Input Devices - Year 10

GCSE Information Technology


Input Devices

Manual input devices – data entered by hand

Direct input devices – these handle large amounts of data

These are used to put data or instructions into the computer


Keyboard

QWERTY - the first row of letters. Other types of keyboard – supermarket tills Ergonomic keyboards – split board


Advantages/Disadvantages

Keyboard used by

Good for manual text entry.

Special keys for special functions

Hot key combinations to simplify tasks

Familiar device

Mistakes easily made

Large footprint (desktop space)

Slow data entry for most

No real use for drawing

RSI

Widespread use at home and in the workplace


Pointing devices

Pointing device. Next most common type of input device Developed with GUI Touch pads and trackballs on portable

computers. Upside down mice


Mouse and pointing devices used by


Enable drawings and pictures to be done Pointing device used in Portable computers

Allows different data to be put at any point directly on the screen

Good for selecting items from menus

Small

Difficult coordination at first

Need a flat space

Dust interferes with use


Joystick

Used to control movement from side-to-side, up-and-down and diagonally.

One button on it to make something happen - a character in a game jumping or firing a gun.

Analogue and Digital types of Joystick


Joystick used by


Computer games Flight simulation VR and robot control

Better simulation Specialised use

Limited use


Touch screen & How it Works

Two types: Criss-crossed with infra-red beams Touching the screen at set points interrupts the

beam and sends a message to the processor Pressure sensor models Pressure sensors identify where pressed


Touch screen used by


fast food chains and restaurants - easy to keep clean and re-program if changes need to be made to the menu.

Used in public places like shopping malls - most direct data entry

No training or practice needed – instinctive use

Need specialist coated screens

limited but specialised use


Digital camera

• Storage - can store more pictures than an ordinary camera – memory stick.

• Different resolutions• software to manipulate the image or to put the pictures

into albums and give slide shows.• Video input


• converts light passing through the lens – It gives a value to each particle of light

• Pictures are stored inside its memory • transferred to a computer by

connecting the camera to it.

How a digital camera works


Digital camera used by


widespread use to send photos electronically – web albums, attachments

Used in screen presentations

No need to scan pictures to get them into computer

No developing time or costs Images can easily be edited

expensive – up to £1000 Different expertise to learn Need specialist paper to get

good print Take up a lot of computer

space


Scanner

used to input pictures and text into a computer. two main types of scanner; hand- heldflat-bed. Most common

A4 size but can get A3 image software to let you manipulate the images –

crop, rotate, add special effects etc


A laser beam passes over the surface and detects the light intensity of every spot on the paper.

It gives a value (digital) to every spot.value is transferred to the screen where

the image is recreated.Resolution depends on dpiother accessories - facility to copy

slides.

How a scanner works


Scanner used by


offices to incorporate images into promotional literature. Growing use in home in schools for teachers to produce illustrated worksheets

saved hand drawing images to illustrate typed text

Scanned images are more appropriate than clipart.

Difficult to learn how to use. Some image formats can take

up a lot of space Can be difficult to connect takes up desktop space


Special software associated with a scanner converts a digital image of scanned text into real text so it can be edited on the screen.

The text is scanned in as a bitmapped image and software compares each character with a database of characters

OCR & How it Works


Widely used in offices to save a lot of copy typing Passports and ID cards

OCR is used by

Advantages and disadvantages

Saves a lot of time on typing

need to check to see if you need to correct everything

Difficult to interpret pages with complex layout; need more expensive OCR software.


Concept keyboard a flat board with a grid of programmable keys on its

surface. Software allows you to change the instructions for each key.

A single key or a group of keys can be set up to carry out a task.

Paper overlays are placed on top of the keyboard with pictures drawn on them to represent what will happen if the keys are pressed.


Concept keyboard used by


used with young children in primary schools who can’t use an ordinary keyboard

Restaurants

simpler than a normal keyboard = fewer things to click on and less likely to make a mistake.

Can program them with pictures as well as words

Need reprogramming a lot New overlays to be

designed or bought


Graphics Tablet

When the special pen touches the surface of the graphics tablet, data about its position is sent to the computer. Produces an exact copy of what is being drawn

a flat surface and a pen, or stylus, used to produce freehand drawings or trace around shapes.

How a Graphics Tablet works


Graphics tablet used by


Architects and people who do detailed design

Computer artists who feel more comfortable inputting into a flat surface than to a screen

more precise input for drawings

More natural to people who paint or draw using a pen/pencil

Takes up room on the desk

Can’t be used for text


Microphone

used to input sound into a computer system.

used for voice recognition systems - convert sounds made by a user into commands that the computer can carry out.

