak layout allows |
| 70 | placement of `Escape` directly underneath the right pinky. |
| 71 | |
| 72 | While we're at it, rearrange the numbers into the correct order. |
| 73 | |
| 74 | That thinking generates this alphanumeric+`Escape` core layout: |
| 75 | |
| 76 | ![](/projects/ned/keyboard_images/002_kb_img.png "") |
| 77 | |
| 78 | The remaining special keys are |
| 79 | |
| 80 | Tab, Shift, Control, Alt, Space, Enter, Backspace. |
| 81 | |
| 82 | Since `Backspace` is never pressed in the course of regular typing, we locate |
| 83 | it at middle-top where each index finger can reach it with a small stretch. |
| 84 | Given their frequent use, `Space` and `Enter` are placed under the thumbs. |
| 85 | `Shift` moves to the most convenient pinky location. Then `Tab` is placed |
| 86 | underneath that location, still easily accessible but the least accessible of |
| 87 | the `Ctrl`/`Shift`/`Tab` combo. |
| 88 | |
| 89 | My computing environment uses `Alt` to send instructions to the operating |
| 90 | environment and `Control` to send instructions to individual programs. |
| 91 | Consequently, we place `Control` to the left of the `QWFPG` row for convenient |
| 92 | use with the left side alphabetic keys and place `Alt` bottom-center so the |
| 93 | entire keyboard is easily reached while it is depressed. |
| 94 | |
| 95 | In practice, I found that I never use the right hand `Alt`, `Shift` or |
| 96 | `Control` so there will be only one of each on this keyboard. |
| 97 | |
| 98 | Arrow keys are assigned under the assumption that up/down arrow keys should not |
| 99 | share a hand with `Enter` since one frequently pages through a list with |
| 100 | up/down arrows and selects with `Enter`, like when selecting a command from the |
| 101 | command line history. By keeping them on separate sides of the board, both |
| 102 | hands can be used. |
| 103 | |
| 104 | The four corner keys will be reserved for user-programmable shortcuts. |
| 105 | |
| 106 | That leaves us with the following layout: |
| 107 | |
| 108 | ![](/projects/ned/keyboard_images/003_kb_img.png "") |
| 109 | |
| 110 | Finally, all the remaining keys will be mapped via four overlays, selectable |
| 111 | via two Meta keys on the bottom row. Holding a combination of these keys down |
| 112 | will select the overlay. A single tap of the key will enable the overlay for a |
| 113 | single additional keypress. A double-tap of the key will lock the overlay on, |
| 114 | or turn it off. |
| 115 | |
| 116 | Via this mechanism, the remaining 12 blank keys can encode 48 values. |
| 117 | |
| 118 | Importantly, overlays will NOT change any keys other than these 12 blank keys. |
| 119 | Every key in the following set will remain unchanged in every overlay: |
| 120 | |
| 121 | a-z, 0-9, Control, Shift, Alt, Tab, Space, |
| 122 | Enter, Backspace, Arrows, Escape, Meta1, Meta2 |
| 123 | |
| 124 | At a minimum, the overlays need to include the following characters from a |
