Tremor and low dexterity: design a touchable safety action
An important action should work when a finger is not precise. Target size, spacing, gesture alternatives, and error recovery belong in real-device testing, without inferring a condition or promising universal accessibility.
Give the touch room
A target includes the activatable area, not only the button’s drawing. W3C gives 24×24 CSS pixels as an AA minimum with exceptions and 44×44 CSS pixels as an AAA criterion; these are screen units, not millimetres.
Leave space between actions with different consequences, especially send and cancel. Do not depend on an invisible area that people cannot understand or reach with another technology.
Separate nearby actions
Place SOS, I’m OK, and Cancel in distinguishable positions with clear labels. An orderly grid helps movement but should not turn a mistake into immediate sending.
Show recipient, consequence, and status near the control. Colour may reinforce meaning but cannot be the only distinction.
Avoid complex gestures
A precise drag, long press, or two-finger action can fail when dexterity varies. Offer a simple tap and a consistent keyboard or assistive-technology alternative.
If a gesture remains necessary, explain it first, allow time, and show an outcome. Do not hide cancellation behind a gesture.
Plan cancellation and recovery
Before sending, show confirmation and any countdown. A large, separate Cancel control should work without fine precision and say what it stops.
After sending, do not promise retroactive undo; use a separate correction. A touch mistake needs a next step, not blame.
Evaluate with practical trials
Ask people to perform real tasks with their phone, case, hand, and usual settings. Observe misses, timing, correction, and understanding without labelling the result normal or pathological.
Repeat with large text, low light, and active notifications. Record context and version: one test cannot prove accessibility for every person or situation.
Prepare another channel
If touch fails, people should know how to call, send SMS, or ask a nearby contact. Agree and practise the fallback before urgency makes searching difficult.
In immediate danger use the local number; in Europe 112 applies under country rules. An app does not replace public emergency services.
Frequently asked questions
Is making the button large enough?
No. Include spacing, clear labels, visible consequence, cancellation, and real-device testing.
Should I use a gesture to reduce taps?
Not necessarily. A complex gesture may increase errors; offer a simple tap and an accessible alternative.
Is a 44 mm target the W3C standard?
No. WCAG uses CSS pixels: 24×24 for the AA minimum with exceptions and 44×44 for AAA, not millimetres.
Sources consulted
Technical and safety information was checked against the following official sources.
- W3C: target size
- W3C: minimum contrast
- WHO: actionable communication
- European Commission: 112
- My Safe Circle: features
- My Safe Circle: Premium
Editorial note: this guide applies the W3C target criterion and actionable-communication principles to a safety action. Sources were checked on 8 September 2026; it is not a diagnosis or an accessibility guarantee.
TEST THE TOUCH
Design for a finger without perfect precision
Measure target, spacing, cancellation, and recovery on the real phone and settings.
Explore My Safe CircleThis guide covers design and testing, not diagnosis or an accessibility guarantee. In immediate danger, call the relevant local number.