Switches
A switch is basically a device for making an electrical connection between two contacts. A mouse button can be regarded as a switch, as can a single key on a keyboard. In the context of access, a switch can be used by a person with severe and complex disabilities to help them interact with the environment. A young child may use a switch with a toy to help develop an understanding of ‘cause and effect’. A teenager may use a switch to activate an electronic communication aid or access a computer. An adult may use a switch in conjunction with an environmental control system to control devices in a house.
Choosing switches
Switches are available in a variety of shapes and sizes. Some are operated by contact (touching, pressing, squeezing, etc.); others don’t require physical contact, but can be activated by movement or sound. Switches can be operated by head, hand, arm, knee, foot, eye-blink, etc. It is important to have a proper assessment to determine the most suitable switch and the best access method. The CALL Scotland Loan Bank (link to Loan Bank) has a wide range of switches available for evaluation loans for up to two months.
Using switches with toys and household devices
Switch operated toys have a valuable role to play in introducing the concept of ‘cause and effect’, (i.e. press the switch and something nice will happen) to young children. A number of suitable toys can be purchased from e.g. Inclusive Technology, TFH and Liberator. Many simple battery-operated toys can be adapted for use with a switch by using a Battery Adaptor, available from Inclusive for £7.00. Unfortunately, an increasing number of battery-operated toys are now ‘multi-function’, with the toy performing a number of different actions, and are more difficult to adapt.
It is also possible to use a switch in conjunction with an Ablenet PowerLink or similar device to operate mains devices, e.g. a fan, a light, a tape recorder (there can be difficulties with trying to control a CD player), all of which can be motivating for people starting to use a switch.
Using switches with a communication aid
Most electronic communication aids can be set up for use with one or two switches. A person using two switches can use one switch to scan through items on a display and then use the other switch to select the desired location. A single switch user has to rely on the communication aid to scan through locations and then use their switch to select the target. It is important to have an assessment carried out by an AAC specialist to ensure that a suitable scanning method is chosen.
Using switches with a computer
The first point to remember is that you can’t plug a switch directly into a computer – you need a switch interface, available from e.g. Crick Software, Don Johnston and Inclusive Technology. There is a wide range of software available for switch users, ranging from cause and effect programs for young children, e.g. the SwitchIt! programs, through programs that support writing activities, e.g. Clicker, to programs that can provide full access to the computer, e.g. The Grid 2.
Further Information
- CALL’s 1997 book on Special Access Technology, though no longer in print, is still very relevant, particularly Chapter 10, Switches.
- The ACE Centre have a number of excellent resources and publications, including a downloadable book, Switch Access to Technology.
- ACE Centre North have a number of useful information sheets covering different aspects of the use of switches.
- The Let’s Play Project at the University of Buffalo has some excellent resources on e.g. Playing with Switches and Computer Play with Young Children with Disabilities.
- Visit supplier sites, e.g. Inclusive Technology, Liberator, QED for up to date information on switches.
