forum SignWriting List Forum
  Message 4264  |  Previous | Next  [ Up Thread ] Message Index
From:  Jerry Spillman
Date:  Sat Nov 18, 2000  1:29 am
Subject:  Re: touch screen


I am a member of SignWriting.  I am the owner of the Sign Bible Site and  I have some limited knowledge of the technology you are interested in, however don't know of a source to purchase from.  Below I have listed the URLs of several sites on the internet with touch-screen information.

The following is from a book I own:

"At least two methods of finger-detection have been employed.  One form relies on actual contact with the surface of the screen to capacitively detect the presence of the finger.  Another, used by Hewlett-Packard's Touch-Screen system uses a special frame around the screen.  This frame is lined on two perpendicular sides with LEDs emitting invisible light, and on the two sides opposite photodetectors.  A finger approaching the screen breaks the constant light beam and allows the computer to determine its location.

Although a very natural interface, touch screen technology suffers its own logistical problems.  As with light pens, reaching to the screen to perform normal daily work is a great way to build biceps and triceps and otherwise tire yourself out.  You're also apt to cover your screen with oily smudges and--if you share your computer with others less kempt than yourself--unknown contaminants and organisms.

The biggest problem with touch screens is the very practical matter of accuracy.  Whereas light pens can zero in on any given pixel, the touch screen is much patchier in its pointing capabilities.  The screen is divided into a checkerboard pattern with resolution of about 16x16.  Whereas the touch screen can be used for making menu choices, it is hardly adequate for drawing or graphic editing on-screen.

Touch screens have been effectively used to interface computers with a general public not versed in the intricacies of computing, enabling them to point at the function they want to carry out.  However, for skilled computer users, the touch-screen is an exotic aberration."
Quoted from The Winn L. Rosch Hardware Bible, Third Edition

These companies have touch-screens available:

I hope some of this can be helpful to you.

Jerry Spillman

Wendy Windley wrote:

val, its a add on screen for the computer that allows you to touch the screen
instead of using the mouse /keyboard....great for kids with learning
disablilities or anyone with handicapps.

happy thanksgiving

  Message 4264  |  Previous | Next  [ Up Thread ] Message Index