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From: jr67960@tut.fi (J Rantala)
Newsgroups: sci.electronics
Subject: input device
Message-ID: <2300@tutor.tut.fi>
Date: 20 Oct 89 19:34:49 GMT
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Reply-To: jr67960@tut.fi (jr67960@tut.funet  uunet!mcvax!tut!jr67960)
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(This is not really my business, but I let it go anyway. Sorry if
mis-spelling english.)

Sorry if You think that this is a wrong newsgroup to this article.


Just a little background first.

I read one article (from an unrelated newsgroup), where some person was
searching a math program, which would be easy to use, "better than
paper and pencil" (with drawing capabilities). I can't be absolutely
sure, what that person accurately meant, but that did bring to my mind
the question of input devices to a computer system. I guess there is
many things which are not very easy to do with current input devices
(mouse, digitab's and what ever there is), such as free-hand
writing(!), _painting especially, and other such type works which
require very rapid but accurate() movements.

I suppose that a system which would consist of a flat screen with an
extrenal (without connecting wibers) "pencil" would be rather good, if
the flat screen would have hard covered front of it, so that it would
be possible to put it down above the table (where Your keyboard is just
now). Why(?), since then it would be possible to use it like normal book
and paper/pencil...(*)

Well, yes, there does exist "light pen" -like systems, but they are
always restrected to have physical connection (wire) to the other parts
of the system. In addition, they have a few restrictions to the
addressing methods used in the main display, and they are, basically,
not quick enough (as far as I know).

Thus, I became interested, whether there exist any other way to catch
down the position of the pen-like input device. In order to gain higher
speeds and other properties, I guess, it should (please note that, I
might be talking about something which does already exist, but anyway I
haven't heard/seen any such) be independent of the main display, but
still possible to see thrue it (since it must be directly above the main
display). But then there should be some other methods to catch the
position, than those various infrared beam systems, since it should be
possible to cover the transparent input device by whatever, without
causing any random input signals, together with great accuracy.

One possibility might be, I suppose, if there would be any way to cause
e.g. a delay to a bypassing current signal when there is a normal
network of crossing lines, vertical and horizontal lines being
separately driven (independently of each other), since then the driving
of the network would be very easy (requiring only one delay port&diode
per line) having only two input/output lines.

The point is, then, does there exist any such electrical effect
(commonly known), which can be produced via e.g. presence of external
magnetic field or low level heat or other such way, so that the
resulting effect to the electrical properties of that wire, made from
appropriate material, would be momentarily measurable in a given
position. I guess those materials used with
ferroelectric/electrochromic/cathodochromic or other variative display
systems might be just a little interesting. If that is not possible, I
guess the other way around might be the use of (digital type) switches
(color-LCD) in the place of above line, if it can be configured so that
external field can switch it off and back on, using appropriate
barriers.


(*):
The pointing device itself should have, in order to be usable, a way to
give "glitches" to a program, thus the effect should be capable to
handle different types of external field signals (the pen having, in
addition, on/off property (it's not enough to just take it away from
the panel)) in a form of different strength or so. However, that's not
needed.

It might be useful at least in character recognition (from free
hand-text in the moment when it is written down, since if the way by
which a character is written is known, it might be easier to
differentiate between characters (relative to one person in a given
time: some people like better to write down with ordinary pen than to
use keyboards, some of them being capable to write down quicker than
typewriting with a keyboard)). Thus the same input device might
possibly be used in the place of keyboard. I know that there is much
momenta against that, since the current way of thinking seems to be to
get as far from the "old" styles of producing output (pencil, paper,
etc.) as though it would be the _only "intelligent" way. In a huge
number of cases it is. But still, the most natural (and productive) way
to produce anything (in the case of human output in this era) is the
case when the position of the human hand and the look of the eyes will
match in the same place (not really, but in a brutal and violetive way
it can be said); with the mouse and keyboard system, you can't always
do your job with best benefit, at least since you must use many devices
and step between them.

What a story..


-j rantala
 5[%c\2[(7

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