Success Criterion 2.5.4
Conformance level A

Tilt-Based Scrolling With No Conventional Control Option

2.5.4 — Motion Actuation

Scenario

Setting

A fitness app's workout tracker

What’s wrong

Tilt-based scrolling/parallax input without a conventional control.

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 scroll/trigger parallax via a conventional control instead of tilting: if tilt is the only input method, 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 fitness app's workout tracker, this barrier is gone for people with tremor and people whose device cannot be moved freely — they reach the same outcome without extra effort.

Who is affected