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Unlike televisions, which one views passively, interactive kiosks engage the user in a two-way dialogue. The exact nature of this dialogue is determined by where, how, and why a kiosk is being used. No matter how much or how little use they may be exposed to, all interactive kiosks are subject to certain constraints such as location, ambience, and budget that will play an important role in determining how users will interface with them. There are five basic devices by which users can interact with kiosks: keyboard, mouse, trackball, touchpad, and touchscreen. A comparison of interface devices
Touchscreens
Touchscreens are currently used as the user interface on some 80% of the interactive kiosks being made today. This is mainly because the touchscreen is the simplest, easiest, and fastest way for users to tell the system what they want.There are currently four different technologies that are commonly employed in touchscreens. These are surface acoustic wave, infrared, resistive, and capacitive. Resistive touchscreens
Resistive touchscreens were the first to be developed and they are still the most widely used. A resistive touchscreen panel is composed of four layers: a conductive layer, an insulating layer, a resistive layer, and a protective layer.
Capacitive touchscreens
A capacitive touchscreen panel is coated with a material that is sensitive to electrical induction. Because living things contain electrical energy, they exhibit surface capacitance and this can be detected by the panel. (This is why you can operate a capacitive touchscreen with your bare finger but not if you're wearing gloves or with an object like a pen.)Because the capacitive layer is easily damaged, the sensitivity of capacitive touchscreens may degrade. Such screens must also be insulated from any contact with metal surfaces etc that might form an electrical ground. Infrared touchscreens
In infrared touchscreens, two or more image sensors are placed around the edges (usually the corners) of the screen. Infrared backlights are placed in the sensors' field of view on the other sides of the screen. A touch shows up as a shadow and each pair of sensors can then be triangulated to locate the touch or even measure the size of the touching object. This information is sent to the controller for processing. The advantage of infrared touchscreens is that they do not need to be calibrated the way others do. However because of the way they work, they may also detect other objects that get too close to the panel and this can cause problems.
Surface acoustic wave touchscreens
Surface acoustic wave touchscreens employ ultrasonic waves that pass over the touchscreen panel. When the panel is touched, a portion of the wave is absorbed. This change in the ultrasonic waves shows the position of the touch event and this information is sent to the controller for processing. Surface acoustic wave touchscreen panels are susceptible to damage by outside elements. Contaminants on the surface can also interfere with the functionality of the touchscreen. However an advantage of this technology is that no separate electrically or chemically sensitive layers are required in order for them to work so they are relatively easier to maintain.
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