Keyboard technology

The following pages outline some of technical aspects of keyboard design and operation. These articles are all a work in progress, and are subject to expansion and revision. Please bear in mind that there will be mistakes and omissions.

• Keyboard design adaptation — adaptation of the design of keyboards to suit a wide variety of uses
• Keyboard switch overview — common characteristics to aid recognition
• Switch types — details on the different switch types, e.g. mechanical, solid state
  • Conductive sensing
  • Photoelectric encoder keyboards
  • Hall effect keyboards and switches
  • Capacitive keyboards and switches
  • Membrane keyboards and switches
  • Spring-over-membrane keyboards and switches
  • Rubber domes
• Switch characteristics
  • Switch configurations — an overview of pole and throw configuration
  • Switch operating functions — alternate action, secretarial shift, double action
  • Switch design characteristics — design characteristics of keyboard switches
  • Travel — details relating to the vertical motion of keyboard switches
  • Force — details relating to the forces in play between one’s finger and the key
  • Tactile feedback
  • Keycap mounts
  • Switch lifetime
  • Comparative specifications
• Switch manufacture
• Keycap labelling
• Encoding and output — the identification and reporting of keystrokes to the host device
  • Matrix scan encoding
  • MOS/LSI single-chip encoders — single-chip keyboard encoder integrated circuits
  • MCU-based single-chip encoders — single-chip keyboard encoders built around a microcontroller
  • Rollover and lockout — definitions and implementations
• Keyboard controllers — a chip within a computer that interacts with the keyboard
• Materials
• IC date codes
• Standards
  • The great size change — widespread switch redesign at the behest of West German standardisation
  • TGL — Technische Normen, Gütevorschriften und Lieferbedingungen, the standards system of East Germany
  • Korea Certification
• Glossary
• Repairs