Chapter 5: Input - Discovering Computers 2012

Overview of Input and Instructions

• Input: Any data and instructions entered into the memory of a computer.
• Instructions: Entered into a computer system in three primary forms:
  • Program: A series of related instructions that tells a computer what tasks to perform and how to perform them. Programs respond to commands issued by users.
  • Command: An instruction that causes a program to perform a specific action.
  • User Response: An instruction a user issues by replying to a question displayed by a program.
• Input Device: Any hardware component that allows users to enter data and instructions into a computer.

Keyboards and Layouts

• Keyboard: An input device containing keys that users press to enter data and instructions into a computer.
• Standard Desktop Keyboard Features:
  • Contains between $101$ and $105$ keys.
  • Typing Area: Main key layout containing alphanumeric characters and standard typing keys.
  • Numeric Keypad: Positioned on the right side of the keyboard for efficient numerical data entry.
  • Function Keys: Special keys assigned specific commands ($F1$, $F2$, etc.).
  • Control and Modifier Keys: Includes CTRL keys, ALT keys, and WINDOWS key.
  • Application Key: Opens shortcut menus corresponding to the current selection.
  • Toggle Keys: Keys that switch between two states, such as NUM LOCK key and CAPS LOCK key.
  • Cursor / Navigation Controls: Includes arrow keys, Page Up, Page Down, Home, End, Insert, and Delete keys.
  • Additional / Media Controls: Media playback controls, internet control keys, and special feature keys (such as an $F3$ key configured as Redo).
  • Wrist Rest: Integrated ergonomic support at the base of the keyboard to prevent wrist strain.

• Insertion Point (Cursor): A symbol on the screen that indicates where the next typed character will appear. Its appearance changes depending on the task being performed.
• Keyboard Connection Types:
  • Wired Keyboards: Connect directly to the system unit via a USB port.
  • Wireless Keyboards: Connect without physical cables using:
  • Bluetooth technology.
  • IrDA (Infrared Data Association) line-of-sight communication.
• Ergonomic Keyboard Design:
  • Ergonomics: The science that incorporates comfort, efficiency, and safety into the design of the workplace.
  • Designed to reduce the risk of repetitive strain injuries (RSIs) such as tendonitis and Carpal Tunnel Syndrome (CTS), which involve inflammation of tendons or nerve compression in the wrist and hand.
• Mobile Device Keyboards:
  • Typically smaller in size and feature fewer keys than standard desktop keyboards.
  • Key types on mobile hardware:
  • On-Screen Keyboard: Virtual touch keypads displayed on screen.
  • Mini-Keyboard: Small tactile hardware keyboards embedded or slid out from devices.
  • Keypad: Standard numeric/alphanumeric keypad layout.
  • Predictive Text Input: Software feature that anticipates words being typed to save time when entering text via a keypad.

Pointing Devices and Mouse Operations

• Pointing Device: An input device that allows a user to control a pointer on the screen.
• Pointer: A small symbol on the screen whose location and shape change as a user moves a pointing device.
• Mouse: A pointing device designed to fit comfortably under the palm of a user's hand. It is the most widely used pointing device on desktop computers and can be wired or wireless.
• Mouse Controls:
  • Left mouse button
  • Right mouse button
  • Wheel button (center scroll wheel)
  • Thumb buttons (side navigation controls)
• Standard Mouse Operations:
  • Point: Move the mouse to position the pointer over an item on the screen.
  • Click: Press and release the primary (left) button.
  • Right-Click: Press and release the secondary (right) button to open a context menu.
  • Double-Click: Quickly press and release the primary mouse button twice.
  • Triple-Click: Quickly press and release the primary mouse button three times to select standard paragraphs.
  • Drag: Press and hold the left mouse button, move the object, and release the button.
  • Right-Drag: Press and hold the right mouse button while moving an item to bring up a context menu upon release.
  • Rotate Wheel: Roll the wheel forward or backward to scroll through documents.
  • Free-Spin Wheel: Disengage wheel resistance for hyper-fast scrolling.
  • Press Wheel: Click the wheel down to enable auto-scrolling.
  • Tilt Wheel: Push the wheel side-to-side to scroll horizontally.
  • Press Thumb Button: Perform custom programmed macros or browser forward/back commands.
• Other Pointing Devices:
  • Trackball: A stationary pointing device with a sphere on its top or side that the user rotates with fingers or palm.
  • Touchpad: A small, flat, rectangular pointing device sensitive to pressure and motion.
  • Pointing Stick: A pressure-sensitive device shaped like a pencil eraser, located between keys on a keyboard.

