Related:
- Assistive Technology (AT)
- Assistive Technology: Alternative Pointing Devices
- Assistive Technology: Braille and Low Vision Aids
- Assistive Technology: Keyboards And Other Input Alternatives
- Assistive Technology: Other Aids
- Assistive Technology Resources
- Accessible Information Technology - A case study: Part 1
- Accessible Information Technology - A case study: Part 2
- Technology for all of us
- « Web Design Article List
Assistive Technology: Keyboards And Other Input Alternatives
Contributed by Mel Pedley
Access/Ability Switches
An alternative input method that can utilise controlled movement from a foot, the head, an eyeblink or a breath.
Whilst it is possible to run a number of action switches on one system simultaneously,
usage may be restricted to switch-accessible software. Some programs offer switches as one of the input
choices. With other programs, the user can sometimes use an emulator working alongside the chosen program,
presenting the choices necessary to run the program in "switch-accessible" form.
The operation of a switch may vary according to the requirements of use. Pressing or letting go may trigger it. It
might be a latching switch that, once triggered, remains on or off until it is pressed again. Because the ability
of the user to control the switch may vary, software working with switches must be configurable to take into
account accidental or incidental pressing of the switch.
Despite the wide range of switch access routes, switch access is time consuming and can be frustrating for the user and for the listener. It is probably the last resort after all other alternatives have been considered.
- Usage:
- Users with dexterity difficulties.
- Users with physical impairments.
Braille Keyboards
A braille input keyboard can be connected to either the serial or keyboard ports on a PC. It can mimic every key on a full standard keyboard but may only allow the input of Grade 1 Braille. Its main application, therefore, is often limited to programmers using terminal emulation software.
Braille Notetakers can be attached to a desktop computer, and used to type in Grade 1 or Grade 2 Braille into the computer. This is very effective for some applications, for example word-processing. However it is necessary to have a standard keyboard attached simultaneously as the keyboard on the Notetaker cannot emulate every key combination available and the user will have to use the standard keyboard for some tasks.
Braille emulation software allows certain keys on a standard keyboard to be used as a Braille keyboard for entering text. The Alt and Ctrl keys together with a Braille letter entered on the home keys can be used to control some of the computer's functions. For example using Ctrl with P to print where P is dots 1,2,3 and 4 (s, d, f and j). Full control of the PC is not possible using this methodology.
Finally, it is possible to use Keytop Stickers to customise a standard keyboard to allow for the input of text via "braille identified" keys.
- Usage:
- Blind, or visually impaired, users.
Devices such as Braille 'n' Speak can be used to take notes which can then be read back to the user or transferred to another computer for further editing, printing or storage. The current generation of notetakers also includes modems to access the Web as well as send, and receive, email.
- Usage:
- Blind, or visually impaired users.
Ergonomic Keyboards
Ergonomic keyboards are specially designed and shaped to reduce strains, movements,
twists and tensions and thus reduce the pain and effort of typing.
In some cases the whole shape and layout of the keyboard may be radically altered.
Features can include:
- two-way tilts
- inbuilt wrist rests
- split angle key layouts
The range of ergonomic keyboards available includes:
- single handed keyboards for people with the use of only one hand
- single finger/head/mouth stick keyboards for people who do not have the use of a full hand
- expanded keyboards for physically disabled and visually impaired users
- Usage:
- Users with physical impairment.
- Users with dexterity difficulties.
Keyboard Emulation Systems
Systems where a keyboard is represented on the screen for the user to select letters by
using a cursor controlled by a mouse, pointing device, switch or switches. The keys can also
represent whole words, phrases and pictures.
- Usage:
- Users with dexterity difficulties.
- Users with learning difficulties.
Key Guards
These are rigid overlays of metal or plastic that fit over the keyboard with holes to allow access to individual keys. This makes it harder to hit the wrong key by accident and therefore enables more accurate typing. They can help in cases where users hit more keys than they want to, and also allows users to rest their hands on the keyboard while they type. Keyguards are available for most keyboards. They are inexpensive and guide a keyboard user who may have poor hand co-ordination. They can be used alongside Word Prediction Programs and standard MS Windows keypress customisation.
- Usage:
- Users with dexterity difficulties.
Keytop Stickers
Stickers allow a user to customise individual keys using Braille, enlarged or pictorial character stickers.
- Usage:
- Blind, or visually impaired, users.
- Users with learning difficulties.
Can help where a user has difficulties controlling their movements to the degree demanded by the standard keyboard. Larger keyboards are especially useful if a user uses a foot or elbow to press the keys. The keys on some keyboard may be recessed so that the user can 'dip into' them. This may be of assistance where the user suffers from athetoid movement that is forceful and jerky. As with all keyboards and pointing devices, the time that keys have to be pressed down before they register can be customised as well as the amount of time before they will register again.
- Usage:
- Users with dexterity difficulties.
Large Monitors
Increases the display size and, hence, can be used to display enlarged text and graphics.
- Usage:
- Visually impaired users.
A very small keyboard which may be of use to someone with very limited range of hand/finger movement and possibly with little strength to press keys.
The keys are usually arranged around a central space key according to frequency rather than the more usual QWERTY format. Alternatively, an organiser, such as the Psion, may be used to control a desktop computer.
- Usage:
- Users with dexterity difficulties.
Overlay & Concept Keyboards
These keyboards are comprised of a touch sensitive membrane which is divided into a
grid of up to 40000, separate, user assignable, cells. Interchangeable paper
overlays can be fitted over the membrane to indicate what function has been assigned to
each area of the keyboard. The individual membrane cells are entirely programmable
(via specialist software) and can, therefore, be adapted to the individual user's needs.
Keys can be as large or small as required. They can be positioned with large gaps between the keys and the number of keys required can be reduced or expanded as needed.
Overlay keyboards may be used in conjunction with a standard QWERTY keyboard with input being made, by a single user, from either keyboard as appropriate.
- Usage:
- Users with dexterity difficulties
- Users with learning difficulties.
Useful for inputting information when the user cannot access a standard workstation. Lightweight and battery operated. Often have a liquid crystal display and the capacity to hold approximately eight files and/or have a removable disk. Stored files can be transferred to a PC either using a removable disk as the transport medium or via direct keyboard-to- PC connection.
- Usage:
- Physically impaired users who may be unable to sit at a workstation.
Small Keyboards
The BAT Chording Keyboard
Uses seven keys that offer the same functions as a standard keyboard through multiple keystrokes. Can be held in one hand using a comfortable hand posture.
The Twiddler
A small device which is strapped to the hand.
Utilises twelve buttons and a mouse pointer.
- Usage:
- Users with dexterity difficulties.
Touch Screens
Devices which enable a use to control a computer by pointing or touching an area of the screen. Most touch screens use a clear plastic window placed in front of a standard monitor and may be used as a keyboard alternative. They should work with any mouse-driven software, but it must be remembered that mouse-driven programs are designed for small cursors rather than large fingers so, although it is a very direct method of access, some users may not be able to locate the precise, often small, areas required. Therefore, some touch screens may need to be calibrated for the individual user and/or require additional specialist software.
- Usage:
- Users with dexterity difficulties.
