Overview of Digital Accessibility Technologies | Vale.Rocks

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There are a great number of tools and devices out there designed to improve computer use for people with disabilities or even make computer use possible at all. We can consider them in two broad categories, input and output. Input methods send data provided by a user to a device, while output methods send information provided by a device to a user.

This is a non-exhaustive list of these technologies for reference. Though I have attempted to be relatively comprehensive in covering usage, accessibility often necessitates varied usage and unique assembly of technologies, such that this post does not and will not cover every case.

Screen Readers

A screen reader is an output method that audibly relays the content on a screen via non-visual methods. In addition to reading text and content that is directly upon a screen, a screen reader also often conveys semantic meaning. For example, though the word ‘navigation’ may not be displayed visually, if a section is designated as ‘navigation’, a screen reader might convey that. Screen readers are extremely configurable, like many other accessibility tools, and are commonly modified for specific user needs. Often, synthetic speech output from screen readers will be at such a pace that it cannot be comprehended by people unacquainted.

They are most commonly associated with people with visual disabilities, though are also used in many cases by people who are illiterate or have learning disabilities.

Screen Magnifiers

Screen magnifiers are an output technology which enlarge sections of a display for easier viewing. This can be achieved in technology with often toggleable enlargement of specific screen sections or with physical magnifying lenses.

Most commonly, screen magnifiers are used by people with visual impairments that are significant enough to impact computer use but which don’t necessitate a screen reader. Magnifiers are, however, also used by people who lack fine motor control and thus need enlarged inputs.

Braille Displays

Electronic braille displays, also known as refreshable braille displays or braille terminals, are dynamic braille output interfaces. Braille is a tactile writing system where characters are represented as embossed dots on a 3x2 grid known as a ‘braille cell’. Different characters have different dots within the cell embossed and in different arrangements, such that a person with a visual impairment can identify a character by feeling it with their finger.

Electronic braille displays take output from a computer and mechanically displace a surface into braille cells for the user to read. On most devices the braille is displayed in a single strip between 40 and 80 cells wide, though for mobile readers it can be narrower. Depending on the device, the current cursor location might be indicated by the dots vibrating or additional dots above or below the cell. These displays are often used for the same purpose as speech synthesisers, and sometimes both tools are used by the same individuals who switch between them depending on circumstance. Braille displays are especially valuable for people who are both deaf and blind.

Tactile Graphics Displays

Functioning very similarly to braille displays, tactile graphics displays are an output technology used to convey more graphical concepts, such as spatial layouts, charts, geometric shapes, or maps. They’re usually much denser than braille displays, with many more pins. Instead of the tactile area being a single braille cell tall, they are usually much taller. In some cases pins are not a binary flat or raised, but instead can be fixed at a range of heights so depth can be more fully conveyed.

Tactile graphics displays are mainly used by people who are blind.

Sip-and-Puff

Sip-and-puff (SNP) is an input method which sends signals based on air pressure. The user sips (inhales) or puffs (exhales) on a device with their mouth to regulate this air pressure. The device is commonly worn as a headset, but it can also be mounted directly to a surface such as a wheelchair or table. Different inputs are achieved via sips and puffs of different strengths, which are calibrated based on the individual user. These strengths are often referred to as ‘hard’ and ‘soft’.

Most users of sip-and-puff machines have severely reduced motor function.

Gyroscopic Head Mice

Often worn as an earpiece or glasses, a gyroscopic head mouse is an input device which uses head motion. Depending on the level of motor control one has, it can be used to directly control an on-screen pointer akin to a mouse, or it can be used for directional input. A tilting of the head right to indicate a right input, and so forth. It can also be used in a method more akin to a joystick, which is sometimes taken advantage of for gaming.

Ergonomic Mice

We are all familiar with the standard computer mouse, which is an input device one glides along a surface to manoeuvre a pointer....