| 125 | standard 104-key: |
| 126 | |
| 127 | `~!@#$%^&*()_+-=[]{}\|;:'",.?/<> |
| 128 | |
| 129 | Including other characters, say some logic and set theory symbols, is enticing |
| 130 | but would require a custom keyboard definition in each OS I use. Perhaps |
| 131 | careful assignment of keycodes so as to stay outside the standard 104-key |
| 132 | definitions would allow a 'compatibility' mode. For that reason, I would like |
| 133 | to keep the combined (`Meta1`+`Meta2`) overlay blank, if possible. |
| 134 | |
| 135 | Assignment of the overlay keys is still tentative. |
| 136 | |
| 137 | I know I want all the brackets down the middle. The remaining assignments are |
| 138 | made in consideration of the key's frequency of use in/at normal English |
| 139 | writing, the UNIX command line, and the C programming environment. Allowing |
| 140 | overlap, I see those sets as follows. |
| 141 | |
| 142 | English Language: |
| 143 | |
| 144 | !,.? |
| 145 | |
| 146 | UNIX Commandline: |
| 147 | |
| 148 | `~&*_-\/|" |
| 149 | |
| 150 | C Language: |
| 151 | |
| 152 | #&*-+=;:'",/ |
| 153 | |
| 154 | Other: |
| 155 | |
| 156 | @$%^ |
| 157 | |
| 158 | When assigning overlays, since the 'extra' overlay buttons are on the right |
| 159 | hand side, the left overlay button, or `Meta1`, should take precedence over the |
| 160 | right overlay button. In other words, the priority should be: |
| 161 | |
| 162 | Default > Meta1 > Meta2 > Meta1+Meta2 |
| 163 | |
| 164 | The following are the three overlays as currently assigned: |
| 165 | |
| 166 | ![](/projects/ned/keyboard_images/004_kb_img.png "") |
| 167 | |
| 168 | ![](/projects/ned/keyboard_images/005_kb_img.png "") |
| 169 | |
| 170 | ![](/projects/ned/keyboard_images/006_kb_img.png "") |
| 171 | |
| 172 | ## Keyswitches ## |
| 173 | |
| 174 | In the linear vs clicky vs tactile decision, my *normal* is most people's |
| 175 | *extreme*. I consider an IBM Model M to be the baseline for an adequate |
| 176 | computer keyboard, not some ultimate endpoint. |
| 177 | |
| 178 | The switches most frequently recommended for someone that likes the Model M are |
| 179 | the Cherry MX Greens. I already use MX Blues from the same family to repair |
| 180 | Tektronix terminals and find the tactile style suitable. If the information on |
| 181 | the internet is to be believed, MX Greens are still lighter than a Model M but |
| 182 | are the heaviest MX-series switches on the market. |
| 183 | |
| 184 | It might make sense to install Mill-Max sockets in one PCB so I can easily swap |
| 185 | keyswitches until I find what I want, despite the cost. Even if the MX Greens |
| 186 | are where I settle, I won't know they're *right* until I also try some other |
| 187 | switches. |
| 188 | |
| 189 | ## Keycaps ## |
| 190 | |
| 191 | Keycaps should be either the full SA profile, or all SA Row 3 profile. |
| 192 | Alphanumeric caps should have a SINGLE character on them, not a double printing |
