Success Criterion 2.5.4
Conformance level A

Shake-to-Undo Feature With No On-Screen Button Equivalent

2.5.4 — Motion Actuation

Scenario

Setting

A telehealth app's video-visit waiting room

What’s wrong

Shake-to-undo / shake-to-report as the only route to that function, no UI control equivalent.

Example

window.addEventListener('devicemotion', undoLastAction); // shake-only

Why it matters

People with tremor and people whose device cannot be moved freely.

How to test

Try to trigger the same function (undo, report) via an on-screen button instead of shaking the device: if no UI equivalent exists, it fails.

How to fix

A conventional on-screen control must duplicate the motion-triggered feature, and motion input must be able to be turned off. window.addEventListener('devicemotion', undoLastAction); // plus a visible Undo button doing the same thing Motion-triggered actions need a standard UI control alternative, and a way to turn motion actuation off.

Outcome

On a telehealth app's video-visit waiting room, this barrier is gone for people with tremor and people whose device cannot be moved freely — they can finish what they came here to do.

Who is affected