IGCSE – ICT Chapter 2 – Input and Output Devices Study Notes

INPUT DEVICES AND THEIR USES

Keyboards

  • Description: Keyboards are the most common data entry devices.

  • Connected via: USB or wireless connection.

  • Functionality: When a key is pressed, it is converted into a digital signal for the computer.

  • Health Issues: Repetitive strain injury (RSI) can occur with frequent use.

  • Solution: Ergonomic keyboards provide alternative key arrangements and wrist support.

Uses of Keyboards

  • Inputting data in applications (text in word processors, numbers in spreadsheets, etc.).

  • Typing commands (e.g., Prnt Scrn, Ctrl+P for printing).

Advantages of Keyboards

  • Fast data entry.

  • Familiar to most users.

  • Verification checks can be easily conducted.

Disadvantages of Keyboards

  • Challenging for users with limited arm/wrist mobility.

  • Larger desk space is required compared to other devices.

Numeric Keypads

  • Description: Input device primarily for numbers, some models allow alphabetic input via a function key.

Uses of Numeric Keypads

  • ATMs for PIN and transaction amounts.

  • Mobile phones for phone numbers.

  • POS terminals for manual entry if barcode readers fail.

  • Chip and PIN devices for transactions.

Advantages of Numeric Keypads

  • Quicker entry of numeric data compared to keyboards.

  • Compact and portable.

Disadvantages of Numeric Keypads

  • Small keys can hinder usability.

  • Number order may not feel intuitive to all users.

Mouse

  • Description: A pointing device that controls the on-screen pointer position.

  • Types: Optical and wireless mice are common in modern use.

  • Functionality: Features typically include two buttons and a scroll wheel.

Uses of the Mouse

  • Software navigation (open, close, minimize applications).

  • File management (move, group, delete items).

  • Image editing and menu navigation.

Advantages of a Mouse

  • Faster selection compared to keyboards.

  • Quick navigation through software and the web.

  • Requires less desk space than a keyboard.

Disadvantages of a Mouse

  • Difficult for those with limited hand/wrist movement.

  • Prone to dust accumulation if not care for.

  • Usability is hindered without a flat surface.

Touchpad

  • Description: Integrated pointing device used in laptops.

  • Functionality: Controlled by finger movements and taps.

Uses of Touchpads

  • Similar functions to a mouse.

Advantages of Touchpads

  • Integrated with the laptop, enhancing portability.

  • Fast navigation and option selection.

Disadvantages of Touchpads

  • Difficult for those with limited hand/wrist mobility.

  • Pointer control can be harder than with a mouse.

Trackerball

  • Description: A pointing device where the user rotates a ball to control the screen pointer.

Uses of a Trackerball

  • Alternative for users with RSI.

  • Industrial control rooms for efficient navigation.

  • Luxury cars for function selection.

Advantages of a Trackerball

  • Requires less fine motor control than a mouse.

  • More robust and space-efficient.

Disadvantages of a Trackerball

  • Typically not included as standard; may require separate purchase.

  • User training may be necessary.

Remote Control

  • Description: Operates devices using infrared signals.

Uses of Remote Controls

  • Televisions, multimedia systems, and industrial machinery control.

Advantages of Remote Controls

  • Operable from a distance.

  • Useful in hazardous environments.

Disadvantages of Remote Controls

  • Difficult for users with reduced mobility.

  • Signals can be blocked by thick walls.

Joystick

  • Description: Input device with a stick for controlling pointer positions.

Uses of Joysticks

  • Primarily in video/computer games and simulators.

Advantages of Joysticks

  • More intuitive navigation for gaming applications.

Disadvantages of Joysticks

  • Less precise than mouse control.

Driving Wheel

  • Description: Input device mimicking a vehicle's steering wheel.

Uses of Driving Wheels

  • Video games (car racing) and vehicle simulators.

Advantages of Driving Wheels

  • Provides natural steering experience.

  • Supports a realistic gaming environment.

Disadvantages of Driving Wheels

  • Typically expensive compared to other input devices.

  • Sensitivity can be unrealistic.

Touch Screens

  • Description: Allows user selection of options through direct screen interaction.

Uses of Touch Screens

  • Self-service tills, ATMs, public information systems, etc.

Advantages of Touch Screens

  • Quick option selection.

  • User-friendly interface.

Disadvantages of Touch Screens

  • Limited input options.

  • Prone to dirt and user fatigue.

Scanners

  • Description: Input device for digitalizing hard copies (text and photographs).

Uses of Scanners

  • Document archiving and converting formats.

Advantages of Scanners

  • Provides faster input via OCR.

  • Enables quality recovery of damaged originals.

Disadvantages of Scanners

  • Resolution can be limited by scanner quality.

Digital Cameras

  • Description: Capture images using electronic sensors instead of film.

Uses of Digital Cameras

  • Photography, data capture in various fields (e.g., dentistry).

Advantages of Digital Cameras

  • Immediate image transfer to computers.

  • Environmentally friendly as they don’t require film.

Disadvantages of Digital Cameras

  • Requires some computer literacy for handling images.

Microphones

  • Description: Converts sound waves into electric signals.

