In-range, locked, and fired must be separately legible once contact is gone

What it is

After contact is gone, people need to know which of at least three moments they are in: in range (the hand is seen, they may start), locked (a target or command is captured, not yet committed), fired (the event has committed). If the three share one flash, people cannot tell whether to keep approaching, to hold, or to drop the hand. What is required here is that, as a substitute for contact, the states must come apart. How many colours, how many sounds, how transitions look, is the next layer of feedback encoding. It cannot be smuggled through under “is there feedback.”

Why it happens

Contact devices encode the three steps in physics: a hand over a trackpad is approach, press is lock, bottom-click is fire. Mid-air turns all three into inferences that have to be displayed. Feedback only at fire leaves in-range and locked silent, so people fire before lock or keep holding after fire. Feedback only on entering range makes people think they already clicked. Each state licenses a different next action, so feedback must make the next action decidable. Pinch's enter / hold / release is three states on the action side. They should align with these system-side states, but they must not impersonate them: the action may have entered while the system has not locked.

Studying it

Build a task that needs all three steps: place the hand where it can be seen, aim at a target, then confirm. Turn off feedback for one state at a time and watch error types: firing out of range, dropping before lock, retrying after fire. The measure is error-type counts, not a total. Control with mouse hover-press-release. Do not use a yes/no “did you see feedback”; that does not measure distinguishability.

Where it stops holding

A global toggle with no target aiming can fold lock into fire; two states suffice. Continuous drag stretches lock and postpones fire until release; the time mix changes, the three meanings remain. With gaze aiming, “in range” may become “gaze on target”; the channel changed, it still has to come apart from lock and fire. Making all three loud is noisy. Distinguishable does not mean equally theatrical. Weak in-range, medium lock, strong fire is a common allocation; the encoding itself belongs to the later layer.

Applying it

• List the next action for in-range, locked, and fired, and give each next action a unique signal.
• Ban one flash covering all three. At least let fire differ in channel or temporal pattern from the first two.
• Accept by injecting “pinch before the hand is seen,” “drop as soon as it aims,” “keep pinching after it clicked.” Check that people correct by state, not by doing the whole thing again.

Related

• Same group: C4.11.1 Mid-air gestures have no natural contact feedback · C4.11.3 Continuous action needs continuous feedback, not only an end bell · C4.11.4 Primary states need at least one non-visual channel
• Adjacent: C4.26 Distinguishing three-state feedback · C4.06 Air pinch
• Search: hover lock fire · three-state input · state feedback