2025-08-16

keyboards

a brief overview

keycaps

form factor of the user-facing surface.

  • surface profile: flat, cylindrical, spherical
  • row shaping: flat, sculpted by row, tower-staggered
  • height: ultralow, low, standard, tall

  • family:

    • low-profile: reduced height, usually cylindrical or flat; optimized for thin keyboards
    • oem: medium height, cylindrical, sculpted by row; default for many mass-market boards
    • cherry: medium-low height, cylindrical, sculpted; compact vertical profile, widely used
    • sa: very tall, spherical, tower-staggered; retro aesthetic, heavy key travel feel
    • dsa: uniform height, spherical, flat rows; easily rearrangeable, consistent profile
    • xda: low height, wide tops, spherical, flat rows; uniform but with more surface area than dsa
  • shaft depth: raised, flush

  • material: abs single/double, pbt dye-sub/double, pom

    • pbt double-shot: durable, clear legends

  • unit sizes (ansi):

    • 1u: letters, numbers, punctuation, ctrl, alt
    • 1.25u: bottom-row modifiers
    • 1.5u: tab, caps lock
    • 2u: numpad 0, numpad +, numpad enter
    • 2.25u: left shift
    • 2.75u: right shift
    • 6.25u: spacebar
    • others: 1.75u caps lock or right shift (compact variants)

  • mount systems

    • stems (main interface):

      • cherry mx cross: dominant, widest compatibility
      • alps: legacy rectangular stem
      • topre: slider-over-dome, proprietary
      • scissor: dual-hinge, flat
      • optical/hall custom: varied, vendor-specific
      • pos mount: rectangular industrial form

    • stabilizers (large-key support):

      • none: standard for 1u keys

      • dual-stem: two functional stems (common in 2u keys, e.g. numpad 0)

      • single stem + support posts: one functional stem, plastic supports left/right

      • wire stabilizers: bar connecting to clips or inserts; used on spacebar, shift, enter

switches

mechanism converting press to signal.

types

  • scissor: quietest, ultralow profile, short actuation depth, tolerant to angled presses; dominant in laptops and compact boards
  • hall-effect: non-contact, analog depth sensing, highly durable, allows configurable actuation points
  • cherry mx: canonical family, linear/tactile/clicky variants with wide ecosystem
  • ultralow mx, standard mx, optical, membrane, capacitive

mounting

  • hot-swap: tool-less replacement
  • soldered

spring

  • coil, leaf, torsion, none

characteristics

  • actuation type: linear, tactile (bump), clicky (bump + sound)
  • actuation force: light (<45 g), medium (45-60 g), heavy (>60 g)
  • actuation distance: 1-2 mm typical
  • total travel: 2-4 mm typical
  • durability: 50-100+ million presses
  • acoustic profile: silent, quiet-damped, tactile, clicky

layouts

arrangement and form of keys.

standards

  • ansi, iso, jis, custom

    • ansi: symmetric shifts, easier keycap sourcing, compact enter

sizes

  • 100%: function keys, arrows, numpad
  • tkl (80%): function keys, arrows, no numpad
  • 75%: arrows and function keys, denser
  • 65%: arrows, no function keys, compact
  • 60%: no arrows, no function keys, minimal
  • <40%: reduced layers, often programmable

purposes of extra keys

  • arrows: text navigation, word skipping with modifiers
  • function keys: shortcuts, system control, programming contexts
  • numpad: efficient one-hand number entry, common in games and finance

ergonomics

typing comfort.

  • sculpted layouts: concave wells or height tiers
  • split keyboards: halves separated, may reduce shoulder strain if matching shoulder distance
  • arm rests: offset case height, prevent wrist extension
  • compact/numpad-less: reduce lateral reach distance to mouse.
  • flat-profile keys: allow angled presses, not as strictly vertical

connectivity

interface and power.

  • cable: usb-c, usb-a
  • wireless: bluetooth, 2.4 ghz dongle. occasional re-pairing, pairing delays, and even transmission delays or signal obstruction are possible
  • power: external (wired), internal rechargeable battery (battery will eventually fail or lose charge, regular charging necessary which may lead to critical need with insufficient charge)

input performance

responsiveness and key detection.

  • polling rate: 125 hz (8 ms), 250 hz (4 ms), 500 hz (2 ms), 1000 hz (1 ms), 2000 hz+ (sub-ms)

    • high polling (>1000 hz): gaming, esports latency reduction
    • standard (125-500 hz): sufficient for typing and general use

  • key rollover: 2KRO, 6KRO, NKRO

    • 6KRO: common USB limit

    • NKRO: full simultaneous key detection, preferred in gaming/enthusiast boards

noise

sources of sound during typing.

causes

  • bottom-out: stem hitting switch base
  • top-out: stem slamming into housing when released
  • wobble: lateral play of keycaps and stems
  • case transmission: vibrations carried by keyboard chassis
  • desk resonance: low-frequency amplification from surface coupling
  • case weight: heavier cases reduce high-frequency sharpness, but do not prevent low-frequency desk resonance

mitigation

  • small-radius corner pads: most effective; isolate contact points, filter low frequencies, eliminate deep desk resonance, leave only intrinsic switch sounds
  • switch lubing: reduces friction and spring noise
  • case padding: foam inserts absorb vibration inside chassis
  • broad foam mats: still low-frequency coupled to the desk

use cases

optimum hardware depends on what the keyboard primarily triggers.

text entry

  • trigger type: discrete characters
  • requirements: high rollover (>= 6KRO), low-profile or scissor switches, short actuation depth, consistent feel
  • polling: >= 125 hz (500 hz optional, no benefit beyond)
  • noise control: important in office/shared environments

gaming - digital

  • trigger type: discrete game functions
  • requirements: low latency, high rollover (NKRO), durable linear or tactile switches, consistent reset
  • polling: >= 1000 hz (higher rates unnecessary for digital keys)
  • noise: less critical than latency

gaming - analog

  • trigger type: one-dimensional continuous (key depth mapped as analog axis)
  • requirements: hall-effect or optical analog switches, adjustable actuation points, smooth travel
  • polling: >= 1000 hz minimum; 2000–8000 hz improves depth granularity
  • noise: secondary consideration

special/industrial

  • trigger type: macros, control codes, machine functions
  • requirements: reliable switches (hall, capacitive), programmable layouts, rugged cases
  • polling: >= 125 hz (standard sufficient)
  • noise: often irrelevant

typing systems

input methods and layouts beyond physical design.

techniques

  • 10-finger system: maximizes efficiency, reduces hand travel
  • number row typing: allows 10-finger entry of digits, space-efficient alternative to numpad

logical layouts

  • qgmlwb and others: niche, maximize efficiency at cost of compatibility
  • colemak: keeps many qwerty shortcuts; balances load across hands; smoother transition path
  • dvorak: places common English letters on home row, but biased toward right hand; efficiency vs qwerty, less compatible
  • qwerty: legacy, widespread, highest compatibility see also carpalx.

brands

wooting (hall analog), lowfree, nuphy, keychron, mistel, varmilo, typematrix (matrix layout), kinesis (ergonomic split), cherry

references

  • cherry kc4000: compact scissor, discontinued