Usability for Nerds/Accessibility to handicapped users
Some countries have laws requiring that devices should be accessible to handicapped users. You shouldn't think of this as an isolated problem, because making a device easier to use for handicapped people may also make it easier to use for able-bodied people. Remember that even if people are not handicapped, they may not be as agile as you are. Children have less physical strength and old people may have less precise movements, reduced hearing and reduced vision.
Some of the handicaps you may consider are:
- missing or paralyzed limbs
- impaired motor skills, shaking or imprecise movements
- impaired hearing
- reduced vision, blindness or color blindness
- reduced cognitive skills
All mechanical devices, like buttons, handles etc., should have sufficient size and not require small, precise movements.
Displays should also have sufficient size, and the details should not be too small. There should be an appreciable difference in luminance between background and text, as well as other figures that need to be distinguished. A difference in color is not sufficient.
All software should be designed so that it can be used without a mouse.
Blind people have reading aids that translate text into synthetic speech or Braille code. In order to support such technical aids, you should design web pages and other text files so that they make sense when read as plain text. All images that contain important information should have an alternative text behind them. Avoid flashing, flickering and animated text and figures. See the page on making web sites accessible for more information.
See the list of recommended web sites for references on how to make things accessible.