| 193 | that includes the 'shifted' character. All overlay and most non-alphanumeric |
| 194 | caps like Space and Enter should be blank. Meta keys can be playful, consider |
| 195 | PLOT/STOP or BREAK/RESET from my existing keycap inventory. |
| 196 | |
| 197 | ## Computer Interface ## |
| 198 | |
| 199 | Since both QMK and the STM32 natively support USB, that is a natural interface |
| 200 | to choose. |
| 201 | |
| 202 | Alternatively, I could expose a logic level UART and design a series of inline |
| 203 | dongles to convert to whatever signalling I want. That allows me to easily |
| 204 | connect the keyboard in place of a USB, PS/2, Sun Type 3 & 5, Tektronix |
| 205 | terminal, etc keyboard. This option would require custom firmware. |
| 206 | |
| 207 | ## Human Interface ## |
| 208 | |
| 209 | The keyboard should include LED lights behind the keys for use in communicating |
| 210 | with the user. By default, the lights should be off and should only briefly |
| 211 | light to communicate. At a minimum, there should be a different blink for each |
| 212 | Meta key to indicate when it is triggered/toggled. Perhaps multi-color LEDs to |
| 213 | indicate the different overlays? |
| 214 | |
| 215 | If using USB, expose a virtual UART to the host that allows for configuration. |
| 216 | If using a generic UART, configure the keyboard to enter a programming mode on |
| 217 | that same UART when some contrived combination of keys is pressed. Either way, |
| 218 | the keyboard should be easily configurable via a human-readable UART interface. |
| 219 | |
| 220 | ## Firmware ## |
| 221 | |
| 222 | If I use a USB interface, I can copy my STM32 circuit from Liquid Fusion and |
| 223 | use it with QMK until I get around to writing my own code. Will QMK support the |
| 224 | 'toggle by double-tap' feature I envison for the Meta keys? |
| 225 | |
| 226 | ## Template ## |
| 227 | |
| 228 | The following JSON is a template of the static key assignments that can be |
| 229 | uploaded to <http://www.keyboard-layout-editor.com/>. |
| 230 | |
| 231 | [ |
| 232 | [ |
| 233 | { |
| 234 | "c": "#ffffff", |
| 235 | "t": "000000", |
| 236 | "p": "SA R3", |
| 237 | "sm": "cherry", |
| 238 | "sb": "cherry", |
| 239 | "st": "MX1A-F1xx", |
| 240 | "a": 7, |
| 241 | "f": 9, |
| 242 | "w": 1.5 |
| 243 | }, |
| 244 | "", |
| 245 | "Ø", |
| 246 | "1", |
| 247 | "2", |
| 248 | "3", |
| 249 | "4", |
| 250 | { |
| 251 | "f": 4, |
| 252 | "w": 2 |
| 253 | }, |
| 254 | "ERASE", |
| 255 | { |
| 256 | "f": 9 |
| 257 | }, |
| 258 | "5", |
| 259 | "6", |
| 260 | "7", |
| 261 | "8", |
| 262 | "9", |
| 263 | { |
| 264 | "w": 1.5 |
| 265 | }, |
| 266 | "" |
| 267 | ], |
| 268 | [ |
| 269 | { |
| 270 | "f": 4, |
| 271 | "w": 1.5 |
| 272 | }, |
| 273 | "CONTROL", |
| 274 | { |
| 275 | "f": 9 |
| 276 | }, |
| 277 | "Q", |
| 278 | "W", |
| 279 | "F", |
| 280 | "P", |
| 281 | "G", |
| 282 | "", |
| 283 | "", |
| 284 | "J", |
