Input Device

Information about Input Device

An input device is a hardware mechanism that transforms information in the external world for consumption by a computer. Often, input devices are under direct control by a human user, who uses them to communicate commands or other information to be processed by the computer, which may then transmit feedback to the user through an output device. Input and output devices together make up the hardware interface between a computer and the user or external world. Typical examples of input devices include keyboards and mice. However, there are others which provide many more degrees of freedom. In general, any sensor which monitors, scans for and accepts information from the external world can be considered an input device, whether or not the information is under the direct control of a user.

History

A definition of an input device was already included within the von Neumann architecture in 1945, however conception of an architecture including similar devices designed for input only appear since 1936. The von Neumann architecture describes a device designed for inserting user data, which are separated from the algorithm data and code. These devices included a keyboard or a punched card.

Mice were invented by Doug Engelbart in the 1960s.

Classification

Many input devices can be classified according to:-

the modality of input (e.g. mechanical motion, audio, visual, sound, etc.)
whether the input is discrete (e.g. keypresses) or continuous (e.g. a mouse's position, though digitized into a discrete quantity, is high-resolution enough to be thought of as continuous)
the number of degrees of freedom involved (e.g. many mice allow 2D positional input, but some devices allow 3D input, such as the Logitech Magellan Space Mouse)

Pointing devices, which are input devices used to specify a position in space, can further be classified according to

Whether the input is direct or indirect. With direct input, the input space coincides with the display space, i.e. pointing is done in the space where visual feedback or the cursor appears. Touchscreens and light pens involve direct input. Examples involving indirect input include the mouse and trackball.
Whether the positional information is absolute (e.g. on a touch screen) or relative (e.g. with a mouse that can be lifted and repositioned)

Note that direct input is almost necessarily absolute, but indirect input may be either absolute or relative. For example, digitizing graphics tablets that do not have an embedded screen involve indirect input, and sense absolute positions and are often run in an absolute input mode, but they may also be setup to simulate a relative input mode where the stylus or puck can be lifted and repositioned.

Early devices

Keyboards

Main article: Computer keyboard

Examples of types of keyboards include

Issues and techniques related to keyboards include

Pointing devices

An Apple pro mouse

Touchpad and a pointing stick on an IBM Laptop

A pointing device is any computer hardware component (specifically human interface device) that allows a user to input spatial (ie, continuous and multi-dimensional) data to a computer. CAD systems and graphical user interfaces (GUI) allow the user to control and provide data to the computer using physical gestures - point, click, and drag - typically by moving a hand-held mouse across the surface of the physical desktop and activating switches on the mouse. Movements of the pointing device are echoed on the screen by movements of the mouse pointer (or cursor) and other visual changes.

While the most common pointing device by far is the mouse, many more devices have been developed. However, mouse is commonly used as a metaphor for devices that move the cursor.

For most pointing devices, Fitts' law can be used to predict the speed with which users can point at a given target position.

Examples of common pointing devices include

mouse
trackball
touchpad
spaceBall - 6 degrees-of-freedom controller
touchscreen
graphics tablets (or digitizing tablet) that use a stylus
light pen
light gun
eye tracking devices
steering wheel - can be thought of as a 1D pointing device
yoke (aircraft)
jog dial - another 1D pointing device
isotonic joysticks - where the user can freely change the position of the stick, with more or less constant force
joystick
analog stick
isometric joysticks - where the user controls the stick by varying the amount of force they push with, and the position of the stick remains more or less constant
pointing stick
discrete pointing devices
directional pad - a very simple keyboard
dance pad - used to point at gross locations in space with feet

High-degree of freedom input devices

Some devices allow many continuous degrees of freedom to be input, and could sometimes be used as pointing devices, but could also be used in other ways that don't conceptually involve pointing at a location in space.

Wired glove
ShapeTape: http://www.measurand.com/products/ShapeTape.html
Some haptic devices

Composite devices

Wii Remote with attached strap

Input devices, such as buttons and joysticks, can be combined on a single physical device that could be thought of as a composite device. Many gaming devices have controllers like this.

Imaging and Video input devices

Audio input devices

Note that MIDI allows musical instruments to be used as input devices as well.

