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Choosing the Right Touch Technology
An Introduction to Touch Technology
Touch technology emerged in the early '70s. The first touch sensor, designed to sense and determine planar coordinates, was developed by Dr. Sam Hurst, a professor at the University of Kentucky and a founder of a leading touch technology company. Several years later the sensors appeared in the first touchscreen. An alternative form of user interface for computers and electronic controllers, touchscreens have been embedded in NASA spacesuits, employed where a mouse or other pointing device would be impractical, and become the interface of choice in many demanding applications and environments.
From an end-user standpoint, touchscreens offer unparalleled ease of use, speed, and accuracy, drastically reducing the time required to learn new applications or acquire proficiency with hand-held devices. For developers, designers and users, durability is an added benefit: Keyboards are more easily damaged by environmental hazards, such as liquids. And, since keyboards are fully exposed, they are more vulnerable to abuse. Mice and other pointing devices also are impractical in many environments; they are fragile, susceptible to dust and liquid, and can contribute to repetitive-motion injuries. A recent industry report reveals that keyboards are the most common device to break in kiosks. In comparison, incidents of touchscreen failure are rare; the lifecycle of a touchscreen can be measured in years, far longer than the useful life of most keyboards and mice.
Registering the Touch
Most end users are aware of minor distinctions among the various touch systems they encounter. Resistive touch is pressure sensitive and is, to use the blood analogy, the "universal recipient": any finger, pen, screwdriver, fingernail, or other probe will activate it. Infrared also registers most probes (except those that are very narrow, as is the case with some pens). Capacitive will not "trigger" unless there is body contact, so gloves and pencils will not work.
Capacitive is capable of registering the lightest touch and is especially well adapted to "swishing" for applications such as lottery or gambling machines. Surface acoustic wave must have a soft touch, so pens and fingernails will not work. Depending upon the resolution of a matrix panel, touches between active touch zones may not register.
Sometimes, especially in the case of pen entry systems, it is necessary to discriminate between a finger, palm or hand, and a stylus. Once again, only an analog resistive system is able to make the distinction.
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