An alternative input device is a type of assistive technology that replaces a mouse or keyboard (or both), enabling a person with disabilities to use a computer.
Various types of hardware and software input devices are available (and in all likelihood, you’ve probably used at least one of them). In this article, we’ll discuss several examples.
Examples of Alternative Input Devices
Broadly speaking, “alternative input devices" can include common input-output devices like touchscreens and on-screen keyboards.
Most people are familiar with the basic features of those systems, so we’ll focus on assistive technologies (AT) that are built specifically for computer users with disabilities.
To meet the requirements of the Americans with Disabilities Act (ADA) and other non-discrimination laws, you’ll need to make sure that your online content works with various types of AT — and fortunately, this is an achievable goal. Here’s what you need to know.
Also called eye trackers, eye-tracking systems are intended for people with conditions that limit their mobility. Users can control on-screen keyboards and select interactive elements by looking at specific parts of the screen.
In other words, the user navigates and “clicks" using their eyes. Eye-tracking systems require concentration, and using them for long periods of time can be exhausting — but when websites are designed with accessibility in mind, they provide a more comfortable experience for eye-tracker users.
Related: Creating Accessible Content for People Who Use Eye-Tracking Devices
Sip-and-puff (SNP) devices enable people to “sip" or “blow" air into a wand, which activates a switch. Specialized software translates the signal from the switch to trigger commands.
SNP systems can be expensive, but they’re not just for computers; people who do not have the use of their hands may also use an SNP interface to control wheelchairs and other electronic devices.
Related: Understanding Assistive Technologies: What Are Sip-and-Puff Systems?
As the name implies, a head mouse (also known as a head pointer) translates the movements of the user’s head into mouse movements.
For accurate movement tracking, the system may use a camera or a hardware headband. Some head mouse systems can be combined with touchscreens to give the user more control.
“Modified keyboard" is a catch-all term for keyboards that accommodate a wide variety of abilities and conditions. Keyboards may have larger keys, color-coded keys, or a smaller form factor, depending on their intended use.
Software keyboards (also called keyboard emulators) may also be considered “modified keyboards,” though software keyboards may be directly operated with a mouse, touchscreen, or other types of AT.
Related: Using Keyboard Emulators to Access the Web
A joystick may provide some users with more precise control than a standard mouse, particularly if the individual has tremors or other motor control issues. The joystick typically moves an on-screen pointer, and the user can “click" on elements by using their keyboard or buttons on the joystick.
How Web Accessibility Improves Experiences for AT Users
The Web Content Accessibility Guidelines (WCAG) is widely considered the international standard for digital accessibility. One of the core principles of WCAG is operability: Content cannot require a type of interaction that the user cannot perform.
Websites and mobile apps may create barriers for AT users in a number of ways, and WCAG addresses these barriers through simple rules. For example:
- WCAG 2.1 Success Criterion (SC) 2.5.1, “Pointer Gestures" requires that all functionality that uses multipoint or path-based gestures can be operated with a single pointer. This accommodates eye-tracking systems and other alternative input devices.
- WCAG 2.1 SC 2.4.3, “Focus Order" requires that focusable components receive focus in an order that preserves meaning and operability. This reduces potential confusion for people who use a keyboard (or modified keyboard) for navigation.
- WCAG 2.1 SC 2.5.2, “Pointer Cancellation” requires that when functionality can be operated with a single pointer, the down-event of the pointer (such as the down-click of a mouse) is not used to execute any part of the function. This reduces accidental “clicks" when using AT.
- WCAG 2.1 Guideline 2.2, “Enough Time,” includes several requirements for avoiding arbitrary time limits and giving users ways to extend their sessions. Many AT users need more time to complete tasks, and limiting time limits enables these people to browse at a comfortable pace.
This is not a complete list — WCAG includes many success criteria intended to improve experiences for AT users.
Related: Why Developers Must Consider Alternate Input Devices for Web Accessibility
Developing Better Content by Prioritizing Web Accessibility
By thinking about how your users experience your content, you can improve experiences for every user. That includes people who use a traditional keyboard and mouse to browse your content; WCAG’s requirements are closely aligned with the best practices of web design.
Of course, it’s much easier to develop accessible content if you incorporate the principles of inclusive design into the product development process. To learn more, download our free eBook: Developing the Accessibility Mindset.