External links

Bill Buxton's extensive list of input devices http://www.billbuxton.com/InputSources.html

Hardware is a general term that refers to the physical artifacts of a technology.It may also mean the physical components of a computer system.

Hardware historically meant the metal parts and fittings that were used to make wooden products stronger, more functional, longer
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An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) to the outside world.
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keyboard is a peripheral partially modeled after the typewriter keyboard. Keyboards are designed to input text and characters, as well as to operate a computer. Physically, keyboards are an arrangement of rectangular buttons, or "keys".
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sensor is a type of transducer. Direct-indicating sensors, for example, a mercury thermometer, are human-readable. Other sensors, such as a thermocouple, only produce an output voltage or other electrical output which must be interpreted by another device (such as a computer).
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von Neumann architecture is a computer design model that uses a processing unit and a single separate storage structure to hold both instructions and data. It is named after mathematician and early computer scientist John von Neumann.
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19th century - 20th century - 21st century
1910s 1920s 1930s - 1940s - 1950s 1960s 1970s
1940 1941 1942 - 1943 - 1944 1945 1946

Year 1945 (MCMXLV
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19th century - 20th century - 21st century
1900s 1910s 1920s - 1930s - 1940s 1950s 1960s
1933 1934 1935 - 1936 - 1937 1938 1939

Year 1936 (MCMXXXVI
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punch card or punched card (or punchcard or Hollerith card or IBM card), is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions.
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Dr. Douglas C. Engelbart

Born January 30 1925 (age 82)
Portland, Oregon
Field Inventor
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cursor is an indicator used to show the position on a computer monitor or other display device that will respond to input.

In most command line interfaces, the cursor is an underscore, a solid rectangle, or a vertical line, which may be flashing or steady, indicating where
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Touchscreens are display overlays which have the ability to display and receive information on the same screen. The effect of such overlays allows a display to be used as an input device, removing the keyboard and/or the mouse as the primary input device for interacting with the
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light pen is a computer input device in the form of a light-sensitive wand used in conjunction with the computer's CRT monitor. It allows the user to point to displayed objects, or draw on the screen, in a similar way to a touch screen but with greater positional accuracy.
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A trackball is a pointing device consisting of a ball housed in a socket containing sensors to detect rotation of the ball about two axes—like an upside-down mouse with an exposed protruding ball.
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graphics tablet (or digitizing tablet, graphics pad, drawing tablet^[1]) is a computer input device that allows one to hand-draw images and graphics, similar to the way one draws images with a pencil and paper.
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unit record equipment, electric accounting machines (EAM) or tabulating machines. A data processing shop would have at least one of most of the machine types.
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keyer is a device for signaling by hand, by way of pressing one or more switches. Modern keyers typically have a large number of switches but not as many as a full-size keyboard; typically between four and fifty.
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A chorded keyboard (also called a chord keyboard or chording keyboard) is a computer input device that allows the user to enter characters or commands formed by pressing several keys together, like playing a "chord" on a piano.
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keyboard shortcut (or accelerator key, shortcut key, hot key, key binding, keybinding, key combo, etc.) is a key or set of keys that performs a predefined function.
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Command history is a common feature in operating system shells (such as Korn shell, Bash, cmd.exe, etc.), computer algebra programs, and other software that interacts with the user through a command line interface.
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Autocomplete is a feature provided by many source code text editors, word processors, and web browsers. Autocomplete involves the program predicting a word or phrase that the user wants to type in without the user actually typing it in completely.
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Autoreplace or AutoCorrect is a feature in some text editors, word processors and other programs that accept user input via keyboard. It involves automatic replacement of a particular string with another one, usually one that is longer and harder to type, as "myname" with
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IntelliSense™ is a form of automated autocompletion popularized by the Microsoft Visual Studio Integrated Development Environment. It also serves as documentation and disambiguation for variable names, functions and methods using metadata reflection.
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ShapeWriter (previously known as Shorthand-Aided Rapid Keyboarding (SHARK)), is a keyboard text input method for tablet, handheld PCs, and mobile phones invented by Shumin Zhai and Per Ola Kristensson at IBM Almaden Research Center and the Department of Computer and
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Since the Chinese language uses a logographic script — that is, a script where one or two "characters" corresponds roughly to one "word" or meaning — there are vastly more characters, or glyphs, than there are keys on a standard computer keyboard.
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