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.(Egghead and most computer catalogs have them)
We've had great success with them.., with over 500,000 visitors a year.
They are sturdy, require little maintenance, are easy to clean and at
about $100, are affordable enough to replace one or two a year, if you
need to (but we replace about 1 out of 6 every year). We've developed a
recessed housing that they sit in, that is placed inside of a 4" deep
deck. The housing has a plexi cover, exposing only the ball, and has a
1/2" plexi rod, cut and placed to line up with which ever button you
want the visitor to access. That is...the visitor doesn't actually touch
the "mouse" button, but hits this plexi rod, and that actuates the
button. This housing restricts access at the same time as providing
controlled access.


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