Chapter 3: Input and Output Devices

Input Devices

  • Definition of Input: Any data or instructions used by a computer.
  • Input devices translate data into a form that the system unit can process.
  • Examples of hardware input devices:
    • Keyboards
    • Mice
    • Pointing devices
    • Scanning devices
    • Image capturing devices
    • Audio-input devices

Keyboard Entry

  • Types of Keyboards:
    • Traditional keyboards
    • Laptop keyboards
    • Virtual keyboards
    • Thumb keyboards
  • Keyboard features:
    • Function keys: Shortcuts for specific tasks (e.g., F1 for Help).
    • Numeric keypad: Enters numbers and arithmetic symbols, controls cursor.
    • Windows key: Displays the Start menu.
    • Navigation keys: Control the cursor.

Pointing Devices

  • Provide an intuitive interface by accepting pointing gestures and converting them into machine-readable input.
  • Wide variety of devices:
    • Mouse
    • Touch screen
    • Game controller
    • Stylus
Mouse Types
  • Optical mouse:
    • No moving parts.
    • Emits and senses light to detect movement.
    • Can be used on any surface.
  • Wireless mouse:
    • Battery operated.
    • Uses radio waves or infrared light waves.
  • Touch pads:
    • Controls pointer by moving and tapping fingers on the surface.
Touch Screen
  • Can be touched with more than one finger.
  • Common on mobile devices.
    *Example : Apple iPhone
Tablets
  • Stylus:
    • Pen-like device used on tablets.
    • Uses handwriting recognition software.

Gaming Controllers

  • Provide input to computer games.
    • Joysticks: Use pressure and direction of the stick.
    • Gaming mice: Similar to a mouse but with high precision.
    • Game pads: Use both hands.
    • Motion sensing devices: Control games by user movement.

Scanning Devices

  • Convert scanned data into a form the system unit can process.
  • Types:
    • Optical scanners
    • Flatbed scanners
    • Document scanners
    • Portable scanners
    • 3D scanners
Card Readers
  • Interpret encoded information on cards.
    • Magnetic card reader: Reads information from a magnetic strip when swiped.
    • Smart cards: Hold additional security information.
      Example : Credit cards, entertainment cards and bank cards.
Bar Code Readers
  • Contain photoelectric cells to scan bar codes.
    • **Wand readers & Hand-held readers:
      *UPCs:* Used in grocery stores for checkout and inventory.
    • MaxiCode: Used by shipping companies for routing packages.
    • QR codes: Store information vertically and horizontally.
RFID Readers
  • Radio-Frequency Identification (RFID): Tiny chips embedded in objects contain electronically stored information that can be read using an RFID reader.
  • RFID applications:
    • Tracking runners in a marathon.
    • Tracking location of people and items.
    • Checking lift tickets of skiers.
    • Managing inventory.
    • Gauging temperature and pressure of tires.
    • Checking out library books.
    • Providing access to rooms or buildings.
    • Managing purchases.
    • Tracking payment on tollways.
Character and Mark Recognition Readers
  • Recognize special characters and marks.
    • Magnetic-ink character recognition (MICR): Used by banks to read characters on checks.
    • Optical-character recognition (OCR): Reads preprinted characters (wand scanners).
    • Optical-mark recognition (OMR): Senses the presence or absence of marks (test scoring).
NFC Reader
  • NFC (Near Field Communication): A protocol based on RFID for close-range radio signals between two devices.
  • Range is short, usually an inch or less.
  • Uses:
    • Commerce
    • User identification
    • Security
      Example : Google Wallet with MasterCard PayPass.
  • NFC tags can be programmed to perform tasks like turning off Wi-Fi or enabling silent mode on a phone when scanned to save battery.

Image Capturing Devices

  • Create or capture original images.
    • Digital Camera: Capture images digitally and store in memory.
    • Web Cams: Capture images and send them to a computer for broadcast over the Internet.

Audio-Input Devices

  • Voice recognition systems use a microphone, sound card, and special software.
  • Users can operate computers and create documents using voice commands.
  • Included in many smartphones: Siri (iPhones), Cortana (Windows phones), Google Now (Google phones).

Biometrics Authentication

  • Authenticates a person’s identity by translating a personal characteristic into a digital code for comparison.
    • Examples:
      • Fingerprint reader
      • Face recognition system
      • Hand geometry system
      • Voice verification system
      • Signature verification system
      • Iris recognition system

Output Devices

  • Definition of Output: Processed data or information.
  • Types of outputs: Text, graphics/photos, audio & video.
  • Output devices: Monitors, printers, audio-output devices.