| 285 | "L", |
| 286 | "O", |
| 287 | "Y", |
| 288 | "", |
| 289 | { |
| 290 | "w": 1.5 |
| 291 | }, |
| 292 | "" |
| 293 | ], |
| 294 | [ |
| 295 | { |
| 296 | "f": 4, |
| 297 | "w": 1.5 |
| 298 | }, |
| 299 | "SHIFT", |
| 300 | { |
| 301 | "f": 9 |
| 302 | }, |
| 303 | "A", |
| 304 | "R", |
| 305 | "S", |
| 306 | "T", |
| 307 | "D", |
| 308 | "", |
| 309 | "", |
| 310 | "H", |
| 311 | "N", |
| 312 | "E", |
| 313 | "I", |
| 314 | { |
| 315 | "f": 4 |
| 316 | }, |
| 317 | "ESC", |
| 318 | { |
| 319 | "f": 9, |
| 320 | "w": 1.5 |
| 321 | }, |
| 322 | "" |
| 323 | ], |
| 324 | [ |
| 325 | { |
| 326 | "f": 4, |
| 327 | "w": 1.5 |
| 328 | }, |
| 329 | "TAB", |
| 330 | { |
| 331 | "f": 9 |
| 332 | }, |
| 333 | "Z", |
| 334 | "X", |
| 335 | "C", |
| 336 | "V", |
| 337 | "B", |
| 338 | "", |
| 339 | "", |
| 340 | "K", |
| 341 | "M", |
| 342 | "U", |
| 343 | "", |
| 344 | "", |
| 345 | { |
| 346 | "w": 1.5 |
| 347 | }, |
| 348 | "" |
| 349 | ], |
| 350 | [ |
| 351 | { |
| 352 | "w": 1.5 |
| 353 | }, |
| 354 | "", |
| 355 | "<i class='fa fa-long-arrow-up'></i>", |
| 356 | "<i class='fa fa-long-arrow-down'></i>", |
| 357 | { |
| 358 | "f": 4, |
| 359 | "w": 2 |
| 360 | }, |
| 361 | "SPACE", |
| 362 | "M1", |
| 363 | { |
| 364 | "w": 2 |
| 365 | }, |
| 366 | "ALT", |
| 367 | "M2", |
| 368 | { |
| 369 | "w": 2 |
| 370 | }, |
| 371 | "ENTER", |
| 372 | { |
| 373 | "f": 9 |
| 374 | }, |
| 375 | "<i class='fa fa-long-arrow-left'></i>", |
| 376 | "<i class='fa fa-long-arrow-right'></i>", |
| 377 | { |
| 378 | "w": 1.5 |
| 379 | }, |
| 380 | "" |
| 381 | ] |
| 382 | ] |
| 383 | |
| 384 | The following JSON is a template of the overlay keys that can be uploaded to |
| 385 | <http://www.keyboard-layout-editor.com/>. |
| 386 | |
| 387 | [ |
| 388 | [ |
| 389 | { |
| 390 | "c": "#ffffff", |
| 391 | "t": "000000", |
| 392 | "p": "SA R3", |
| 393 | "sm": "cherry", |
| 394 | "sb": "cherry", |
| 395 | "st": "MX1A-F1xx", |
| 396 | "a": 7, |
| 397 | "f": 9, |
| 398 | "w": 1.5, |
| 399 | "d": true |
| 400 | }, |
| 401 | "", |
| 402 | { |
| 403 | "d": true |
| 404 | }, |
| 405 | "", |
| 406 | { |
| 407 | "d": true |
| 408 | }, |
| 409 | "", |
| 410 | { |
| 411 | "d": true |
| 412 | }, |
| 413 | "", |
| 414 | { |
| 415 | "d": true |
| 416 | }, |
| 417 | "", |
| 418 | { |
| 419 | "d": true |
| 420 | }, |
| 421 | "", |
| 422 | { |
| 423 | "f": 4, |
| 424 | "w": 2, |
| 425 | "d": true |
| 426 | }, |
| 427 | "", |
| 428 | { |
| 429 | "f": 9, |
| 430 | "d": true |
| 431 | }, |
| 432 | "", |
| 433 | { |
| 434 | "d": true |
| 435 | }, |
| 436 | "", |
| 437 | { |
| 438 | "d": true |
| 439 | }, |
| 440 | "", |
| 441 | { |
| 442 | "d": true |
| 443 | }, |
| 444 | "", |
| 445 | { |
| 446 | "d": true |
| 447 | }, |
| 448 | "", |
| 449 | { |
| 450 | "w": 1.5, |
| 451 | "d": true |
| 452 | }, |
| 453 | "" |
| 454 | ], |
| 455 | [ |
| 456 | { |
| 457 | "f": 4, |
| 458 | "w": 1.5, |
| 459 | "d": true |
| 460 | }, |
| 461 | "", |
| 462 | { |
