Scanner Input Device And Saveral Kinds Of Scanner

Another input device that is being used increasingly is the scanner. Often, there are situations when some information (picture or text) is a available on paper and is needed on the computer disk for further editing. The simplest way to do this would be to take photograph of the image directly from the source, and convert it into a form that can be saved on the disk and then edited.

A scanner scans an image and transforms the image to ASCII codes that is used by the computer to represent the characters you find on you keyboard, such as, alphabets, numbers, punctuation marks and graphics. These can be edited, manipulated and printed.

There are three types of scanners:

Flatbed Scanner: The Flatbed scanner is most common desktop scanner. It resembles the copy machine. In a Flatbed scanner, The item being scanned rests on a glass plate whicle the scanning head moves underneath it. It works like a copy machine except that it creates a file of the document rather than a paper copy.
Sheetfed Scanner: Personal sheetfed scanners have gained popylarity during the last few years. These devices are more like fax machines, because they move the page being scanned past the scanning head. The main difference between this type and a flatbed scanner is that the image sensor does not move but the document itself is pulled past the mounted image sensor.
Handheld Scanner: The handheld scanner is a scanning device where the scanning element is built inro a small handheld unit. The handheld unit is then waved or rolled over the item being scanned.

Many of the scanners available now-a-days are capable of not only scanning text and graphics, but also integrating text and graphics files.

Scanners are used to reproduce photographs on the computer screen. They can be used in training programs using computes and in desktop publishing. Businessses use scanners for storing documents on the computer.

Comouter Input Devices Mouse

myLot User ProfileThe mouse was invented by Douglas Engelbart of Stanford Research Center in 1963, and pioneered by Xerox in the 1970s.

The mouse is an input device that is important for graphical user interfaces because you can simply point to option and click a mouse button. These types of applications are often called point-and-click programs. The mouse is also important for graphic programs that allow you to draw pictures by using the mouse.

A mouse may have one, two or three buttons. The function of each button is determined by the program that uses the mouse. A software package may use one, two or all there of them. In its simplest form, a mouse has one button. Moving the mouse on a flat surfaces a corresponding movement of a pointer on the screen. Placing the pointer on an option and clicking the button results in selecting that Option.

A mouse may be classified as a mechanical mouse or an optical mouse, on the basis of the technology it uses. In a mechanical mouse, the ball that projects through the bottom surface rotates as the mouse is moved along a flat surface. The direction of rotation is detected and relayed to the computer by the switches inside the mouse. Microsoft, IBM and Logitech are some well-known makers of mechanical mouse.

An Optical mouse uses a light beam instead of a rotating ball to detect movement across a specially patterned mouse pad. MSC Corporation makes the optical mouse that uses LEDs and photo-detectors to trap movement.
Following are some categories of mouse:

Trackball Mouse :- In a Trackball mouse, the ball is rolled at one place with the thumb, fingers and palms rather than rolling the mouse on the table top.

Joystick Mouse : A Joystick usually includes two upright sticks that are moved with the hand a button is pressed on either stick. Joystick mouse is basically used by children, recreational users and other who prefer the joystick to the mouse or trackball.


Light Pen Mouse : A light pen utilizes a light-sensitive detector. It requires you to hold a pen and point it at the screen.

Wireless Mouse : The wireless mouse is a mouse without a cable. This mouse works upto one and a half metres away from the computer.
Touch Pad Mouse : A touch pad is a small, flat, rectangular pointing device that is sensitive to pressure and motion. These devices are mostly used on portable computers.