Computer Keyboard Design Flaws

By Xah Lee. Date: . Last updated: .

The PC keyboard we use today, sucks big time. Let us count the ways.

generic PC keyboard
A Generic PC Keyboard.

PC keyboard we use is derived from the design of typewriters. The design of the typewriter itself, is largely concerned about getting the machine to actually work. Like most inventions, in the beginning the concern is just to get it to work. The concept of keyboarding ergonomics didn't come about or become popular after some 100 years.

Typewriter Hermes-s
A mechanical typewriter made by Hermes, showing hammer jam. This model is dated in around 1920. 3264×2448

Let's consider some examples.

Let's Use Pinky for Important Keys

The ⌫ Backspace key, the Return ↩ key, are among the most frequently used special keys. However, they are placed in the most inconvenient spots, pressed by the weakest finger the pinky.

Note that originally, on a typewriter of 1800s, these keys are not that frequently used. The Return ↩ exist as a metal bar level for “carriage return”. It is used to move the printing head from end of line position to the beginning of line. It is used once about every 80 chars (per line). The ⌫ Backspace is doesn't exist yet.

But with computers, these keys are two of the most frequently used special keys, more than, say, z or comma.

Let's Make a Beehive

mechanical typewriter keyboard
Keys are staggered so that the levers underneath can be evenly spaced.
` 1 2 3 4 5   6 7 8 9 0 - =
   Q W E R T   Y U I O P [ ] \
    A S D F G   H J K L ; '
     Z X C V B   N M , . /

The vertical key column positions are jagged in irregularity. Look at 1 Q A Z. For the left hand, going from key D to E, your middle finger moves upward and in the direction of your pinky. But for right hand, going from K to I, your middle finger moves up in the direction of your thumb.

Let's Burden Right Pinky

The number of keys for the left/right hands are not symmetric.

` 1 2 3 4 5   6 7 8 9 0 - =
   Q W E R T   Y U I O P [ ] \
   A S D F G   H J K L ; '
   Z X C V B   N M , . /
Standard US layout without slant

In the above diagram, notice how the right side has 6 extra keys, operated by your stretched pinky. Especially bad for programers because we need to type the [ ] { } = + often.

Let's Slow Down Typists

Ever wonder why the letters are arranged that way? Look at the top row of your keyboard, you see: Q W E R T Y. It's arranged that way so that frequent letter combinations are hard to type fast so that the hammers won't jam!

Dvorak keyboard layout
Dvorak keyboard layout

Solution: Dvorak Keyboard Layout.

〔►see Myth of QWERTY vs Dvorak Layout

Let's Space Out Spacebar

keyboard spacy spacebar 2-s
The Space Bar, spanning 5 keys on Apple laptop keyboard.
〔you can buy SPACEBAR sticker at
〔image source

The Space bar, is huge, typically spanning 5 to 6 keys. It's a waste of space! It's that way because it was a lever on mechanical type writers, and the habit stuck.

On older Keyboards up to 1990s, the space bar span 7 to 9 keys! See:

Better design is to have many thumb keys in place of the space bar.

Many modern keyboards now split the space into 2 or more keys. see Tiny Space Bar on Japanese Keyboards and a list at Best Ergonomic Keyboards 2017.

Hand Angle Issues

There are also issues of various hand angles, and hand separation.

Ulnar Deviation

keyboarding RSI ulnar deviation
Ulnar Deviation. 〔image source

Ulnar deviation is solved by split keyboards where the keys are separated into 2 groups.

Forearm Pronation

keyboarding RSI forearm Pronation
Forearm Pronation. 〔image source

Forearm Pronation is solved by split/ergonomic keyboards that are curved/tilted. 〔►see Best Ergonomic Keyboards 2017

Wrist Dorsiflexion

Microsoft sculpt ergonomic keyboard 90852
Microsoft Sculpt Ergonomic Keyboard, solving the wrist dorsiflexion problem by raising the palm rest. Microsoft Ergonomic Keyboard

and there's also wrist dorsiflexion, meaning bending up the palm. This happens when you use a thick keyboard that sits on a flat desk and your forearm rests on the desk surface. Especially bad when the keyboard's back legs are propped up.

This is solved in several ways:

Remedies: Ergonomic Keyboards and Dvorak

Many ergonomic keyboards are popular today, and they fixed most or all these issues. For a list, see: Best Ergonomic Keyboards 2017.

