INPUT DEVICES
Input devices are the means by which data/information is sent into the
computer. They translate between the users natural language and the electronic
signals needed by the central language and the electronic signals needed by the
central processing unit, consisting of the processor and the main memory.
Over the years, there has been developments and improvements in the way
data are sent into the computer for processing, beginning from the keyboard in
the early days of computer systems unto voice recognition of recent days.
1.
Keyboard and Pointing Devices (e.g Mouse,
Joystick, e.t.c)
A keyboard and mouse are commonly used input
devices in office systems, in conjuction with Visual Display Units (VDUS). Many
office workers including managers have a personal computer (PC) or other
terminals on their desk top, with keyboard and mouse (of track balls) and the
VDU for input and output.
A pointing device is
any human interface device that allows a user to input spatial data to a
computer. In the case of mice and touch screens, this is usually achieved by
detecting movement across a physical surface. Analog devices, such as 3D mice, joysticks,
or pointing
sticks, function by reporting their angle of deflection.
Movements of the pointing device are echoed on the screen by movements of the pointer,
creating a simple, intuitive way to navigate a computer's GUI.
Using a mouse is usually quicker than a keyboard
and input errors are fewer when the computer system provides a graphical user
interface (GUI).
This is a way of processing data and
information to users and offering processing choices to users, in the form of
an easy-to- understand graphical presentation on screen.
Although it is now usual for computer systems
to have a GUI, the term originated because
interaction between a
computer user and the computer at one time was by text-and- keyboard
interactions. GUI, in contrast, uses graphical displays and pull-down menus,
which the computer user can control with a mouse for example, computer users
have grown accustomed to WIMP computer system design. WIMP stands for either
Windows, Icons, Mouse and pointer or Windows, Icons, Mouse and pull- down
menus.
However, both keyboard and mouse Input are
slow methods of input, since they are dependent on the speed of the human
operator. They are inappropriate in put
devices for high volume, high –speed automated processing system and, where
possible, faster input methods should be preferred.
2.
BAR COD READER
A bar code is a pattern of black and white
stripes representing a code, often an inventory item code. The code is read by
a scanner or light pen, which converts the bar code image into an electronic
form acceptable to the computer. Bar codes are used widely at check points in
supermarkets and shops (electronic point of sale systems or EPOS systems). They
allow the point of sale system to recognize the item being purchased and to add
its price to the customer’s total bill. They speed up the check out process and
reduce the risk of input error by the checkout clerk.
3.
EFTPOS
Another input method associated with EPOS is
EFTPOS-electronic funds transfer at point of sale. This system allows a
customer to pay for their purchases using a magnetic stripe or chip and pin
card by their card being read by a card reader at the supermarket checkout.
Funds are then transferred from the customer’s debit or credit card account to
the supermarket electronically.
4.
Scanner
In computing, an image scanner—often
abbreviated to just scanner—is a device that optically scans images,
printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are
variations of the desktop (or flatbed) scanner where the document is
placed on a glass window for scanning. Hand-held scanners, where the
device is moved by hand, have evolved from text scanning "wands" to 3D scanners used for industrial design, reverse engineering, test
and measurement, orthotics, gaming and other applications. Mechanically driven
scanners that move the document are typically used for large-format documents,
where a flatbed design would be impractical.
More from Wikipedia (http://en.wikipedia.org/wiki/Image_scanner)
More from Wikipedia (http://en.wikipedia.org/wiki/Image_scanner)
More of input devices at http://en.wikipedia.org/wiki/Input_device
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