============================================ mechanical aspects of Kinesis Advantage keys ============================================ by Andrew Main (Zefram) 2012-04-17 abstract -------- The keycaps on a Kinesis Advantage keyboard are measured in their simple mechanical features, with a view to being able to source compatible customised keycap sets. table of contents ----------------- 0. context 1. top row 2. regular keys 3. observations 4. references 0. context ========== The Kinesis Advantage [KINESIS] is a keyboard of relatively radical ergonomic design. Its most notable feature is that most of the keys are arranged into three-dimensional bowls, one for each hand, intended to match the natural travel of the fingers. Whereas conventional keyboards have a mostly flat profile, and achieve a small degree of ergonomic arrangement by using a different keycap profile in each row, the Advantage achieves its profile by a combination of three-dimensional switch mounting and some keycap shape variation. The keycap shapes are not specific to the Advantage. They are all conventional shapes designed for flat keyboards, but their layout (and therefore labelling) is peculiar to the Advantage. A keycap set intended for a flat keyboard will not fit the Advantage. The Advantage has a total of 86 keys, arranged in six groups in a bilaterally symmetric manner. On each side there is a group of 6 keys for the thumb, 28 for the other fingers, and a row of 9 that are out of normal reach. Ignoring the third dimension of the main key groups, and the slight rotation of the thumb keys, the key layout can be diagrammatically represented thus: +--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+ |es|F1|F2|F3|F4|F5|F6|F7|F8| |F9|Ft|Fe|Fz|ps|sl|pb|kp|pg| +--+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+--+ +----+---+---+---+---+---+ +---+---+---+---+---+----+ |=+ |1! |2@ |3# |4$ |5% | |6^ |7& |8* |9( |0) |-_ | +----+---+---+---+---+---+ +---+---+---+---+---+----+ |tb |qQ |wW |eE |rR |tT | |yY |uU |iI |oO |pP |\| | +----+---+---+---+---+---+ +---+---+---+---+---+----+ |cl |aA |sS |dD |fF |gG | |hH |jJ |kK |lL |;: |'" | +----+---+---+---+---+---+ +---+---+---+---+---+----+ |ls |zZ |xX |cC |vV |bB | |nN |mM |,< |.> |/? |rs | +----+---+---+---+---+---+ +---+---+---+---+---+----+ |`~ |<> |lf |rg | |up |dn |[{ |]} | +---+---+---+---+ +---+---+---+---+ +---+---+ +---+---+ |lc |la | |ra |rc | +---+---+---+ +---+---+---+ |bs |dl |hm | |pu |rt |sp | | | +---+ +---+ | | | | |en | |pd | | | +---+---+---+ +---+---+---+ For identification purposes, this diagram labels each key with its meaning in the conventional US QWERTY layout. Ordinary character keys are represented by the two characters they produce (unshifted and shifted), and other keys are labelled according to their function. The non-obvious labels are: <> extra char hm Home pu Page Up Fe F11 kp [Keypad] ra right Alt Ft F10 la left Alt rc right Ctrl Fz F12 lc left Ctrl rg Right bs Backspace lf Left rs right Shift cl Caps Lock ls left Shift rt Return dl Delete pb Pause/Break sl Scroll Lock dn Down pd Page Down sp Space en End pg [Progrm] tb Tab es Escape ps PrtSc/SysRq up Up These key meanings are not in themselves significant to this work. With the exception of the "Keypad" and "Progrm" keys, which have fixed meanings local to the keyboard, the keys can all be remapped both in keyboard firmware and in OS software. These key labels are used only to refer to the physical keys and their locations. This work refers to an Advantage purchased in 2012. Older Advantage keyboards are known to have a different set of keycaps. 