I am suprised to see Peter's endorsement of trackballs.  With 500k/yr.
visitation, I figured that MD Science Center would have continual problems
keeping trackballs running, particulary retail versions.  I am glad that
they seem to work well for you.  As I am partial to touch screens myself, I
have a couple points to ponder regarding trackballs and wondered how the
list felt on the issue of what is an appropriate user interface mechanism
for a public computer station.

What impact does the mechanical user interface have on an exhibits ability
to educate?

Despite the increasing popularity of computers, many people are still
nervous about using them.  Previous negative personal experience or lack of
experience can cause a visitor to think twice before approaching a computer
station.  I remember teaching my mom to use the mouse on her computer and
even though I take the skills needed to associate the cursor with the
mouse/trackball position for granted, she was often confused as the pointer
location, velocity and unusual hand motions made it difficult for her to
understand what she had to do to complete a task.  From my observations,
some visitors may approach a computer due to their interest on what is on
the screen, but then become discouraged with operating the system.  Even
the most primitive input via keyboard can be frustrating if the user is not
familiar with keyboard layout and has to hunt for every key.

My personal/professional conclusion (which I am opening up to debate) is
that a touch screen provides the ideal user interface from the visitor's
point of view.  People use their fingers to direct attention and are
trained from birth to use them for making selections.  Children's toys,
elevators, radio's, TV... common items that are used by everyone rely on
the point and touch method of selection.  This is one reason that the touch
screen is probably the best user-interface around.  A simple caption on the
opening screen suffices to show the visitor how to make choices.  I have
observed visitors go up to a system, and with no direction, touch the
screen as a natural act of pointing.  And in that brief moment, BINGO!,
they realize that they are operating the computer and know how to proceed.
A mouse or trackball would require positioning the cursor, then clicking
the appropriate button before any results are seen.

Once you have removed the "operating barrier", the visitor can focus their
attention on content.  I feel that a touch screen system would convey
information better than another type of interface.  (Also, open to
debate... any studies on this?)

From a design standpoint, you can be more creative with how a visitor
interacts with a touch screen system.  You could use the direct contact
with "objects" on the screen to reinforce cause and effect relationships.
 Use can also use visual design principles to associate colors, icons, etc.
with functions to make it easy for the visitor to understand what action to
take to make a selection.

The down side is that a touch screen monitor (which are manufactured by
many different companies for MAC and PC) is an expensive investment.  If
money is the only criteria that you use to evaluate an exhibit under
development, then go trackball.  However, if you look ahead to how
effective the exhibit will be you might consider the extra investment
worthwile.

Which finally brings me to the maintenance and maintenance cost issue.  I
have been responsible for design and maintenance of exhibit computer
systems with and without touch screens and when I install a touch screen
system, thats the last I have to mess with it.  There's nothing on it for
the visitor to break.  Maintenance cost = $0.00.  Warranty = 3 yrs.
 Depending on your visitation level and geographic area, a trackball will
require more maintenance and even though the initial expense is lower at
Peter's cost of $100.00 the cost difference between touch and trackball is
slowly eroded away.  Another important maintenance factor which will vary
between facilities is how soon does your exhibits/maintenance staff figure
out that a trackball is acting goofy beacase it's dirty.  How many visitors
are frustrated by a jumpy mouse pointer before your staff notices this,
cleans the mouse and remedies the situation.

If you are wondering how geographic area has an effect on trackball
operation... well, I used to work at the Virginia Marine Science Museum (at
that time, visitation 360k to 400k).  The museum was a popular stop for
beach visitors especially on rainy days when they were chased from the
beach into our front doors.  Even the visitors that were nice enough to
shower before they came over would have sand in their hair (head, arms,
eyebrows).  If you have ever dealt with sand, you know that it has a much
greater destructive power than mere dirt or dust.  In other words, some
facilities may not enjoy performance from trackballs at the level enjoyed
by the MD Science Center.  I think it's great they work so well there.

Finally I just want to say that my company does not manufacture or act as a
distributor for touch screen monitors.  The exhibit computer systems and
software developed by Freya Ventures incorporate a touch screen monitor for
the reasons outlined above.

        Mark C. Vang : Freya Ventures : (757) 340-0099
                2100 Mediterranean Ave. Suite 15
                   Virginia Beach, VA 23451
>   [log in to unmask]    :    [log in to unmask]      <
* Interactive touch screen exhibit software/systems and exhibit  *
* technology integration for Museums, Science Centers, Aquariums *




******************
Date:    Thu, 30 Jan 1997 21:03:42 -0500
From:    Shrope/Ratcliffe <[log in to unmask]>
Subject: Re: Trackballs

We've been using the Kensington Trackball (for Mac and PC) for all our
on-floor computer exhibits for over 7 years, at the Maryland Science
Center in Baltimore.

Peter Shrope
Exhibit Manager, MD Science Center
email: [log in to unmask], or reply to the above
*********************