Touch-Based and Gesture-Based Devices

Devices and Technologies

The ubiquitous usage of touch screens in mobile computing has also resulted in a growing interest in touch screens in other devices. There is an increasing trend in exploring touch technologies for interaction with desktop computers and laptops, utilizing them on larger horizontal surfaces (e.g., to create interactive tables) and in large wall-mounted settings (e.g., to create a digital whiteboard). The success and broad user acceptance of touch interaction in mobile computing suggests that touch screens will play a bigger role in many other [Page 780]contexts and devices. Broader acceptance will depend on such things as improvements of the technology, price, and ergonomic issues in everyday usage. For example, a common ergonomic problem encountered when using a vertically mounted touch device is the feeling of arm fatigue and heaviness when used over a long period of time.

The technologies used in common consumer touch screens are either capacitive or resistive. The latter contain electrically resistive layers placed on the screen’s surface with a certain gap between them. When closing this gap by touching a point on the screen with a finger or any other object, voltage can flow between the layers, causing the system to register an input at that position. Aside from low cost, a major advantage of resistive touch screens is that they can be used with any kind of input device including gloves. This is not true for capacitive touch screens, which commonly can only be operated by plain fingers or special devices such as capacitive styli. The reason is that capacitive devices measure the distortion of the screen’s electrostatic field when touched by a human finger, which serves as an electrical conductor. One of their major advantages of capacitive devices is that they enable the integration of multi-touch technology, that is, the ability to simultaneously recognize and track multiple input points at different positions accurately at the same time.

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