Touch Screens and Touch-Sensitive Surfaces

• Touch Screen: A touch-sensitive display device that reacts to physical contact from a finger or gesture.
  • Integrated into self-service airport check-in kiosks, smart phones, desktop monitors, and interactive surface computers.
• Multi-Touch Table / Surface Computers: Large horizontal touch screens (such as Microsoft Surface) that allow multiple users to interact simultaneously using hands and gestures.
• Touch-Sensitive Pad: Input pads found on portable media devices (e.g., click wheels on media players) that respond to sliding finger motions and pressing buttons.

Pen and Smart Phone Input

• Pen Input: Entering data by touching a stylus or digital pen onto a flat surface to write, draw, or make selections.
• Pen-Based Hardware Devices:
  • Stylus: A small plastic or metal instrument that looks like a ballpoint pen but uses pressure or electronic signals instead of ink. Dual-function styluses can act as a screen pen on one end and a ballpoint pen on the other.
  • Signature Capture Pad: Used to capture handwritten signatures electronically at point-of-sale or delivery locations.
  • Graphics Tablet: An electronic plastic board that detects the movement of a digital pen, enabling digital drawing and design.
• Smartphone Input Features:
  • Handheld navigation receivers attached to windows to obtain maps and directions.
  • External portable/wireless keyboards connected via Bluetooth.
  • Headset microphones communicating wirelessly to accept speech commands.
  • Integrated rear-facing digital cameras for capturing photos.
  • Direct cable connections to transfer data and instructions to and from computers.

Game Controllers

• Game Controller: An input device used to direct movements and actions of on-screen objects in video games and computer games.

• Types of Game Controllers:
  • Gamepad: Held with both hands; controls actions using thumb buttons and directional pads.
  • Joystick: Vertical lever mounted on a base that steers objects in multi-directional space.
  • Wheel and Pedals: Steering wheel and foot pedal setup used to simulate driving controls.
  • Light Gun: Aimed at a monitor to detect target light sources in shooting games.
  • Dance Pad: Flat electronic pad divided into pressure-sensitive direction zones pressed by feet.
  • Motion-Sensing Controller: Wireless hand unit (e.g., Wii Remote) containing accelerometers to guide actions based on motion.
  • Balance Board: Floor board that senses weight shifts and body balance.
  • Guitar Controller: Musical instrument replica with fret buttons and strum bar for rhythm games.

Digital Cameras

• Digital Camera: A mobile device that captures photographs and stores them in a digital format.
• Camera Categories:
  • Studio Cameras: High-end stationary cameras attached to computers for professional studio photography.
  • Field Cameras: Portable high-quality cameras used by photojournalists.
  • Point-and-Shoot Cameras: Compact, automated cameras for everyday handheld use.

• How a Digital Camera Works:
  1. Step 1: The user points the lens at an image and triggers the shutter; light enters the lens.
  2. Step 2: Light focuses onto an image sensor chip called a Charge-Coupled Device (CCD).
  3. Step 3: The CCD generates an analog electrical signal representing the light intensity and color of the image.
  4. Step 4: An Analog-to-Digital Converter (ADC) converts the analog signal into a binary digital signal.
  5. Step 5: An internal processor adjusts image quality settings and writes the digital photo file onto memory media inserted in the camera.
• Factors Determining Photo Quality:
  • Resolution: The total number of horizontal and vertical pixels contained within a display or image.
  • Pixel: The smallest individual element in an electronic display or image matrix.
  • Color Depth (Bit Depth): The number of bits stored in each pixel. More bits per pixel allow a greater range of color representations and shades of gray.

