Reaction time

This tool is intended to be used as an assessment for the reaction time. It is by no means a medically accurate test and should never be treated as such.

This assessment works only on devices with an accelerometer (most phones and tablets as well as convertibles).
"Stop time on movement": Take a boxing stance and hold your phone next to your face and start the test. When you perceive the cue, make a punch with your phone as fast as possible.
"Stop time on tap": tap the screen as fast as possible once you perceive the cue.

IOS 13:
In oder to use this assessment, you have to grant permission to oritentation access

IOS 12:
If you are using the Safari browser and get a popup saying "This feature is not supported in your browser", you can enable the necessary permission in the Safari settings at "Settings > Safari > Privacy & Security > Motion and Orientation Access"

If you get a "Shake to Undo" popup you can disable this feature in "Settings > General > Accessibility > Shake to Undo".