Input & Output Devices (Edexcel IGCSE ICT)

Keyboard

Entering data into a computer

• Easy method of entering data

• Very common

• Repetitive strain injury

• Slow to enter data compared to direct data entry

Mouse

To select on screen objects

• Intuitive and precise control

• Fast to make on-screen choices

• RSI (strain on wrist)

• Requires flat surface

• People with disabilities can find them difficult to use

Joystick

Moves sprites/characters around a game

• Enhances gameplay/simulation experience

• Improve realism

• Accurate

• Expensive

• Limited use outside of gaming and simulators

Graphics tablet

Use a stylus to draw or write

• Precise

• Natural feel

• Ergonomic

• Cost

• Learning curve

• Battery life

Scanner

Convert paper documents to electronic

• Accurate reproduction

• Easy to share and store

• Combined with barcodes becomes a DDE

• Quality depends on resolution

• High quality means can be slow

Digital camera

Taking photos/videos

• Vast amounts can be captured

• No developing

• Easy to share

• Storage compression can lead to a loss in quality

• Need to be tech-savvy to use effectively

Webcam

Streaming images/video

• Real-time communication

• Cheap

• Multipurpose

• Image quality

• Privacy concerns

Microphone

Input speech, sensor to pick up sounds

• Hands-free input

• Can be used for voice recognition

• Fast

• Variable quality

• Verbal inputs can be inaccurate

• Need to remember key words and/or phrases

Resistive touchscreen

Pressure causes layers to 'touch'

Durable

• Intuitive

• No need for a separate pointing device

• Easy to keep clean

• Screens can get dirty

• Easily scratched

• Less precise than a mouse

Capacitive touchscreen

Conduct electricity

Finger causes a change in electrical charge and can be measured precisely

OMR

Optical Mark Recognition

Read marks on exam paper in pen/pencil

• Fast processing

• Reduced human error

• Limited to specific forms

• Cannot read handwriting

• Form must be completed accurately

OCR

Optical Character Recognition

Text to digital data

• Fast data entry

• Accurate and less error prone

• Can struggle with complex layouts

• Font dependent

• Not always 100% accurate

• Expensive

Barcode scanner

Reads barcode labels

• Fast and accurate

• Low cost

• Allows for automatic stock control

• Tried & trusted

• Requires line-of-sight

• Barcodes are easily damaged

• Barcodes can be swapped/altered by consumers

Biometric scanner

Fingerprint/facial/voice/iris recognition

• Easier than passwords

• More secure

• Speed

• Privacy concerns

• Expensive

Magnetic stripe reader

Debit/credit cards

• Fast

• Simple to use

• Secure (unreadable)

• Magnetic stripes can get damaged and become unreadable

• Reader must be in close contact

Chip and PIN reader

Retail card payments

• Secure

• Reduced fraud risk

• Requires PIN input

• Potential for skimming

• High payment limits an issue for stolen cards

RFID reader

Contactless payments

• Fast transaction (no pin)

• Data wirelessly transferred securely

• Retailers don't have to access customer credit/debit information

• Transaction limit is smaller

• RFID signals can be read/intercepted

Analogue sensors

Measure environmental data e.g. temperature, light, sound, humidity etc.

• Generally accurate

• Provides real-time information

• Automatic

• Can collect data from places where they may be threat to human life

• May require calibration

• Data must be converted to digital data (ADC)

• Data may need to be checked for accuracy

CRT monitor

Display output from a computer

Screen size is measured diagonally in inches

Resolution is the number of pixels measured horizontally across the screen

• Large viewing angles

• Can be used with light pens

• Run hot

• Heavy

• Consume more power (than other monitor types)

LCD monitor

• Low power

• Lightweight

• No flickering

• No image burn-in

• Motion blur/ghosting

• Colour & contrast variable from different viewing angles

LED monitor

• No motion blur/ghosting

• Low power

• Long life

• More expensive (than LCD)

• Contrast can be poor

Laser printer

High volume printing

Electronically charged toner

Dry ink

• Fast

• High-quality prints

• Lower cost per page

• Expensive initial cost

• Limited to flat surfaces

Inkjet printer

Home printing & photographs

Uses wet ink separated into black, cyan, magenta & yellow

Tiny dots sprayed onto paper

• Lower initial cost

• High-quality prints

• Ink can be refilled

• Slower

• Higher cost per page

• Ink may smudge

Dot matrix printer

Useful when printing multiple copies

Paper is impacted through a ribbon of ink

• Low cost

• Can print multi-part forms

• Very good for long print runs

• Noisy

• Low print quality

• Slow

3D printer

Create real-life versions of digital models

• Customisable designs

• Rapid prototyping

• Medical benefits

• Limited materials

• Slow process

• Counterfeit items easier to produce

• Very expensive

Plotters

Create drawings & blueprints

• High accuracy

• Can print on various materials

• Inexpensive to run

• Slow

• Expensive to buy

• Large size

Multimedia projector

Output computer usually to much larger display

• Large display

• Good for presentations

• Space saving

• Requires darkened room

• Expensive bulbs

• Need separate audio

• Quality is variable

Speakers

Output audio

• Range of sizes and power outputs

• Immersive audio

• Helps people with disabilities

• Expensive for higher quality output

• Varying sound quality

Actuators

Control motors, pumps, switches etc.

• Precise movement

• Programmable

• Allow automatic control of many devices

• Requires power

• Potential mechanical wear

• Requires DAC interface