Computer Input Devices | Meaning, Functions, Types, Keyboard & Mouse

What are computer Input Devices? Computer input devices are hardware components that allow users to interact with a computer system by providing data or instructions. These devices enable users to input information into the computer for processing, manipulation, and communication. Common examples of computer input devices include: 1. Keyboard: A primary input device used for […]

What are computer Input Devices?

Computer input devices are hardware components that allow users to interact with a computer system by providing data or instructions. These devices enable users to input information into the computer for processing, manipulation, and communication. Common examples of computer input devices include:

1. Keyboard: A primary input device used for typing text, entering commands, and navigating through software interfaces.
2. Mouse: A pointing device used to control the cursor on the screen, select items, and interact with graphical user interfaces (GUIs).
3. Touchscreen: A display screen that can detect and respond to touch gestures, allowing users to input commands directly through the screen.
4. Trackpad: A touch-sensitive pad on laptops and some desktop computers that functions similarly to a mouse for cursor control and gestures.
5. Graphics Tablet: A device used by artists and designers for drawing or handwriting input, typically with a stylus or pen.
6. Joystick: A device primarily used for controlling movement in video games or simulations, often featuring buttons or triggers for additional functions.
7. Scanner: A device used to convert physical documents, images, or objects into digital format by capturing their visual or textual content.
8. Microphone: An input device used to capture audio signals, allowing users to record sound, issue voice commands, or engage in voice communication.
9. Webcam: A camera device that captures video images, commonly used for video conferencing, live streaming, or recording video content.
10. Biometric Scanner: A device that reads unique biological characteristics such as fingerprints, iris patterns, or facial features for authentication and security purposes.

These input devices play a crucial role in enabling users to interact with computers and perform various tasks effectively.


Two Categories of Input Devices :

  1. Modality of input (e.g., mechanical motion, audio, visual, etc.).
  2. The nature of the input is discrete (e.g., keyboard) or continuous (e.g., mouse position).


Types of Input Devices: Modern and Earliest

Modern Input Devices:

Modern input devices are tools or mechanisms through which users interact with computers or electronic systems to input data or commands. Here’s an explanation of each of the mentioned modern input devices:

1. Camera: A camera captures visual information and converts it into digital data that can be stored, manipulated, or transmitted by a computer. It’s commonly used for photography, video recording, surveillance, and various other applications.

2. Compact disc (CD): Though primarily a storage medium, CDs can also function as an input device when used in conjunction with CD-ROM drives. They allow users to input data, such as software, music, or video files, into a computer system.

3. Keyboard: One of the most common input devices, a keyboard allows users to input text, numbers, and commands into a computer system by pressing keys. Keyboards can be physical or virtual (on-screen).

4. Mouse: A pointing device that allows users to interact with graphical user interfaces (GUIs) by moving a cursor on the screen and clicking on icons, buttons, or links. It typically has buttons and sometimes a scroll wheel for additional functionalities.

5. Scanner: A device that converts physical documents, images, or objects into digital images or data that can be stored, edited, or transmitted by a computer. Scanners are commonly used for tasks like digitizing documents, photos, and artwork.

6. Joystick: Primarily used in gaming and flight simulation, a joystick is a handheld input device that allows users to control the movement of objects on a screen by tilting or moving the joystick in different directions.

7. Barcode Scanner: A device that reads barcode symbols, typically found on products, and converts them into digital data that can be interpreted by a computer. Barcode scanners are used in retail, inventory management, and various other applications for quick and accurate data entry.

8. Microphone: An input device that converts sound waves into electrical signals, which can be processed, recorded, or transmitted by a computer. Microphones are used for voice input, speech recognition, recording audio, and communication purposes.

Other modern input devices may include touchscreens, graphic tablets, game controllers, virtual reality (VR) input devices, biometric scanners (such as fingerprint readers), and more, depending on specific applications and technological advancements.


Earliest Input Devices:

1. Punch Card: Punch cards were one of the earliest methods used to input data into early computers. They were made of stiff paper and contained holes punched in specific positions to represent data. Each hole position represented a piece of data or an instruction. These cards were widely used in early computing from the late 19th century through the mid-20th century.