Voice and Audio Input

• Voice Input: The process of entering data or instructions by speaking into a microphone.
• Voice Recognition: A computer system's ability to distinguish, interpret, and process spoken words (e.g., speech-to-text programs like Dragon NaturallySpeaking).
• Audio Input: The process of entering any sound into the computer, categorized into:
  • Speech
  • Music
  • Sound Effects
• Music Production Software: Digital audio workstations used to record, compose, sequence, mix, and edit audio tracks and musical compositions.

Video Input

• Video Input: The process of capturing full-motion images and saving them onto a computer's storage medium.
• Video Digitizing Pipeline:
  • Capture footage on a Digital Video (DV) camera, or route analog video signals through a video capture card to convert them to digital.
  • Connect the camera to a computer using a high-speed USB or FireWire port.
  • Transfer video files for editing, playback, or distribution.

• Web Cam: A compact digital video camera connected to a computer that enables users to:
  • Capture video footage and still photographs.
  • Send e-mail messages containing video attachments.
  • Add live video streams to instant messaging applications.
  • Broadcast video over the Internet.
  • Conduct real-time video telephone calls.
• Video Conference: A real-time virtual meeting between two or more geographically separated individuals using network-connected video feeds, microphones, and displays.

Scanners and Optical Reading Devices

• Optical Scanners: Devices that capture light reflections from paper documents to convert text and graphics into digital data.
• Scanner Configurations:
  • Flatbed Scanner: Document rests face down on a glass bed while a scanning mechanism moves beneath it.
  • Pen / Handheld Scanner: Portable device dragged manually across text.
  • Sheet-fed Scanner: Documents are pulled continuously through feed rollers.
  • Drum Scanner: High-resolution rotating drum system used for publishing.

• How a Flatbed Scanner Works:
  1. Step 1: Place the document face down on the glass window and start the process using buttons or software.
  2. Step 2: The scanner converts physical content into digital data and transmits it across a interface cable into computer memory.
  3. Step 3: Computer memory stores the file, allowing users to view, edit, print, e-mail, embed, or publish the image online.
• Optical Character Recognition (OCR):
  • Hardware and software designed to read printed characters from paper sources.
  • Uses standardized OCR font characters.
  • Turnaround Document: A document created by a business, sent to a customer, and returned with payment or information (e.g., utility or credit card bill stubs printed with OCR readable numbers).

• Optical Mark Recognition (OMR): Devices that detect hand-drawn marks on paper sheets (such as filled-in bubbles or rectangles on standardized tests and voting ballots) by analyzing light absorption patterns.
• Bar Code Reader (Bar Code Scanner): Optical device using laser beams to read linear (1-D) or matrix (2-D / QR code) bar codes.
• Radio Frequency Identification (RFID):
  • Employs radio signals to communicate with an electronic tag attached to or embedded within an item.
  • RFID readers retrieve unique data stored on tags via radio waves.
  • Tracked Applications:
  • Marathon runner split times.
  • Military personnel tracking.
  • Uniforms and employee wardrobes.
  • Airline baggage routing.
  • Ski lift pass validation.
  • Real-time warehouse inventory management.
  • Vehicle tire pressure and temperature telemetry.
  • Library book circulation checkout.
  • Electronic highway toll processing.
• Magnetic Stripe Card Reader: Reads encoded financial or personal data stored inside the magnetic stripe on the back of credit cards, debit cards, identity badges, and entertainment cards.
• Magnetic Ink Character Recognition (MICR):
  • Converts characters printed with special magnetized ink into digital form.
  • Used extensively by the banking industry for automated check processing.
  • Parses essential check fields: Bank Routing Number, Account Number, Check Number, and Check Amount.

• Data Collection Devices: Portable or ruggedized readers that capture transaction data at the exact point of occurrence in environments such as restaurants, retail stores, factories, distribution warehouses, and outdoors.

