2.5.4 - Motion actuation
Benefits users with:
- The inability to perform particular motions (such as tilting, shaking, or gesturing) because the device may be mounted or users are physically unable to perform the necessary movement.
Intent
The intent of this success criterion is to ensure that functions triggered by moving a device (for example, shaking or tilting) or by gesturing towards the device (so that sensors like a camera can pick up and interpret the gesturing), can also be operated by more conventional user interface components.
This criterion concerns input through sensors which respond directly to motions such as gesturing towards, tilting or shaking a device. It does not cover the movement of users through space as registered by geolocation sensors or beacons, or events observed by the device other than intentional gesturing by the user. It also does not cover incidental motion associated with operating a keyboard, pointer, or assistive technology.
Ways to meet the criterion
Functionality that can be operated by device motion or user motion can also be operated by user interface components and responding to the motion can be disabled to prevent accidental actuation, except when:
- Supported interface: The motion is used to operate functionality through an accessibility supported interface.
- Essential: The motion is essential for the function and doing so would invalidate the activity.
Examples
Alternative ways are required to access instead of these actions related functionality.
Shaking
Shaking the mobile device to undo the last action such as deleting an item from a list.
A compliant application provides a mechanism to turn off the shake to undo feature.
Success
It must also provide another way to undo the last action such as adding a button.
Success
The application may provide a way to find the deleted item and to restore it.
Tilting or gesturing
Tilting the device right to advance forward and left to move backward through a sequence of steps.
Gesturing towards the user-facing camera to move forward or backward through a sequence.
Success
A compliant application provides a mechanism to turn off the shake to undo feature.
It must also provide another way to undo the last action such as adding a prev and next buttons.
Supported general and HTML techniques to meet the criterion: