Mr. Abdul Wajid

The data or instructions you type into the computer are called input

Input devices used to get data into a system.

Get data into a system as accurately, least amount of time.

It’s a cheap device.

Keyboard Mouse Tracker ball Touch sensitive pad Joystick Light pen Touch screen Graphics tablets Magnetic Strip Reader Bar Code reader Digital cameras Web Cameras

OCR MICR OMR Punched Card Kimball tag Voice recognition Microphone EPOS EFTPOS Video digitiser Scanner Touch Phone Telephone

Keyboard is the oldest and most familiar of all input devices

Keyboard are intelligent devices and contain their own chips.

The microprocessor scans the keyboard hundreds of second to see if a key has been pressed .

The CPU translate that key and convert into ASCII code.

A standard keyboard called QWERTY keyboard.

New keyboards, called concept keyboards, have been developed for ergonomics

The goal of this keyboard is to provide comfort and safety.

The user who spends a lot of time in typing may experience repetitive injuries of wrist and hand.

Higher typing speeds can be achieved.

That requires no wires It is also called wireless keyboards. It transmits data using wireless

technology like radio waves or light waves

These keyboards make it easy for blind users to input data into a computer

There are also keyboards with large coloured keys that are easier to see.

Each key is about one inch square.

Most computers come with a keyboard supplied

People are used to using keyboards to enter data, they need very little training

A skilled typist can enter data very quickly

Specialist keyboards are available e.g. ergonomic, gaming keyboards

It is easy to make mistakes when typing in data

If you can't touch type, it can be time consuming to enter data

Keyboards are not suitable for creating diagrams

Disabled people often find keyboards difficult to use

Excessive use can lead to R.S.I.

That translate its movement on the desktop into digital information.

Moving the mouse produces movement of cursor or the pointer on the screen.

The mouse is also provided with buttons to press.

Movement of ball bearing is used to produce electrical signal.

Small lights under the mouse are reflected on the photoelectric cells.

To select options from a menu or form a set of icons

To position the cursor when editing text or using a design package.

To draw shapes. It selects a position on the screen

more quickly than is possible with a keyboard.

Is similar to tracker ball. Is a device which enables the user to

control movement on the screen by a small lever.

The lever can be moved in any direction. Some joysticks give more control on the

screen.Uses Controlling objects in computer games Producing graphics Scanners in hospitals

Is a pen shaped device, held in the hand which can detect the presence or absence of light

It is connected by the cable to a recording device or to a computer or computer terminal.

Electrical signals are sent along the cable indicating whether or not light of sufficient intensity is being sensed.

To detect bar codes To indicate a point on the screen It removes the need to type or write. It is faster than typing.Disadvantage:It can only record the presence or

absence of light.It only works with software written for

it.

Is also known as digitizing or digitizing pad.

The digitize data means to convert it from analog form to digital.

A design is put on the board and its shape is traced out with the stylus.

Electrical signals sent to the computer record the position of the stylus.

Encoding the picture into binary form

It can be used to digitize drawings with great accuracy.

Reproducing drawings and designs Producing layouts of printed circuit

boards. Digitizer Maps.

Is a small, flat surface over which the user moves his finger.

The movement of the finger moves the cursor on the screen.

A touch pad also has one or more buttons near it .

These buttons like mouse buttons. Touch pads are commonly used with

notebook computers

Is a video display screen that receives input from the touch of finger

Examples ATM Petrol Pumps

Is a short length of magnetic tape stuck on the surface of a tag, card or document.

On plastic tags or cards the strip is sealed in.

Tags with stripes identify the item they are attached to.

Examples: On credit card On bank cards A phone Card Cash issue Terminals

It is simple to produce. It is not easily damaged. It stores a large no of characters.Disadvantages The data can be changed or erased

by magnetic field.

Is set of parallel printed lines of differing thickness, which represent a number.

The number represented by the bars is also printed above or below the bar code.

When bar code are used on shop goods, the number coded identifies the product and have following information

1. Country of region 2. Manufacturer 3. An item number for the product.Examples: Used in Barcodes Library System Warehouse stock

Printed easily The type of item or its price does not

have to be repeatedly written down or typed.

