Is an input device that contains keys you press to enter data and instructions into a computer or mobile device?

Describe several types of computer input devices, giving examples of their use.

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modality of input (e.g. mechanical motion, audio, visual, etc.)
the input is discrete (e.g. key presses) or continuous (e.g. a mouse's position, though digitized into a discrete quantity, is fast enough to be considered continuous)
the number of degrees of freedom involved (e.g. two-dimensional traditional mice, or three-dimensional navigators designed for CAD applications)

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 pointer appears. Touch-screens 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)

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 set up to simulate a relative input mode like that of a touchpad, where the stylus or puck can be lifted and repositioned.

Input and output devices make up the hardware interface between a computer and a scanner or 6DOF controller.

A keyboard is an input devices that contains keys users press to enter data and instructions into a computer.
Most desktop computer keyboards have:

The insertion point, also known as the cursor, is a symbol on the screen that indicates where the next character you type will appear.
An ergonomic keyboard has a design that reduces the chance of wrist and hand injuries
Ergonomic incorporates comfort,efficiency, and safety into the design of the workplace.
Keyboards on mobile devices typically are smaller and/or have fewer keys.
Some phones have predictive text input, which saves time when entering text using the phone's keypad.

http://digitalunite.com/sites/default/files/images/keyboard850.jpg

An object used as a pointing and drawing device. The mouse usually has a ball and buttons and is connected to the system unit through serial port. As a mouse is rolled across the flat desktop in any direction, it locates the pointer correspondingly on the screen. Then it issues commands using the selection buttons on the mouse. Many portable microcomputers such as lap-tops use track balls instead of mice.

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A touchpad is a small, flat, rectangular pointing device that is sensitive to pressure and motion.
A touchpad or trackpad is a pointing device featuring a tactile sensor, a specialized surface that can translate the motion and position of a user's fingers to a relative position on screen. Touchpads are a common feature of laptop computers, and are also used as a substitute for a mouse where desk space is scarce. Because they vary in size, they can also be found on personal digital assistants (PDAs) and some portable media players. Wireless touchpads are also available as detached accessories.

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A touchscreen is an electronic visual display that the user can control through simple or multi-touch gestures by touching the screen with one or more fingers. Some touch screens can also detect objects such as a stylus or ordinary or specially coated gloves. The user can use the touchscreen to react to what is displayed and to control how it is displayed (for example by zooming the text size).
The touchscreen enables the user to interact directly with what is displayed, rather than using a mouse, touchpad, or any other intermediate device (other than a stylus, which is optional for most modern touchscreens).
Touchscreens are common in devices such as game consoles, all-in-one computers, tablet computers, and smartphones. They can also be attached to computers or, as terminals, to networks. They also play a prominent role in the design of digital appliances such as personal digital assistants (PDAs),satellite navigation devices, mobile phones, and video games.
The popularity of smartphones, tablets, and many types of information appliances is driving the demand and acceptance of common touchscreens for portable and functional electronics. Touchscreens are popular in the medical field and in heavy industry, as well as in kiosks such as museum displays or room automation, where keyboard and mouse systems do not allow a suitably intuitive, rapid, or accurate interaction by the user with the display's content.

With pen input, you touch a stylus or digital pen on a flat surface to write, draw, or make selections.
Pen input also used to refer to the usage of mobile devices such as wireless tablet personal computers, PDAs and GPS receivers. The term has been used to refer to the usage of any product allowing for mobile communication.
An indication of such a device is a stylus, generally used to press upon a graphics tablet or touchscreen, as opposed to using a more traditional interface such as a keyboard, keypad, mouse or touchpad.

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A scanner is a device that reads spatial pattern such as images, graphics and texts, and then generates digital signals of that pattern. Converted digital data may be processed by a computer, stored in a disk, printed by a printer or displayed on a monitor. Scanners are commonly used to capture graphic images that can then be placed in a page or on any document.
Scanners usually include:

optical character recognition (OCR) software - scanners can read and capture texts directly through optical scanning.
optical mark recognition(OMR) software - scanners can reads hand-drawn marks such as small circles or rectangles.
The optical scanner is called a bar code reader. A bar code is a specialized code represented by sets of parallel bars of varying thickness and separation. This is used for fast identification of items with an optimal scanner. The bar code reader is a photoelectric scanner that read the bar code.
magnetic stripe card readers read the magnetic stripe on the back of cards such as:

magnetic ink character recognition (MICR) devices read text printed with magnetized ink.
An MICR reader converts MICR characters into a form the computer can process.
Banking industry uses MICR for check processing.