Phase 5: Build for a personExplainer10 min

Universal and accessible design

Designing so the widest range of people can use a thing without adaptation, and designing assistive technology with rather than for its users. The principles, the failures, and the phrase "nothing about us without us."

AssumesHuman factors and use errorSpineClinical / regulatory / human factors

You are skimming: the title, the first figure, and the short version. Switch to Read in the header for the full page, or Deep to open every deep dive.

Curb cuts were built for wheelchairs and are used by everyone with a stroller, a suitcase, or a bicycle. Captions were built for deaf viewers and are used by everyone in a noisy bar. Universal design is the observation that designing for the edge often produces the best design for the middle, and the discipline of doing it on purpose. Assistive technology is its sharp end, and it has a rule that engineers keep learning the hard way: the people you are designing for know more about the problem than you do.

The seven principles

From the Center for Universal Design in 1997, and still the reference. Equitable use: the same means of use for everyone, without segregating or stigmatizing. Flexibility: accommodates a range of abilities and preferences (left or right hand, fast or slow). Simple and intuitive: usable regardless of experience or concentration. Perceptible information: communicates in redundant modes (visual, tactile, auditory). Tolerance for error: hazardous outcomes are hard to reach and easy to undo. Low physical effort. Size and space for approach and use: reachable from a seated position, by a large or small hand.

Read your Phase 5 device against each. The speller’s grid: is it perceptible if the user’s vision is poor? The wheelchair controller: what happens if a gesture is made by accident? The adaptive switch: can a caregiver with arthritis mount it?

Predict before you look

A team designs a smart cane for blind users with a camera, an AI object recognizer, and spoken descriptions. Blind testers reject it. Why, most likely?

Nobody asked them first. Blind cane users get rich, immediate information through the cane’s tip and rely on hearing for traffic; a device that speaks over that and adds a second of latency is a step backward, however clever the recognizer. This exact product has been designed many times by sighted teams. “Nothing about us without us” is the disability community’s answer, and it is also just good engineering.

Design with, not for

Involve users from the first sketch, not the final test. Pay them for their time as you would any consultant. Let them define the problem and the success criteria. Expect your assumptions to be wrong about what is hard (usually not the thing you thought) and what is desired (usually less technology than you planned). The occupational therapist, the speech-language pathologist, and the rehabilitation engineer are professional translators between engineering and lived experience; work with them.

The abandonment problem

A third or more of assistive devices are abandoned within a year. The reasons, studied repeatedly: the device did not fit the person’s changing needs, it was hard to set up or maintain, it drew unwanted attention, it was slower than the person’s existing workaround, or the person was never consulted about its selection. Every one of those is a design or process failure. Ask, before you build: would this survive a year in a real house?

Aesthetics and dignity

Medical-looking devices get left in drawers. A hearing aid that looks like an earbud, a communication tablet that looks like a tablet, a switch housing that looks like it belongs on a gaming rig: these get used. Dignity is a design requirement. Ask the person what they want it to look like.

Cost and maintenance

A device that costs two thousand dollars serves the people whose insurance approves it. A device that costs forty dollars and can be printed at a library serves everyone else, which is most people. Makers Making Change and e-NABLE exist because of this gap. When you post an open design, include the maintenance: what breaks, how to fix it, what to keep as spares.

Stop here if you like. Seven principles, design with not for, the abandonment problem, dignity, cost. That is accessible design in ten minutes; the rest is practice with real people.

Deep dive Universal design and the mainstream 2 min

Voice assistants, screen readers built into every phone, closed captions, single-handed keyboards, dark mode, adjustable text: each began as accessibility and became a product feature everyone uses. The economics run the same way in reverse: mainstream devices with good accessibility settings often serve a disabled user better and cheaper than a dedicated assistive device. Before building a special device, check whether a phone with the right settings does the job.

Recall

Name four of the seven principles of universal design.

Equitable use, flexibility in use, simple and intuitive use, perceptible information, tolerance for error, low physical effort, size and space for approach and use (any four).

Recall

Why are a third of assistive devices abandoned within a year?

They did not fit changing needs, were hard to set up or maintain, drew unwanted attention, were slower than the existing workaround, or the user was not consulted in selecting them, all design or process failures.

Recall

What does 'nothing about us without us' require of an engineering process?

Involving the users with the disability from the first sketch as paid experts who define the problem and success criteria, rather than testing on them at the end.

Explain it to your roommate

Explain what this page was about to your roommate in three sentences. No jargon they would not know.