As computers become more powerful in the future, voice recognition will be a much more common input method for all computer users.


Microphone used by


Far faster and more direct.

Any sound can be stored

Growing use in offices as software improves. Handicapped people Internet and telephony

Need voice recognition software. ‘training’ to recognise your voice.

speech is full of inconsistencies and false starts etc need for much editing after entry.

Background noise

Sometimes our voice is affected by things like colds.


Connected to the computer Electronic beam, controlled by the

computer – this builds up the image on the screen

Light Pen

How a light pen works Connected to the computer by cable. As the pen touches the screen at different points, signals are sent to the computer by an electron beam and a picture is built up.


Light pen used by


popular with Tablet PCs Surgeons

More natural feel

Good for inputting drawings

Response time can be slow

Depends on handwriting recognition for text


Video Camera

Like ordinary video cameras except images stored digitallyCaptures still and moving imagesImages can be stored and edited on a computerImages stored on memory stick or mini DVD

UsesHome and commercial


Web Cam

A video camera connected to a computer A live cam continually provides new images that are transmitted

(streaming video) several thousand sites with cams Captures still and moving images Allows video conferencing in business Home use systems

Uses Coffee machines Advertising – Travel promotion -cruise ships use them to show potential

customers what is going on and where ship is Childcare centres – so parents can keep a watch on children Weather checks – check anywhere in world to see what weather is like Traffic information Visualisation of on-going events


MIDI

Data is input through a piano-type keyboard or by sensors that respond when struck.

A variety of sounds generated from one keyboard. 'real' sounds recorded into the system through a

microphone and then sequenced to produce musical effects.

The music industry uses MIDI systems Schools.

Uses


Remote Control

These use infra-red signals to give instructions to devices they control

TV, DVD and video Computer input devices

Uses


Direct Input devices involve the use of machines to speed data input

Optical Mark Recognition (OMR) Magnetic Ink Character Recognition (MICR) Bar Codes Magnetic Stripe Readers Sensors and Data Logging Others

Direct input devices


Uses special sheets and a machine - a Reader Detects marks made in special places on the paper How it works – light from pencil mark is different

level from rest of paper

Optical Mark Recognition

expensive, need special machine and paper

Uses With Data Capture Forms to

enter results of questionnaires and surveys

lottery, MC exams, food ordering

very fast 1/100th of a second to mark an exam



Needs a special machine – Reader + the use of special magnetic ink.

How it works – Uses a special font - only 14 characters (0-9 + 4 special characters). The characters are passed through a magnetic field

Magnetic Ink Character Recognition

(MICR)

Advantages/ Disadvantages

speed (cheques cleared very quickly): reliable (will read even if cheque is crumpled)

expensive and specialised font

Uses

numbers at bottom of cheques


A set of lines of different thicknesses that represent a number..

How it works – Light shone on the lines and t reflected back is detected and generates a code to the computer; this gives information about the product – price, size, manufacturer.

Can be a read with a light pen or a laser beam

Bar Codes

UsesSupermarkets, libraries

Advantages/ Disadvantages speed (60 per minute), can give detailed

information (supermarket till receipts); can design your own

– specialised use and need time to set up the codes


A magnetic strip like a tape which contains coded information. This is read by a machine

How it works – a code is read and interpreted

Magnetic Stripe

Readers

don’t have to carry money around Development of Smart cards

EFT (Electronic Funds Transfer) using a debit or credit card, ATM

–cards – a chip can hold more information

– security – need a PIN number (fraud); only limited amount of information)

Uses Advantages/ Disadvantages


A way of collecting data over a long period of time without people. data transferred using communication links to a computer and interpreted. (Period of logging and time interval are important)

How it works - Uses different sensors to measure things like temperature, light, pressure, movement. May need converter to convert from analogue to digital

Sensors and Data Logging

accurate readings, data can be logged over a long period of

time, can be placed in areas where it is difficult

for humans (dangerous, inaccessible, monotonous).

burglar alarms, weather forecasting, scientific experiments, hospitals, traffic movement.

Uses Advantages/ Disadvantages


Video Digitiser

Moving pictures captured by a computer using a video digitiser .

by the TV industry to edit TV programmes. Video clips for multimedia CDs digital video cameras in shops, editing of videos through

computers will become commonplace.

Uses

Input Devices - Year 10

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