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 *********************