>From a human factors point of view, I think this is a bad idea.
>People request an operation by pressing a switch and expect it
>to happen soon after they apply pressure.  They will be confused
>or hostile if that action occurs only when they release it.
>
I do not agree: My operator interfacing experience is with sawmill,
coal-plant, mining-machinery, and pipe-line operators. In all a fairly
though bunch. When I provide action based on button-release, it takes very
little training time to get them to understand the concept. And a very
beneficial side effect: They don't 'hammer' the button because they learn
there is nothing to be gained by pressing faster or harder! Keyboards last
longer.

Regards,

Hugo Ahrens

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Hugo Ahrens, IAI Industrial Automation Inc.
e-mail --> hahrens@direct.ca
fax    --> 604-596-3994
phone  --> 604-596-3994
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