Hardware and input devices

Hardware

Types of computers

Input devices

SMILE

Introduction Hardware??? Computers are categorised by their size

and power! We are going to focus on hand-held

computers Nowdays most procesing is done on

mainframe computers and supercomputers

Some calculations like weather forcast would take enormous time if processed on a your computer.

Airlines and large hotels need also very capable computers alse they would not be able to do simple search due to their large database size!!!!!!!!!

For these and many other reasons we do need powerfuil computers

Microcomputers & microprocessors

Computers we use are called microcomputers

However all computers consist out of following parts: Input devices Output devices Processor Storage device

Homework!!!!!!!

Try to find examples (& pictures) of big size computers!!!!!!!!!!!!!!

Cont..... Processor consist out of number of

different parts all of these parts fit on one small chip microprocessor

All on one chip integrated chips. Microprocessors are dedicated devices Why? You can’t take microprocessor out of you

microwave and put it into your washing mashine.

Input devices No use of computers if you cannot tell it to do

something! We need input devices data & commands When thinking of input devices what is needs

to input to the computer!!!! An input device lets you communicate with a

computer.  You can use input devices to enter information and issue commands.  A keyboard, mouse, scanner, digital camera, touch pads and joystick are examples of input devices.

Keyboards Invented 100 years agoUsed to type data into the

computer Most common input device today Has special keys for giving the computer commands

Commands tell the computer to do something, like save the file

These special keys are called command or function keys

There is no specific standard but we have stuck to the qwerty keyboard

Different types of keyboards It depends what we need to input ATM keyboard, piano keyboard, alarm system keboard

etc.

Pointing devices Touch-sensitive screens are nice thing

but not in all situations! When we have to select something that

is to small for our finger it is better to use pointing devices

Mouse one of the pointing devices Laptops have tracker balls or a touch

pad Joystick allows to give direction

used for game playing and more serious once aircraft navigation

Mouse - most common pointing device 

Track ball - basically an upside down mouse 

Joystick

Game controller 

Video digitiser and scanners

Everything around us is in analog form So we need to store and analoge picture

in a computer We need analoge to digitale converter

(A/D converter) Video digitiser is a device like scanner that

converts anal. picture into digit. picture Picture is split into number of pixels

same in digital cameras

Scanners A scanner allows you to scan documents,

pictures, or graphics and view them on the computer.  You can also use software to edit the items you scan.

Used to put printed pictures and text into a computer

Converts an image into dots that the computer can understand

To scan text, optical character recognition (OCR) software is needed

Remote control

Uses usually infrared beamEvery time to press a button it will

send some coded data

Digital cameras Used to take electronic

pictures of an object The pictures taken by a

digital camera can be used directly by a computer

Video Capture Card

Usually place inside the computer's case Use to put video into a computer Need a video source, either a video

camera or video recorder

Magnetic input devices These are not storage devices Magnetic input devices come in two

forms: Magnetic stripes put usually on a back

of credit and bank cards contain information about the card holder it is read by magnetic stripe reader

Magnetic ink specilized ink very easy for machine to read it by magnetic ink character recognition MICR account numbers on cheques.

Optical mark readers

OMRs devices used to read marks made in pencil or other forms of documents

It is sometimes very practical and usefull Multiple choice questions or survey

results, signitures or whole documents.

Graphics tablets

It is used with stylus to input freehand work into a computer

It is practical for those disabled who cannot use keyboard or mouse

What ever you draw or write is going to be transfered to the computer

Light pen It is used as a pointing device User points at the screen and the

computer uses information about timing and light intensity to highlight the position on the screen

It is very much usefull for filling in onscreen data-capture forms

Microphones

It is used to input sound to a computer Sounds are analog data so they have to

be converted into digital form Microphones can be used for voice

recognition applications as well as for voice commands

MIDI Most of the musical instruments are

electronic and a computer is electronic Still musical instruments cannot directly

communicate with computers We need device called MIDI musical

instrument digital interface

Sensors Devices that input data automatically

from the physical world There are two sort of sensors:

Ones that sensor things that human being can detect (temperature & light)

Ones that sensor things that human beings cannot detect (magnetism, microwave beam)

The main sensor types are:

TEMPERATURESOUNDMAGNETISMRADARLIGHTPRESSURETOUCHMICROWAVE

PROXIMITY SENSORS

PROXIMITY SENSORS

PROXIMITY SENSORS

Proximity sensors measure how close something is to sensor.