Biometric Input

• Biometrics: Technology that authenticates an individual's identity by scanning and verifying unique biological characteristics.
• Biometric Systems:
  • Fingerprint Reader: Captures ridge patterns on fingertips.
  • Face Recognition System: Analyzes facial structures and feature proportions.
  • Hand Geometry System: Measures physical dimensions of palm and fingers.
  • Voice Verification System: Matches voice pitch, tone, and cadence.
  • Signature Verification System: Evaluates shape, speed, and pressure of handwriting.
  • Iris Recognition System: Scans detailed patterns within the iris of the eye.
  • Retinal Scanner: Maps blood vessel networks located at the back of the retina.

Terminals and Self-Service Kiosks

• Terminal: A computer workstation that transmits data to and receives information from a host main processing server.
• Common Specialized Terminals:
  • POS (Point of Sale) Terminal: Records retail purchases, calculates sales totals, processes credit/debit payments, and updates store inventory databases automatically.
  • Automated Teller Machine (ATM): Self-service banking terminal connected to a central banking network for account management and cash processing.
  • DVD Kiosk: Self-service automated machine used to browse, rent, and return video media via a touch screen.

Summary of Input Devices by User Type

• Home User:
  • Enhanced keyboard or ergonomic keyboard.
  • Mouse.
  • Stylus for smart phone or mobile device.
  • Game controller(s).
  • $30\text{-bit } 600 \times 1200\text{ ppi}$ color scanner.
  • $7\text{ MP}$ digital camera.
  • Headset with microphone.
  • Web cam.
  • Fingerprint reader.
• Small Office / Home Office (SOHO):
  • Enhanced keyboard or ergonomic keyboard.
  • Mouse.
  • Stylus and portable keyboard for smart phone, or digital pen for Tablet PC.
  • $36\text{-bit } 600 \times 1200\text{ ppi}$ color scanner.
  • $8\text{ MP}$ digital camera.
  • Headset with microphone.
  • Web cam.
• Mobile User:
  • Wireless mouse for notebook computer.
  • Touchpad or pointing stick integrated into notebook.
  • Stylus and portable keyboard for smart phone, or digital pen for Tablet PC.
  • $7\text{ MP}$ or $8\text{ MP}$ digital camera.
  • Headset with microphone.
  • Notebook fingerprint reader.
• Power User:
  • Enhanced keyboard or ergonomic keyboard.
  • Mouse.
  • Stylus and portable keyboard for smart phone.
  • Pen for graphics tablet.
  • $48\text{-bit } 1200 \times 1200\text{ ppi}$ color scanner.
  • $9\text{ MP}$ to $12\text{ MP}$ digital camera.
  • Headset with microphone.
  • Web cam.
• Enterprise User:
  • Enhanced keyboard or ergonomic keyboard.
  • Mouse.
  • Stylus and portable keyboard for smart phone, or digital pen for Tablet PC.
  • Touch screen display.
  • $42\text{-bit } 1200 \times 1200\text{ ppi}$ color scanner.
  • $9\text{ MP}$ to $12\text{ MP}$ digital camera.
  • OCR/OMR readers, bar code readers, MICR reader, or portable data collection devices.
  • Dedicated microphone.
  • Video conference camera system.
  • Fingerprint reader or other biometric authenticators.

Accessibility Input Devices

• Input Hardware for Physically Challenged Users:
  • Keyguard: A metal or plastic plate fitted over a keyboard with holes over each key to prevent accidental keystrokes.
  • Keyboards with Larger Keys: Oversized keys for users with limited motor control.
  • On-Screen Keyboard: Software keyboard navigated via alternate pointer controls.
  • Alternative Pointing Devices: Trackballs, foot switches, or mouth-operated joysticks.
  • Head-Mounted Pointer: System where an optical camera mounted on the monitor tracks a reflective surface attached to the brim of a user's hat to position the cursor.
  • Gesture Recognition: Computer vision software that translates physical body movements into system commands.
  • Computerized Implant Devices: Microchips implanted directly to route neural impulses into digital inputs.