| 463 | "f": 9, |
| 464 | "d": true |
| 465 | }, |
| 466 | "", |
| 467 | { |
| 468 | "d": true |
| 469 | }, |
| 470 | "", |
| 471 | { |
| 472 | "d": true |
| 473 | }, |
| 474 | "", |
| 475 | { |
| 476 | "d": true |
| 477 | }, |
| 478 | "", |
| 479 | { |
| 480 | "d": true |
| 481 | }, |
| 482 | "", |
| 483 | "", |
| 484 | "", |
| 485 | { |
| 486 | "d": true |
| 487 | }, |
| 488 | "", |
| 489 | { |
| 490 | "d": true |
| 491 | }, |
| 492 | "", |
| 493 | { |
| 494 | "d": true |
| 495 | }, |
| 496 | "", |
| 497 | { |
| 498 | "d": true |
| 499 | }, |
| 500 | "", |
| 501 | "", |
| 502 | { |
| 503 | "w": 1.5 |
| 504 | }, |
| 505 | "" |
| 506 | ], |
| 507 | [ |
| 508 | { |
| 509 | "f": 4, |
| 510 | "w": 1.5, |
| 511 | "d": true |
| 512 | }, |
| 513 | "", |
| 514 | { |
| 515 | "f": 9, |
| 516 | "d": true |
| 517 | }, |
| 518 | "", |
| 519 | { |
| 520 | "d": true |
| 521 | }, |
| 522 | "", |
| 523 | { |
| 524 | "d": true |
| 525 | }, |
| 526 | "", |
| 527 | { |
| 528 | "d": true |
| 529 | }, |
| 530 | "", |
| 531 | { |
| 532 | "d": true |
| 533 | }, |
| 534 | "", |
| 535 | "", |
| 536 | "", |
| 537 | { |
| 538 | "d": true |
| 539 | }, |
| 540 | "", |
| 541 | { |
| 542 | "d": true |
| 543 | }, |
| 544 | "", |
| 545 | { |
| 546 | "d": true |
| 547 | }, |
| 548 | "", |
| 549 | { |
| 550 | "d": true |
| 551 | }, |
| 552 | "", |
| 553 | { |
| 554 | "f": 4, |
| 555 | "d": true |
| 556 | }, |
| 557 | "", |
| 558 | { |
| 559 | "f": 9, |
| 560 | "w": 1.5 |
| 561 | }, |
| 562 | "" |
| 563 | ], |
| 564 | [ |
| 565 | { |
| 566 | "f": 4, |
| 567 | "w": 1.5, |
| 568 | "d": true |
| 569 | }, |
| 570 | "", |
| 571 | { |
| 572 | "f": 9, |
| 573 | "d": true |
| 574 | }, |
| 575 | "", |
| 576 | { |
| 577 | "d": true |
| 578 | }, |
| 579 | "", |
| 580 | { |
| 581 | "d": true |
| 582 | }, |
| 583 | "", |
| 584 | { |
| 585 | "d": true |
| 586 | }, |
| 587 | "", |
| 588 | { |
| 589 | "d": true |
| 590 | }, |
| 591 | "", |
| 592 | "", |
| 593 | "", |
| 594 | { |
| 595 | "d": true |
| 596 | }, |
| 597 | "", |
| 598 | { |
| 599 | "d": true |
| 600 | }, |
| 601 | "", |
| 602 | { |
| 603 | "d": true |
| 604 | }, |
| 605 | "", |
| 606 | "", |
| 607 | "", |
| 608 | { |
| 609 | "w": 1.5 |
| 610 | }, |
| 611 | "" |
| 612 | ], |
| 613 | [ |
| 614 | { |
| 615 | "w": 1.5, |
| 616 | "d": true |
| 617 | }, |
| 618 | "", |
| 619 | { |
| 620 | "d": true |
| 621 | }, |
| 622 | "", |
| 623 | { |
| 624 | "d": true |
| 625 | }, |
| 626 | "", |
| 627 | { |
| 628 | "f": 4, |
| 629 | "w": 2, |
| 630 | "d": true |
| 631 | }, |
| 632 | "", |
| 633 | "M1", |
| 634 | { |
| 635 | "w": 2, |
| 636 | "d": true |
| 637 | }, |
| 638 | "", |
| 639 | "M2", |
| 640 | { |
| 641 | "w": 2, |
| 642 | "d": true |
| 643 | }, |
| 644 | "", |
| 645 | { |
| 646 | "f": 9, |
| 647 | "d": true |
| 648 | }, |
| 649 | "", |
| 650 | { |
| 651 | "d": true |
| 652 | }, |
| 653 | "", |
| 654 | { |
| 655 | "w": 1.5, |
| 656 | "d": true |
| 657 | }, |
| 658 | "" |
| 659 | ] |
| 660 | ] |
| 661 | |