# 4.1 Input and output devices for physically impaired users

An increasing amount of research has gone into making computing more accessible for people with disabilities. A user with limited movement may be able to use a joystick or a trackball to navigate a graphical user interface, and make input via programmable buttons. Ergonomic keyboards or software that converts a screen into a keyboard are now widely available.

Eye-tracker technology, which tracks the user’s eye movements across a screen and controls input, has become steadily more affordable. Also available is a ‘sip and puff’ switch that measures air-pressure changes in a tube to convert ‘sipping’ (inhaling) and ‘puffing’ (exhaling) into signals that can be used to control a mouse, joystick or keyboard.

For visually impaired users, software such as voice recognition software and screen readers can be used for input and output, and braille readers are available for tactile output to be read by users.

In the next session you will be introduced to the concept of computer systems, to help you understand how these components actually work together.

OpenLearn - An introduction to computers and computer systems
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