Disadvantages: bar codes cannot be changed and

thus there are unsuitable prices. Bar codes only be read by machine. Only numbers can be coded in this

way.

Is a technology that reads typewritten , computer printed or handwritten documents.

It translate the image into a form that can be recognized by computer.

OCR devices read printed characters using OCR font.

An OCR device determines the shapes of characters by detecting patterns of light and dark.

In department stores To scan financial documents such as

company

It is also called mark sensing device. It uses light to scan input data to convert it

into electrical/digital signal. The signals are then sent to the computer

for further processing. Examples Voting ballot Multiple choice answer sheet marking Enrollment forms

In OMR there is typing involve so errors and takes time is less

Reduces the cost of inputting large amount of data

The method is useful when results of the test are needed very quickly

Disadvantages Readers are very expansive Only certain fonts are acceptable. There is high rejection rate

Characters are printed using an ink containing iron oxide.

As the document passes into the reader the ink is magnetized, so that the character shapes can then be recognized electrically.

It is used by banks industry for check processing.

Each check contains MICR characters at the lower left edge.

These characters represent check number ,bank number and account number

Branch codeCheque number

Account number

Documents can still be read when folded, written on

Disadvantages Readers are very expansive Only certain fonts are acceptable.

Contains holes in different positions which mean something when they are read by a reader.

Punched cards were the main method of entering data into computers.

Example: The clock card which is used to record the

hours a person works so that wages can be calculated.

Kimball tags are the small cards with holes punched in them that you see attached to clothing in certain shops.

When you buy the goods, one of the tags is removed and sent for processing to a computer centre.

Stock is reordered without any writing or typing the data.

Disadvantages: They are small and are easily mislaid.

Using a microphone human speech is coded into a sequence of electrical signals.

The computer searches a set of stored patterns for the sound which has been input

It is now popular for inputting data into word processing or database packages.

Useful for handicapped people with limited movement

No typing or data preparation is necessary.

Disadvantage: Few words can be recognized and the

error rate is high. Not suitable in noisy places.

Is used for input device for a speech recognition system.

The voice pattern of user is then converted into instructions to the operating system or application software or text.

Uses as voice mail messages

Are the cash registers which act as the terminals to a main computer system

Providing customers with item used in bills.

Give useful management information

Similar to EPOS terminal but some additional features.

They are able to transfer funds from your bank account directly to a store’s switch card called a debit card.

Example: Switch card

You can use it instead of a cheque. Faster method of payment Money is instantly transferred into its

account. You can also get cash back using your

debit card.Disadvantage: They may be stolen and they are said to

encourage people to spend more money.

Is the combination of hardware and Software that converts an analogue video signal into a digital signal in computer’s memory

Is used to convert a frame from a video sequence into a picture

Each frame from the video is converted using video digitiser.

It may be played back in any required sequence.

Is also called image grabbing or frame grabbing

Take up a lot of main memory and when stored use a large amount of disk space

Digitiser pictures Can be printed in a magazine or document

To make television adverts and to produce pop videos.

Read data or information from the source

Source could be written document, a price tag, a graphics image , or photograph

To scan text or images which manipulated in some way before being printed

Optical Scanner Optical Reader

It is a light sending input device. The scanner image depend upon resolution Image will be sharper if the scanner

provides high resolution it provide OCR Software Different types of Optical Scanner are Flatbed Scanner Sheetfed Scanner Handheld Scanner

Is used to store, picture in digital form. Store images using different ways like

floppy disk, memory stick, mini CD ,PC Card and micro device.

Can be connected to a computer easily through USB port.

Image resolution for digital camera measured by megapixels.

Higher resolution photo takes up more memory .

No film is needed No expensive developing costs Pictures are in digital form so it can

easily sent over the internet You can adjust the size of image

Is simply a digital camera that is used to capture still images and video images

These images can then be transmitted to a computer where they are stored in graphics format

Pictures can be used on the websites

Camera placed on top the screen such a system allow video conferencing

Advertising Checking on children in nurseries Checking on the weather on the other

part of the world

Having a different tone of each number when pressed key

Using these different tones that the numbers dialed are recognized and routed to correct telephone

Can be used as a data entry device Home banking system use touch tone

telephone

Output device provide results in a suitable form after data processing.

Output devices are used to get data out of a system.