1. top row ========== The eighteen keys of the top row are not proper typing keys. They are small rubber buttons, with a low-quality switch mechanism. They each measure 7.6 mm +- 0.1 mm lateral-medial and 10.5 mm +- 0.1 mm front-back. These keys are not amenable to replacement of keycaps. Those seeking to customise the keys of an Advantage will inevitably leave this row untouched. Those customising the key layout should arrange for these keys to stay untouched in a more literal sense. 2. regular keys =============== The remaining 68 keys have conventional replaceable keycaps. They each have a Cherry MX brown-stem switch, so the keycaps all have Cherry MX mountings. In each case the mounting is recessed (relative to the skirt of the keycap) by 1.0 mm +- 0.3 mm. The legends are surface printed onto the keycaps. The keycaps fall into ten distinct species, which will now be described separately. For each, the information given is: (a) Orthogonal dimensions of the rectangular base, +- 0.1 mm. (b) Orthogonal dimensions of the key top, +- 0.3 mm. This is measured from directly from side to side in three-dimensional space, not following the curvature of the top. (c) General shape and orientation of the top surface's indentation. (d) Angles of slope of the four sides, +- 5 deg. These are stated relative to the horizontal plane (defined by the skirt of the keycap), so a measurement of 90 deg represents a vertical side. (e) Angle and direction of the top surface's dominant slope, +- 1 deg. (f) Height from skirt to corners, +- 0.1 mm. (g) Thickness of skirt, +- 0.1 mm. (h) Markings found on the underside of the keycap. (i) Count and list of keys of this species. The keycap species are: #0 base size: 18.1 mm lateral-medial and 18.1 mm front-back top size: 12.4 mm lateral-medial and 14.6 mm front-back top shape: cylindrical on front-back axis face slopes: lateral and medial 75 deg, front 80 deg, back 85 deg top slope: 5.0 deg to front height: 14.6 mm at back, 13.7 mm at front skirt thickness: 1.0 mm underside markings: number cardinality: 4 instances on left: lc la instances on right: rc ra #1 base size: 18.1 mm lateral-medial and 18.0 mm front-back top size: 12.5 mm lateral-medial and 14.4 mm front-back top shape: cylindrical on front-back axis face slopes: lateral and medial 75 deg, front 70 deg, back 85 deg top slope: 2.0 deg to front height: 11.5 mm at back, 11.1 mm at front skirt thickness: 0.8 mm underside markings: number cardinality: 10 instances on left: 1! 2@ 4$ 5% hm instances on right: 0) 9( 7& 6^ pu #2 base size: 18.0 mm lateral-medial and 18.0 mm front-back top size: 12.6 mm lateral-medial and 14.8 mm front-back top shape: cylindrical on front-back axis face slopes: lateral and medial 75 deg, front 70 deg, back 85 deg top slope: 1.0 deg to back height: 9.4 mm at front, 9.1 mm at back skirt thickness: 0.9 mm underside markings: "R3" and number cardinality: 12 instances on left: 3# qQ wW eE rR tT instances on right: 8* pP oO iI uU yY #3 base size: 18.1 mm lateral-medial and 18.0 mm front-back top size: 12.8 mm lateral-medial and 14.5 mm front-back top shape: cylindrical on front-back axis face slopes: lateral and medial 75 deg, front 70 deg, back 85 deg top slope: 7.0 deg to back height: 9.3 mm at front, 8.0 mm at back skirt thickness: 0.9 mm underside markings: "R2" and number cardinality: 4 instances on left: gG en instances on right: hH pd #4 base size: 18.1 mm lateral-medial and 18.0 mm front-back top size: 13.0 mm lateral-medial and 14.4 mm front-back top shape: cylindrical on front-back axis face slopes: lateral and medial 75 deg, front 70 deg, back 85 deg top slope: 15.5 deg to back height: 10.2 mm at front, 8.0 mm at back skirt thickness: 0.9 mm underside markings: "R1" and number cardinality: 18 instances on left: zZ xX cC vV bB `~ <> lf rg instances on right: /? .