In addition to being used for pointing and selecting

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Unformatted text preview: to make this selection. Typical uses of a joystick include video games, flight simulators, training simulators, and for controlling industrial robots. Electronic Pen Another point-and-draw device is an electronic pen. In a pen-based system, you hold the pen in your hand and directly point with it on the screen to select menu items or icons; or directly draw graphics on the screen with it; or write with it on a special pad for direct input of the written information to the system. Electronic pens are of the following types: 1. Light Pen. It uses a photoelectric (light sensitive) cell and an optical lens mounted in a pen-shaped case. The photoelectric cell and lens assembly is designed in such a way that it focuses onto it any light in its field of view. Hence with this mechanism the pen can be used to indicate screen position to the computer. You operate the pen by moving its tip over the screen surface. As the light pen is moved over the screen surface, it detects the light being emitted from a limited field of view of the monitor's display. This electric response is transmitted to a processor, which can identify the menu item or icon that is triggering the photocell. In this manner, the graphics cursor automatically locks on to the position of the pen and tracks its movement over the screen. The case of the pen has a finger-operated button, which is used to select an option from the screen by clicking it. In addition to being used for pointing and selecting options from a set of options displayed on the screen, light pens are frequently used for computer-aided design (CAD) applications. For example, the user can directly draw on the screen with a light pen. By using the pen along with a keyboard, the CAD application can allow users to select different colors and line thicknesses, reduce or enlarge drawings, and add or erase graphics objects such as lines, circles, rectangles, etc. 2. Writing Pen with Pad. This type of electronic pen comes with a special type of writing pad. The pen is used to write on the pad whatever information the user wants to input to the computer system. Although this input device may app...
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This document was uploaded on 04/07/2014.

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