Success Criterion 2.5.4
Conformance level A

Wave-to-Advance Camera Gesture With No Button Alternative

2.5.4 — Motion Actuation

Scenario

Setting

A ticket marketplace's seat-selection map

What’s wrong

Camera-gesture (wave to advance) features lacking button equivalents or disable toggle.

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 advance the feature via a button instead of a camera-detected wave gesture: if no button equivalent or disable toggle 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 ticket marketplace's seat-selection map, this barrier is gone for people with tremor and people whose device cannot be moved freely — they no longer have to work around this.

Who is affected