Accessible Interval Timer Setup Checklist

An interval timer should not depend on one signal. If the only cue is color, it can fail in bright light or for someone with color-vision differences. If the only cue is sound, it can fail in a noisy room or for someone who cannot hear it. I configure important transitions with at least two forms of feedback.

This checklist covers the timer setup itself. It does not claim that every browser and assistive-technology combination behaves identically, so test the finished routine with the person and device that will use it.

Use names that work without color

Name intervals by action rather than color or position:

• Better: “Seated row — left”
• Less clear: “Blue exercise”
• Better: “Rest — prepare to stand”
• Less clear: “Next one”

The name should explain the current action when read on its own. That helps visual scanning, voice cues, shared routines, and screen-reader navigation.

Pair visual and audio cues

For each important state, provide two signals when possible:

Do not distinguish “rest” and “finished” with pitch alone if a voice cue can say the state directly. The completion cue should be unmistakable when the screen is out of view.

Check contrast in the real environment

A timer that looks clear at a desk may be hard to read across a room. Test it at the distance and lighting used during the session.

• Increase browser or operating-system text size if labels are small.
• Use light or dark mode based on the room, not habit.
• Avoid relying on subtle gray differences for the active phase.
• Put the device where reflections do not cover the countdown.
• Confirm that current and next exercise names remain readable.

The Web Content Accessibility Guidelines explain that color should not be the only visual means of conveying information and provide contrast criteria for text. See W3C WCAG: Use of Color and Contrast Minimum.

Make touch targets forgiving

During exercise, precision is lower than when sitting at a desk. Before the session:

• Check that Start, Pause, Resume, and Stop can be reached with one hand.
• Avoid placing the phone where an accidental touch is likely.
• Test pause and resume before the real routine.
• Use fullscreen only after confirming how to exit it.
• Keep emergency or assistance controls outside the timer interaction.

If another person operates the timer, agree on whether tapping the timer pauses it so that an attempted screen read does not change the session unexpectedly.

Reduce unnecessary motion

Movement in the interface should support the task, not compete with it. Use the browser or operating system's reduced-motion preference when animation makes it harder to focus. A changing numeric countdown and text label should still communicate the phase without decorative motion.

Test orientation changes as well. Locking a phone to portrait can prevent the timer from rotating when the device is moved, but use the orientation that keeps the controls and current phase easiest to see.

Prepare for hearing differences and noisy rooms

Sound cues need a visual equivalent. In a loud gym, voice prompts may be clearer than short tones; in a quiet therapy space, a lower-volume tone may be less disruptive.

• Preview every cue at the intended volume.
• Use short, distinct phrases such as “rest,” “change sides,” and “finished.”
• Keep voice recordings free of unnecessary detail.
• Check whether headphones are safe for the activity and environment.
• Never make a safety-critical instruction depend only on timer audio.

For device-specific troubleshooting, use the Browser Interval Timer Sound Checklist.

Test the routine, not just the settings

Run a compressed version with five-second intervals. Ask the person using it to identify the current phase without help. Then test pause, resume, a missed cue, and completion.

Record concrete problems:

• “The rest and completion tones sound the same from across the room.”
• “The exercise name wraps and the side is hidden.”
• “Pause is difficult to reach with the phone mounted.”

Those observations lead to specific fixes. “Make it more accessible” does not.

Final pre-session checklist

• Every interval has a descriptive name.
• Important transitions use more than color alone.
• Sound is not the only way to understand state.
• Text is readable at the actual viewing distance.
• Start, pause, resume, and stop have been tested.
• A short end-to-end rehearsal completed successfully.

Once the checklist passes, build the full routine and save the tested configuration so the same accessible setup can be reused.