Uses of Microphones

  • Speech input, music sampling, voice recognition, intruder alarms, video conferencing.

Advantages of Microphones

  • Faster to input speech formatted data.

  • Facilitates real-time sound manipulation.

Disadvantages of Microphones

  • Can require significant memory for sound files.

Sensors

  • Description: Devices that measure physical quantities like temperature, light.

Advantages of Sensors

  • Continuous and accurate readings.

  • Can automate systems requiring immediate response.

Disadvantages of Sensors

  • Susceptible to spurious results from faulty devices.

Light Pens

  • Description: Used for input on CRT screens through light detection.

Advantages of Light Pens

  • Allows for precision drawing but is limited to CRT technology.

Disadvantages of Light Pens

  • Restricted usability and technology.

Direct Data Entry Devices

  • Description: Devices that automate data input, minimizing human involvement.

Examples of DDE Devices

  • Barcode Readers, Card Readers.

Magnetic Stripe Readers

  • Description: Reads data from magnetic stripes on cards.

    • Uses: ATMs, security entry systems.

    • Advantages: Quick, error-free data entry, durable.

    • Disadvantages: Data loss when damaged, proximity required.

Contactless Card Readers

  • Description: Reads radio waves from contactless cards.

    • Uses: Transactions without PIN entry.

    • Advantages: Faster processing with encryption.

    • Disadvantages: Risk of unauthorized access.

Chip and PIN Readers

  • Description: Security system with physical card and PIN for transactions.

    • Advantages: High security via PIN verification.

    • Disadvantages: High potential for fraud if PIN is observed.

RFID Readers

  • Description: Uses radio waves to access data on RFID chips.

    • Advantages: No line-of-sight required, quick reading.

    • Disadvantages: Easy to jam or hack.

Optical Mark Recognition (OMR)

  • Description: Reads marks on forms.

    • Uses: Surveys, exams.

    • Advantages: Fast and accurate.

    • Disadvantages: Needs accurate form designs.

Optical Character Recognition (OCR)

  • Description: Converts text from hard copies to digital format.

    • Uses: Document processing, historic preservation.

    • Advantages: Faster than manual entry.

    • Disadvantages: Issues with handwriting recognition.

Barcode Readers

  • Description: Scans barcodes for data entry.

    • Uses: Retail, libraries.

    • Advantages: Quick and reduces mistakes.

    • Disadvantages: Can be damaged easily.

QR Code Scanners

  • Description: Reads square coded data for various applications.

    • Uses: Marketing, access to information.

    • Advantages: High information capacity, easy to generate.

    • Disadvantages: Can transmit malicious codes if created carelessly.

OUTPUT DEVICES AND THEIR USES

Monitors

  • Types: CRT (cathode ray tube) and LCD (liquid crystal display).

CRT Monitors

  • Advantages: Wide viewing angles, compatible with light pens.

    • Disadvantages: Heavy, consumes more power, larger footprint.

LCD Screens

  • Advantages: Energy-efficient, lightweight, no burn-in.

    • Disadvantages: View consistency issues, motion blur.

Touch Screens

  • Description: Dual-function device for input and output.

  • Uses: Smartphones, ATMs, kiosks.

Advantages of Touch Screens

  • Faster selections with user-friendly interfaces.

Disadvantages of Touch Screens

  • Limited options and can become dirty.

Multimedia Projectors

  • Description: Projects images from digital inputs.

  • Uses: Presentations, advertisements, home cinema.

Advantages of Multimedia Projectors

  • Enables group viewings.

Disadvantages of Multimedia Projectors

  • Potentially fuzzy images, setup difficulties.

Printers

Types:

  1. Laser Printers

    • Advantages: High speed, high-quality output, less running cost for large volumes.

    • Disadvantages: Initial high cost, health risks from emissions.

  2. Inkjet Printers

    • Advantages: High-quality output and low initial cost.

    • Disadvantages: Poor for high-volume jobs, expensive cartridges.

  3. Dot Matrix Printers

    • Advantages: Useful in dirty environments, cheap operation.

    • Disadvantages: Noisy, poor print quality compared to others.

Plotters

  • Description: Draws graphics with pens instead of printing.

  • Uses: Engineering, architectural drawings.

Advantages of Plotters

  • High accuracy and versatility with materials.

Disadvantages of Plotters

  • Typically slow and expensive.

3D Printers

  • Description: Builds objects layer by layer using various materials.

  • Uses: Prototyping in many fields including medicine and engineering.

Advantages of 3D Printers

  • Allows quick custom manufacturing and prototyping.

Disadvantages of 3D Printers

  • Risks of counterfeit and potential job losses due to manufacturing automation.

Speakers

  • Description: Convert digital audio into sound via DAC.

  • Uses: Computers, multimedia presentations.

Advantages of Speakers

  • Amplifies sound for group listening, aids in accessibility.

Disadvantages of Speakers

  • Can be disruptive in shared environments, quality can be costly.

Actuators

  • Description: Mechanisms that respond to inputs to control devices such as motors.

  • Uses: Control systems, robotics.

Advantages of Actuators

  • Facilitate remote operation.

Disadvantages of Actuators

  • Added complexity and potential points of failure in systems.