They should be able to do this as accurately and quickly as possible, and with the minimum of human intervention.

• Visual devices (including Visual Display Units [VDUs], screens, and monitors)

• Hard copy devices (including ink jet printer, laser printers, dot-matrix printers, and plotters)

• Sound devices• Computer controlled devices (including

robots)

Most common output deice It is known as display screen The output display by monitor is

called soft copy so it is ideal for showing the results from an enquire where no printed is needed.

Size Color Resolution Video Display Adapter

CRT Flat Panel Monitors Touch screen Monitors

Creates the image on the screen through electronic beam

This is same type that is use in Television

It consists of one or more guns These guns generate red ,green and

blue (RGB) colors.

LCD screens are most often seen on portable or laptop computers

These are used in these applications because they are small and light.

Also used where space is at the premium.

The molecules this substances line up in such a way that the light behind the screens and creates an image.

Use in banks and Multinational companies

Larger than VDU and have greater resolutions

lines on the screen don’t look as through they are made up of lots of tiny dots.

Are often used in conjunction with light pens

It prints character ,symbols and graphics on paper.

Print resolution is commonly measured in dots per inch (dpi)

Different types of printer are Impact Printer Non Impact Printer

Its act like a typewriter It prints characters or images by

striking a print hammer or wheel against an inked ribbon

Dot matrix printer Line printer Daisy wheel Printer

It produces printed images when tiny pins on a print head strike an inked ribbon

When ribbon pressed against the paper, it creates dots that they form characters and graphics

Which can transfer print through layers of paper.

Able to print multi-part sheet where It generates lot of noise ,its print quality is

not good

Is a fast impact printer It prints a entire line at a time Its speed is measured in line per

minute

Similar to typewriter Uses print wheel A motor rotates the wheel. Its slower than Dot matrix but better

in quality

Prints characters and graphics on a piece of paper without striking the paper.

These printers are faster than impact printers

Inkjet printer Laser printer Thermal printer

It prints characters and graphics by spraying tiny drops of liquid ink on paper

The print head of an inkjet printer consists of nozzles

It has two cartridges black and white These printers can produce quality text

and graphics in both black and white color slower than laser printer but faster than

dot matrix printer They can print 1 to 6 pages per minute Cheaper in price Satisfactory in color

Creates image on the paper by the laser beam

Also called page printer because they print complete page at a time

It contain toner Throws magnetic powder on paper in

the form of microscopic dots

Print a page at a time so it is fast and it print pages 10ppm

They produce high quality of text and graphics

They are quiet in operation compared with dot matrix

Equipped with paper trays for both the input and the output papers

Are more expensive than dot matrix or ink-jet printer

They are quite large and can take up lot of disk space

Quite complex so the repair bills can be high

Multi part stationary cannot be used

Is a printer that uses heat process to transfer colored dyes or inks to the paper

Is the best color printers currently available but it is very expensive

Is an output device that is used to produce image quality graphics in variety of colors

Used to create maps, architecture drawings, graphs and charts

A plotter works by drawing lines on paper using pens held in a mechanical arm

It may be in form of Flatbed Plotter Drum plotter

Is an output device that is used to produce image quality graphics in variety of colors

Used to create maps, architecture drawings, graphs and charts

A plotter works by drawing lines on paper using pens held in a mechanical arm

It may be in form of Flatbed Plotter Drum plotter

Used to plot or draw images. It contains pens for drawing images. The paper is placed on table like

surface Software instructs the pens to move

down on the paper

Uses a rotating drum or cylinder

The drawing pens are mounted on the drum

The pens move to the left and right as the drum rotates

Advantage of drum plotter is that the length of the plot is almost unlimited

Visually people find the spoken word from the computer

Special software is used for this process

In a word processor each letter is typed and it can hear with headphone.

An audio device translate audio information from the computer into sounds that people can understand

Speakers Headsets

Sometimes the output from one computer system can simply be a series of electrical signal

In this case one computer is being used as a terminal and work that is done sent as electrical signals

Electrical signals can be output and used to control all kinds of devices such as

Heating system Alarms Robots Actuators Computer aided manufacturing (CAM) Computerised numerical control (CNC)

A typical computer controlled device used in computer-aided manufacturing – a robotic arm