Switch access
From Wikipedia, the free encyclopedia
Many people with severe physical or cognitive impairment use one or more switches to access computers. A switch is an assistive technology device that replaces the need to use a computer keyboard or a mouse.
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[edit] Types of switch
Switches come in a variety of shapes and sizes depending on the action used to activate them (such as sip-puff, pushing, pulling or squeezing). Switches also vary in their colour and aesthetics and, for push switches, the amount of force required to operate them. A switch can be operated by any suitable body part that is able to produce consistent and voluntary movement.
[edit] Connecting a switch
A switch cannot be plugged directly into a computer. Instead a Switch Interface is required to bridge the gap between the switch and the computer's USB, serial, or PS/2 port.
[edit] What can be accomplished with a switch
Switches can be suitable for people with cognitive difficulties and developmental delays as they are a clear and simple tool to demonstrate action/reaction. Consequently, the activities the switch is accessing also need to be clear and simple. There are a variety of motivating switch activities that can be used to assess and develop a person's understanding of choice and timing.
People with severe physical difficulties who have good cognition are able to use the switch to attain higher level access. This is usually accomplished through scanning of an on-screen keyboard (OSK). The OSK can access any computer applications that can be accessed by a keyboard and mouse. Some can also access Voice Output Communication Aids for people with speech impairment, and Environmental Control aids.
[edit] One switch or two
Some users will prefer to use one switch, others will prefer to use two and sometimes more. For users who are using their switches to access simple activities an addional switch brings about an option of choice. It also allows two users to work collaboratively or to play against each other.
Considering multiple switch access is important for users accessing more advanced activities through scanning. This is usually determined by their physical capabilities. A single switch requires less physical control and is usually less tiring to access but it reduces scanning options and usually leads to a slower rate of input. Single switch scanning also requires much greater concentration. Two switch scanning enables a range of scanning options including row and column, and overscan. These can greatly increase input rates and can make using a computer far more comfortable and efficient.
[edit] External links
The Better Living Through Technology site contains a lot of information relating to switch access and on-screen keyboards, including reviews of OSKs, lists of switches, and information on connecting them to a computer.
Inclusive Technology are a commercial company who make many switch accessible products.
IntelliTools Inc. partnered with Madentec to develop the IntelliSwitch: a wireless switch interface with five switch ports and two built-in switches. IntelliTools is also the creator of the IntelliKeys: a programmable membrane keyboard with two switch ports. Various switch accessible educational software products are also produced by IntelliTools.
Simtech Publications is a commercial company whose line of inexpensive software focuses specifically on training single and dual switch use. They offer most of their programs as downloadable demos so you can try the programs out before buying them.
QED Ltd are a commercial company who make and sell a wide range of switches. The website contains a comprehensive list of the types of currently switches available.
