On Oct 9, 2008, at 6:40 AM, Ney, Mabel wrote:
Can anyone point me to some documentation, research or guidelines
regarding the ideal parameters for touch activation force /
sensitivity
/ pressure?
So there are two types of "sensitivity" per se. One is involves
latency and the other involves duration.
Latency is the delay (usually measured in milliseconds) between the
moment an action is initiated and the moment the effect of that action
becomes detectable. Latency should usually be as low as possible; high
latency means a noticeable pause or stammer in the activity,
especially with any animation or movement. In the world of interactive
gestures, latency usually refers to the gap between manipulating an
object and seeing it respond, especially in systems that use
projectors. There will always be some latency between the source image
(on the computer) and the displayed image (on a projector/screen), but
a latency under 20ms is ideal, as the system will seem very responsive
to user input.
The other kind of sensitivity involves duration: How much time is
required with a finger touch before the system registers a touch event
and executes an action? This can vary by audience and by the type of
touchscreen it is (capacitive, acoustic surface, infrared, and
resistive). For a public kiosk, you may want very deliberate, long
taps (50ms+), but in general a 20ms+ touch is going to be fine. For
personal devices you may want to allow users to adjust the sensitivity
themselves.
You might want to throw out anything under 20ms to account for
accidental touches or brushes with a finger (or in some cases, a
sleeve).
It's also good practice to have the trigger for actions be onRelease
instead of onPress. Gives the user time when their finger is on a
button to move it off (and thus not trigger the onRelease) for self-
correction of errors.
Dan
Dan Saffer
Principal, Kicker Studio
http://www.kickerstudio.com
http://www.odannyboy.com
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