Input and Output Devices Overview

Introduction to Input and Output Devices

  • Input: Data and instructions entered into the memory of a computer or mobile device.
    • Common input methods:
    • Keyboard
    • Pointing devices
    • Touch screens
    • Pen input
    • Motion input
    • Voice input
    • Video input
    • Scanners and reading devices

Keyboards

  • Definition: An input device with keys used to enter data/instructions.
  • Standard Keyboard Layout: Includes typing area, function keys, toggle keys, navigation keys, media control buttons, internet control buttons, and special keys.
  • Types of Keyboards:
    • Compact
    • On-screen/Virtual
    • Ergonomic (designed to prevent RSIs)
    • Gaming
    • Wireless

Pointing Devices

  • Definition: Devices used to control the position of the cursor on the screen.
  • Common Types:
    • Mouse:
    • Types: Optical mouse, laser mouse, touch mouse
    • Description: Fits under palm, used to move the cursor and interact with objects on screen.
    • Touchpad:
    • Description: Flat, pressure-sensitive area used primarily on laptops, responsive to finger movements.
    • Trackball:
    • Description: Stationary device with a ball on top used for navigation by rolling the ball.

Touch Screens

  • Definition: A display that is sensitive to touch, allowing users to interact directly by pressing buttons or icons on the screen.

Pen Input

  • Definition: Allows users to draw or write on a surface with a stylus or digital pen.
  • Examples:
    • Graphics Tablet: Converts movement of a stylus into signals for the computer, widely used in design fields.

Motion, Voice, and Video Input

  • Motion Input: Users guide on-screen elements with gestures through physical movement (gesture recognition).
  • Voice Input:
    • Description: Entering data by speaking into a microphone, also known as speech recognition.
  • Video Input:
    • Describes capturing images and storing them digitally (e.g., through video cameras).
    • Webcams: Used for video conferencing, capturing images, and sending video over the Internet.

Scanners and Reading Devices

  • Scanner: Reads printed text/graphics and converts them into digital data.
    • Types:
    • Flatbed Scanner
    • Optical Reader
    • Bar Code Reader (uses laser beams for reading)
    • QR Code Reader
    • RFID Reader
    • MICR Reader (for checks in banking)

Output

  • Definition: Data processed into usable formats (e.g., text, graphics, audio, video).
Displays
  • Definition: Devices for visually conveying information.
  • Types: LCD monitors, digital televisions (DTV), Smart TVs.
  • Quality Factors: Resolution, response time, brightness, dot pitch, contrast ratio.
Printers
  • Definition: Output devices producing physical text/graphics.
  • Types:
    • Non-impact Printers: Ink-jet, Laser, All-in-one, Photo Printers, etc.
    • Impact Printers: Physically striking the ink ribbon against paper.
  • Considerations Before Purchase: Type of prints needed, cost of ink, speed, and maintenance costs.
Other Output Devices
  • Speakers and Sound Systems: Used for audio outputs in computers and mobile devices.
  • Projectors: Project images from screens to larger displays for presentations.
  • Interactive Whiteboards: Enable touch interaction in presentations and learning.
  • Assistive Technology: Specialized input/output devices designed for accessibility and enhanced usability for users with disabilities.