Now that we have covered the hardware and manufacturers that are out there, let's cover some specific models to get a better idea about the details of the technologies. This appendix focuses on a few models from Elo TouchSystems (www.elotouch.com) as this company covers each type of technology available and all its models work well on all the platforms on which the Flash authoring tools are available, with the notable exception of driver availability for Mac OS X. (See the information earlier in the chapter about Troll Touch for a touch-screen vendor who caters to Mac users and has announced a tentative release of OS X compatible drivers for its products.) The Elo TouchSystems screens plug directly into any standard VGA monitor port on a PC or Macintosh. Older Macs with built-in video cards that do not utilize the DB-15 VGA connector standard can use an inexpensive adapter to allow the connection of the touch-screen monitor cable. The touch-screen input is sent to the computer via a serial or USB connection (depending on your need and model you purchase) that plugs into your computer and with the help of a driver becomes your new mouse. Yes, you can still use your existing mouse or input device right along side of it as long as you have enough ports to connect them at the same time. This is ideal for testing your Flash application throughout the entire development process. The USB versions are also ideal for this in that you can typically have more USB devices connected to a computer than serial devices. (Another note about Troll Touch is that its products have native support for older ADB-based Macintosh computers. What better way to utilize that old Mac IIci sitting in your closet than as a touch-screen controller for your home appliances).
The installation process of the drivers is simple, and the drivers are available on the web at any time from the Elo TouchSystems web site at www.elotouch.com. Once installed, it only requires a simple restart before you calibrate and use the touch screen for input. The two types of models mentioned are differentiated in several ways. Elo offers standard CRT tubes and also flat panel LCD models. The flat LCDs are great for embedding into kiosk enclosures due to their lower heat output and smaller size. Both of those can be crucial in the design of the physical presence of your kiosk. The CRT and LCD versions are available from Elo in the four different technologies mentioned previously plus a fifth specialized version of the SAW type. Elo has a brand name associated with each type of technology to differentiate itself.
The first version we will cover in this appendix is the AccuTouch variety. The AccuTouch responds to the pressure of an object on the screen. Elo also has an infrared-based solution that stands up well to outdoor and rough use based on a technology developed by CarrollTouch. Elo acquired CarrollTouch in 1999. The CarrollTouch systems have an invisible grid of infrared light that your finger disrupts and registers as input with the monitor. These devices stand up well to heavy abuse because there is no calibration needed because the grid is always aligned with the screen. Elo's other main variety is its IntelliTouch technology, which uses surface acoustic waves (SAW) that traverse across the glass surface above the screen. In order to register a touch, your input device disrupts the waves; in this case our device is a human finger. There is also a SecureTouch, which is a variation on the IntelliTouch that adds tempered glass to resist breaking, and iTouch, which is a version of the surface acoustic wave-based screen, except that there is no glass overlay. The sound travels directly on the surface of the CRT glass, allowing the full dynamic range and viewable area of the CRT to be utilized. Each of these three technologies has their pros and cons. The author of this appendix prefers the IntelliTouch and its glass screen that can be wiped clean, its extremely long warranty, its resistance to wear and its high density of registration points. However, if you were to try and navigate or "press" with a pencil point on an IntelliTouch screen, it would not work. The point on a pencil is not large enough to disrupt the surface waves and register a touch. If you reversed the pencil and navigated with the eraser instead, the touch screen would be able to register a touch. On the flipside, the AccuTouch can be pressed with anything since it responds directly to pressure. In theory you could use any part of your anatomy to trigger the display. The AccuTouch system might be better if you determined that you would like a person to be able to use a stylus attached to your kiosk by a cable, to register his input instead of a finger. It should be noted that vendors like Troll touch and Elotouch Systems could retrofit an Apple iMac to have a built-in touch screen. These all-in-one units are ideal for educational kiosks, similar to ones you might find in a museum exhibit for children.