Monitors

  • Known as screens or display screens; present visual images.
  • Output referred to as soft copy.
  • Features: Clarity, resolution/pixels, dot pitch, contrast ratios, size, aspect ratio.
Monitor Types
  • Flat-panel monitors:
    • Require less power.
    • Portable and thin.
    • Backlit.
      • Liquid Crystal Display (LCD): Older monitors.
      • Light Emitting Diode (LED): More advanced backlighting.
      • Organic Light Emitting Diode (OLED): Thin layer organic compound that produces light.
  • Curved Monitors
    • Provide better viewing angles near the edges of the screen
    • Used by high-end gamers and smart watches
E-book Readers
  • E-books are traditional books in electronic form.
  • E-book readers are dedicated mobile devices for storing and displaying e-books.
  • Use e-ink technology that reflects light.
    Example : Kindle and Nook.
Other Monitor Types
  • Digital/interactive whiteboards: Connect to a computer or projector; controlled with a pen or finger.
  • Ultra High-definition television (UHDTV): Digital output delivering a clearer and more detailed image.
  • Digital Projector: Project the images from a traditional monitor onto a screen or wall

Printers

  • Translates information processed by the system unit onto a physical medium.
  • Output referred to as hard copy.
  • Features: Resolution, color, speed, memory, duplex printing.
  • Types: Impact and nonimpact printers.
Non-Impact Printers
  • Forms characters and graphics without striking the paper.
    • Ink-jet printers: spray tiny drops of liquid ink.
      • Color or black-and-white.
      • Higher dpi produces higher quality output.
      • Reliable, quite and inexpensive
    • Photo printers:* create photographs.
      • Use inkjet or dye-sublimation technology.
      • PictBridge allows direct printing from a digital camera.
      • Print from memory card and preview photos on a built-in LCD screen.
    • Laser printers: use a laser light beam.
      • Fast, excellent quality.
    • Thermal printers: generate images by pushing heated pins against heat-sensitive paper.
    • Mobile printers: small, lightweight, battery-powered for wireless printing.
    • Plotters: produce high-quality drawings.
Impact Printer
  • Impact printers: form characters and graphics by striking a mechanism against an inked ribbon that physically contacts the paper
    • Dot-matrix printer: uses tiny wire pins on a print head.
    • Line printer: prints output a line at a time.
    • Daisy-wheel printer: rotates a disk with characters in relief along the outer edge.
Comparison between Impact & Non-impact Printers
  • IMPACT PRINTER
    • Text or image is formed in contact of paper and the printer head.
    • Noisy, slow and poor quality output.
    • These printers are cheap.
    • Example – Dot matrix, line, daisy wheel and etc.
  • NON-IMPACT PRINTER
    • Text or image is formed without any physical contact of the paper and the printer head.
    • Noiseless, fast and high quality output.
    • These printers are expensive.
    • Example – Laser , Ink-jet, thermal, photo, plotter and etc.
Other Printers
  • All-in-one printer: prints, scans, copies, and sometimes faxes.
  • 3D Printers
    • Create 3-D shapes with a thin layer of material repeatedly until created
    • 3D printing or additive manufacturing is a process of making three dimensional solid objects from a digital file .
  • Tools for 3D Printer Processing
    • 3D scanners use different technologies to generate a 3D model (3D digital copy of object).
    • 3D modeling software - CAD (Computer Aided Design) 3D modeling software making virtual design of the object.
    • Example : Blender, Tinkercard
  • Cloud printers: connected to the Internet; provide printing services to others on the Internet.
    Example : Google Cloud Print
  • Braille printer

Audio and Video Devices

  • Translates audio information from the computer into sounds people can understand.
    • Speakers and headphones
    • Bluetooth Technology: Wireless technology to connect to speakers and headsets.

Other Output Devices

  • Data projector: projects text and images from a computer or mobile device onto a larger screen.
  • Interactive whiteboard: touch-sensitive device that displays the image on a connected computer screen.

Combination of Input and Output Devices

  • Headsets: Combine a microphone and headphones.
  • Multifunctional devices (MFD): Cost efficient but lower quality. All-in-one printers are an example.
Telephones
  • Known as Telephony and Internet Telephony
  • Voice-over IP (VoIP)
    Example : Hangouts, Face Time, Skype
Smart Watches
  • Combine input and output capabilities
  • Offer features like heart rate monitoring, step-counting, call reminders, and notifications
Drones and Robots
  • Drones: Take input from a controller and send back video and sound to the user.
  • Robots: Use microphones, cameras, and sensors as input; output depends on the robot's use.
    • Assists in surgery
    • Virtual Reality Created in 3D through computers for a virtual experience. Headgear with gloves have sensors to collect data that work with software.
Input and Output Devices for Physically Challenged Users
  • Head-mounted pointer
  • Braille printer

A Look to the Future

  • Augmented Reality Displays With wearable augmented reality displays, data from your computer and the Internet will be instantly viewable. Funding for development from the government has begun to assist soldiers and pilots.
    Example : Google has developed a prototype, “Project Glass”, that is being tested.