Biomechanics of the Upper Limbs

The standard keyboard creates several biomechanical problems for the operator. First, the hands tend to be ulnarly deviated up to 40° (mean values of 25°; Smutz et al., 1994) placing additional loading on the carpal tunnel and increasing the pressure within the tunnel as much as 13% (Werner et al., 1997). Second, to obtain a flat palm, the forearm tends to be pronated close to the anatomical limit (mean values of 76°), which requires the activation of the forearm muscles (mainly pronator teres and pronator quadratus). Such tension over extended time periods can also lead to muscular fatigue. Third, to compensate for this tension, there is a tendency for operators to lift the upper arms laterally and forward, which requires the activation of the shoulder muscles (primarily the deltoid and teres minor). Again, static tension may lead to fatigue. Fourth, depending on the height and slope of the keyboard, there is a tendency for the wrists to be extended up to 50° (mean values of 23°; Serina et al., 1999). Of all the possible wrist deviations, this wrist extension may be the most critical with carpal tunnel pressures increasing to 63 mmHg (for fingertip forces of 6 N), considerably above 30 mmHg, the threshold level for potential injury (Rempel et al., 1997).

Such problems at a typewriter keyboard were noticed as early as 1926 by Klockenberg, who proposed that the keyboard be split into two halves, each angled 15° from the center line (Figure 10.21, included angle is 30°), as well as tilted laterally down (sometimes termed tented). Furthermore, Klockenberg (1926) suggested an arching of the key rows for each half of the keyboard to better configure with the natural layout of the fingers. The lateral tilting was more specifically examined by Creamer and Trumbo (1960) with a mechanical typewriter cut into two halves and tilted at five different angles. Keying at the middle position of 44° was 5% significantly faster than at the extremes of 0° (flat) or 88° (nearly vertical). Kroemer (1964, 1965, 1972) performed a more detailed analysis by varying also the upper arm position and found that the subjects preferred a similar hand orientation of 40° for the upper arms hanging down naturally. Although the subjects preferred typing on a split and tilted keyboard over a standard keyboard, typing speed did not show any differences. Error rates, however, decreased by 39%.

Further experimentation by Zipp et al. (1981, 1983) using EMG measurements of the shoulder, arm, and hand muscle indicated optimal ranges of 0 to 60° for pronation and 0 to 15° for ulnar deviation, with the standard position for keyboards of 90° pronation and 20 to 25° ulnar deviation clearly beyond the optimal range. A 13° angulation from the centerline (26° included angle) showed lower EMG than a 26° angulation. In addition, preferred lateral tilt angles of 10 to 20° were smaller than the 44° found by Kroemer (1964, 1965, 1972). Because only three subjects had been utilized in the above experiments, Nakaseko et al. (1985) performed further testing on 20 experienced typists and found similar results with subjective preferences, which led to the first commercial split model standardized at a 25° split (internal angle), a 10° lateral tilt, and a 10° horizontal tilt (far edge higher) (Buesen, 1984). Since then, several other split or tilted models have been introduced and evaluated scientifically to provide better hand and wrist postures (Gerard et al., 1994; Tittiranonda et al., 1999; Zecevic et al., 2000).

from page 506 to 507 of 〔 Biomechanics of the Upper Limbs: Mechanics, Modeling and Musculoskeletal Injuries By Andris Freivalds. @ Buy at amazon

• Great article, survey and summarize research on keyboard ergonomics. 〔The Split Keyboard: An Ergonomics Success Story by David Rempel, University of California, Berkeley, Berkeley, California. split_keyboard__david_Rempel_2008_HF.pdf

Key Switch Topic

  1. Computer Keyboard Design Flaws
  2. Guide to Keyboard Key Switch Mechanisms
  3. Mechanical Keyboard Noise Comparison
  4. What's NKRO, N-key Rollover?
  5. Blank Keycaps vs Labeled Keys
  6. Keyboard Keycaps: ABS, PBT
  7. Keyboard Key Label Printing Technologies
  8. List of Keyboards with Mechanical Switch
  9. List of Keyboards with Topre Switch
  10. Hall Effect Switch Keyboard
  11. Mechanical Keyboard: Kailh Switch
  12. Does Mechanical Keyboard Reduce Risk of Repetitive Strain Injury?
  13. List of Hardware Dvorak Layout Keyboards
  14. Programable Keyboards with Onboard Memory