> ,< mM nN ]} [{ dn up #5 base size: 18.0 mm lateral-medial and 18.0 mm front-back top size: 12.3 mm lateral-medial and 12.3 mm front-back top shape: pyramidal face slopes: all 90 deg on lower part and 55 deg on upper part top slope: none height: 9.6 mm all round skirt thickness: 0.8 mm underside markings: none cardinality: 8 instances on left: aA sS dD fF instances on right: ;: lL kK jJ #6 base size: 22.8 mm lateral-medial and 18.0 mm front-back top size: 17.5 mm lateral-medial and 14.5 mm front-back top shape: cylindrical on front-back axis face slopes: lateral and medial 75 deg, front 70 deg, back 85 deg top slope: 2.0 deg to front height: 11.5 mm at back, 11.0 mm at front skirt thickness: 0.8 mm underside markings: none cardinality: 2 instances on left: =+ instances on right: -_ #7 base size: 22.9 mm lateral-medial and 18.0 mm front-back top size: 17.6 mm lateral-medial and 14.6 mm front-back top shape: cylindrical on front-back axis face slopes: lateral and medial 75 deg, front 70 deg, back 85 deg top slope: 6.5 deg to back height: 9.4 mm at front, 8.1 mm at back skirt thickness: 0.8 mm underside markings: number cardinality: 6 instances on left: ls cl tb instances on right: rs '" \| #8 base size: 18.0 mm lateral-medial and 37.1 mm front-back top size: 12.4 mm lateral-medial and 33.4 mm front-back top shape: cylindrical on front-back axis face slopes: lateral and medial 75 deg, front 70 deg, back 85 deg top slope: 4.0 deg to back height: 10.3 mm at front, 7.9 mm at back skirt thickness: 0.9 mm underside markings: "E" cardinality: 2 instances on left: bs instances on right: sp #9 base size: 18.0 mm lateral-medial and 37.1 mm front-back top size: 14.5 mm lateral-medial and 31.8 mm front-back top shape: cylindrical on lateral-medial axis face slopes: front and back 75 deg, lateral 70 deg, medial 85 deg top slope: 16.0 deg to medial height: 10.4 mm at lateral, 8.0 mm at medial skirt thickness: 0.9 mm underside markings: "R1", "2.0", and number cardinality: 2 instances on left: dl instances on right: rt Diagrammatically, the arrangement of the keycap species is: 6 1 1 2 1 1 1 1 2 1 1 6 7 2 2 2 2 2 2 2 2 2 2 7 7 5 5 5 5 3 3 5 5 5 5 7 7 4 4 4 4 4 4 4 4 4 4 7 4 4 4 4 4 4 4 4 0 0 0 0 8 9 1 1 9 8 3 3 3. observations =============== Many of the dimensions, independently measured for each species, match sufficiently closely that they presumably arise from identical design dimensions. In horizontal cross-section, the keycaps can all be trivially identified as standard sizes based on the standard key pitch of 0.75 in (19.05 mm). Species #0 to #5 are 1x1 keys, #6 and #7 are 1.25x1, and #8 and #9 are 1x2. Most are being used in their nominal orientation, but the 1x2 #9 is clearly actually a 2x1 key that has been rotated. Species #5 is of a very different style from the others, which all stylistically match each other. #5 is used for the non-thumb home keys, and its different top shape gives an obvious tactile clue in homing. If these keys did not have such a radically different shape, they would presumably be of species #3, used for the non-home key on the same row. However, their height and slope are actually better approximated by species #2. The top slopes allow the key shapes (other than species #5) to be associated, with high confidence, with the rows of flat keyboards for which they were designed. Species #0 is for the third row behind home; #1 and #6 are for the second row behind home; #2 is for the first row behind home; #3 and #7 are for the home row; #4 and #9 are for the first row in front of home; and #8 is to span two rows including at least one in front of home. 4. references ============= [KINESIS] Kinesis Corp., "Contoured Keyboard Model Features" (advertisement), .