input device, peripheral, data, information processing system, appliance, keyboard,mouse,scanner, digital camera, joystick,human interface device, layout of buttons, key, character, computer, spring-based buttons, virtual key, projected keyboard, symbol, letters, numbers or signs, execute computer commands, touchscreen, pen device, character recognition, voice recognition, text, numbers, word processor, text editor, program, software, computer gaming, gaming features, keystroke combinations, commands, operating system of a computer, Control-Alt-Delete combination, task window, shut down, machine, command-line interface, user interface, objects, computer monitor, flat surface, pointer, screen, primary and secondary button, index finger, scroll wheel, to scroll, rubber ball, advantages, disadvantage, clog, optical sensors, coloured light, wireless transmission, radio, infra-red mice, wired mice, number of applications, keyboard input, programmers, power users, manipulation of graphics, laptop computers, 'nipple', trackball, photograph, printed text, handwriting, ornament, digital image, desktop (or flatbed) scanner, hand-held scanners, high-quality image, image sensor, drum scanner, photomultiplier tube, charge-coupled device, Contact Image Sensor, rotary scanner, high-speed document scanning, photomultiplier, planetary scanners, 3D scanners, three-dimensional models of objects, digital camera scanners, reprographic cameras, resolution, anti-shake, digital cameras, traditional scanners, distortion, reflections, shadows, low contrast, digital cameras, speed, portability, gentle digitizing, full-colour, photo-realistic 3D models of objects, PDAs, video, camera phone,mobile phones, digital and film cameras, optical system, lens, variable diaphragm, focus light, image pickup device, diaphragm, shutter, amount of light, imager, film, image pickup device, film, cameras, digital cameras, display images, screen, recorded, store, delete, memory, moving video with sound, elementary image editing, stick, pivots, angle, direction, control column, principal control device, military aircraft, aircraft's flight, video games, console, analogue stick, controlling machines, cranes, trucks, underwater unmanned vehicles, wheelchairs, surveillance cameras, zero turning radius lawn mowers, miniature finger-operated joysticks, smaller electronic equipment
Exercise 3. What do you know about these notions?
Exercise 4. Read the text and answer the questions following it.
Text Input devices
In computing, an input device is any peripheral used to provide data and control signals to an information processing system such as a computer or other information appliance. Examples of input devices include keyboards, mouse, scanners, digital cameras and joysticks.
A ' keyboard ' is a human interface device which is represented as a layout of buttons. Each button, or key, can be used to either input a linguistic character to a computer, or to call upon a particular function of the computer. Traditional keyboards use spring-based buttons, though newer variations employ virtual keys, or even projected keyboards.
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A keyboard typically has characters engraved or printed on the keys and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence. While most keyboard keys produce letters, numbers or signs (characters), other keys or simultaneous key presses can produce actions or execute computer commands.
Despite the development of alternative input devices, such as the mouse, touchscreen, pen devices, character recognition and voice recognition, the keyboard remains the most commonly used and most versatile device used for direct (human) input into computers.
In normal usage, the keyboard is used to type text and numbers into a word processor, text editor or other programs. In a modern computer, the interpretation of key presses is generally left to the software. A computer keyboard distinguishes each physical key from every other and reports all key presses to the controlling software. Keyboards are also used for computer gaming, either with regular keyboards or by using keyboards with special gaming features, which can expedite frequently used keystroke combinations. A keyboard is also used to give commands to the operating system of a computer, such as Windows' Control-Alt-Delete combination, which brings up a task window or shuts down the machine. A command-line interface is a type of user interface operated entirely through a keyboard, or another device performing the function of one.
A computer mouse is a device used for pointing to objects on a computer monitor, and selecting them. It can be moved around on a flat surface. Those movements are transmitted back to the computer and move a pointer on the screen in the same direction. The mouse usually has one or more that can be pressed to select items on the screen and execute commands. On most modern mice, one finds at least a primary and secondary button, and often third or fourth buttons. The primary button is designed to be used with the index finger, while other buttons are often positioned to be used with the other fingers. Many mice also contain a scroll wheel, which can be used to scroll in documents.
Up until a few years ago, mice tended to be made by having a rubber ball that would roll around and move sensors inside the mouse. These had one major disadvantage: the ball picked up dirt, which could clog the sensors, and which required periodic cleaning. Today, these have mostly been replaced with optical sensors, which emit a coloured light (usually red) and measure the reflections from the mouse surface to determine movement. Mice today are now available that use wireless transmission -usually radio, sometimes Bluetooth, and occasionally infra-red, and wired mice are now extremely cheap to purchase.
Despite their prevalence, not all tasks can be best accomplished using the mouse - there are still a number of applications optimized for keyboard input (especially command line applications), and many of these tend to be preferred by programmers, power users and those who have learned how to touch type. For other tasks, especially involving the manipulation of graphics, the mouse is unavoidable. On laptop computers, track pads are often provided in place of the mouse, although some laptops provided a small rubber 'track point' (sometimes referred to as a 'nipple'). Trackballs are occasionally used in place of mice.
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In computing, a scanner is a device which analyses a physical image (such as a photograph, printed text, or handwriting) or an object (such as ornament) and converts it to a digital image.
Most scanners today are variations on the desktop (or flatbed) scanner. Hand-held scanners, where the device is moved by hand, were briefly popular but are now not used due to the impossibility of obtaining a high-quality image. Both these types of scanners use a CCD as the image sensor, whereas a drum scanner uses a photomultiplier tube (PMT) as the image sensor.
Modern scanners typically use a charge-coupled device (CCD) or a Contact Image Sensor (CIS) as the image sensor, whereas older drum scanners use a photomultiplier tube as the image sensor. A rotary scanner, used for high-speed document scanning, is another type of drum scanner, using a CCD array instead of a photomultiplier. Other types of scanners are planetary scanners, which take photographs of books and documents, and 3D scanners, for producing three-dimensional models of objects.
Another category of scanner is digital camera scanners, which are based on the concept of reprographic cameras. Due to increasing resolution and new features such as anti-shake, digital cameras have become an attractive alternative to regular scanners. While still having disadvantages compared to traditional scanners (such as distortion, reflections, shadows, low contrast), digital cameras offer advantages such as speed, portability and gentle digitizing of thick documents without damaging the book spine. New scanning technologies are combining 3D scanners with digital cameras to create full-colour, photo-realistic 3D models of objects.
A digital camera (or digicam) is a camera that encodes digital images and videos digitally and stores them for later reproduction. Most cameras sold today are digital, and digital cameras are incorporated into many devices ranging from PDAs and mobile phones (called camera phones) to vehicles.
Digital and film cameras share an optical system, typically using a lens with a variable diaphragm to focus light onto an image pickup device. The diaphragm and shutter admit the correct amount of light to the imager, just as with film but the image pickup device is electronic rather than chemical. However, unlike film cameras, digital cameras can display images on a screen immediately after being recorded, and store and delete images from memory. Many digital cameras can also record moving video with sound. Some digital cameras can crop and stitch pictures and perform other elementary image editing.
A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal control device in the cockpit of many civilian and military aircraft, either as a center stick or side-stick. It often has supplementary switches to control various aspects of the aircraft's flight.
Joysticks are often used to control video games, and usually have one or more push-buttons whose state can also be read by the computer. A popular variation of the joystick used on modern video game consoles is the analogue stick. Joysticks are also used for controlling machines such as cranes, trucks, underwater unmanned vehicles, wheelchairs, surveillance cameras, and zero turning radius lawn mowers. Miniature finger-operated joysticks have been adopted as input devices for smaller electronic equipment such as mobile phones.