2. Card Reader: A card reader is a device used to read data from punch cards. It typically consists of a mechanism that moves the card past a sensor that detects the presence or absence of holes in specific positions on the card. This data is then fed into the computer for processing.

3. Punched Paper Tape: Punched paper tape is similar to punch cards but in the form of a continuous strip of paper. Holes are punched in the paper at specific positions to represent data or instructions. Like punch cards, punched paper tape was widely used for data storage and input in early computing.

4. Magnetic Tape Unit: Magnetic tape units use magnetic tape as a medium for storing and inputting data. The tape is coated with a magnetic material, and data is stored as a series of magnetic impressions on the tape. Magnetic tape units typically consist of a tape drive that reads and writes data to the tape, allowing it to be used for input, output, and storage.

5. Optical Character Recognition (OCR): OCR is a technology that allows computers to interpret printed or handwritten text from scanned images or photographs. Early OCR systems were used to input text into computers by scanning printed documents and converting the text into digital format, allowing it to be processed and manipulated by software.

These input devices played crucial roles in the early days of computing, enabling users to input data and instructions into computers for processing and storage. They laid the foundation for the development of more advanced input technologies that we use today.


The Keyboard:

The keyboard serves as an input device for entering data into a computer system and remains a crucial interface between users and computers. It is an electronic device with groups of keys electronically linked to the processor when connected to a computer system.


Two Types of Keyboards:

  1. Standard Keyboard
  2. Enhanced Keyboard

Keyboard Designed Based Purposes

1. Standard Keyboards: These are the typical keyboards most people are familiar with, featuring alphanumeric keys, function keys, numeric keypad, and navigation keys.

2. Ergonomic Keyboards: Designed to reduce strain on the wrists and hands, ergonomic keyboards have a split or curved design to promote a more natural typing posture.

3. Mechanical Keyboards: Utilizing individual mechanical switches beneath each key, mechanical keyboards offer tactile feedback and are known for their durability and responsiveness. They’re popular among gamers and typists.

4. Membrane Keyboards: These keyboards use a membrane beneath the keys to register keystrokes. They are typically quieter and less expensive than mechanical keyboards but may lack the tactile feedback.

5. Wireless Keyboards: These keyboards connect to the computer via Bluetooth or other wireless technologies, offering freedom of movement and reducing cable clutter.

6. Gaming Keyboards: Optimized for gaming, these keyboards often feature customizable keys, backlighting, and macro support to enhance gaming performance.

7. Virtual Keyboards: Instead of physical keys, virtual keyboards are software-based interfaces that allow users to input text using touchscreens or other input devices.

8. Projection Keyboards: These keyboards project a virtual image of a keyboard onto a surface, enabling typing without physical keys. They’re often used with smartphones and tablets.

9. Compact Keyboards: Also known as mini or tenkeyless keyboards, these have a smaller form factor by omitting the numeric keypad, making them more portable and space-saving.

10. Programmable Keyboards: These keyboards allow users to customize the functions of individual keys or create macros for specific tasks, enhancing productivity and workflow efficiency.


Features of a Standard Keyboard:

  1. 10 function keys
  2. Four arrow keys
  3. 84-89 keys in total


Features of an Enhanced Keyboard:

  1. 12 function keys (F1-F12)
  2. Eight arrow keys
  3. 101-105 keys in total


Keyboard Sections:

The keyboard is segmented into five distinct sections:

  1. Alphanumeric Keys (Alphabet and Numbers): This section comprises the alphabet (a-z) and numerical digits (0-9).
  2. Function Keys F1-F12: These twelve keys, labeled F1-F12, are positioned horizontally on the first row of enhanced keyboards. On standard keyboards, they are labeled F1-F10.
  3. Control Keys – Del, Ctrl, Esc, and Alt: Used in conjunction with other keys to execute specific tasks.
  4. Cursor Control and Screen Movement Keys – Arrow, Home, End, Page Up, etc.: These keys enable the user to move the cursor left, right, up, and down lines.
  5. Numeric Keypad: Typically located at the extreme right-hand corner of modern keyboards, it exclusively contains numerical digits.


Keyboard Features:

1. Key Layout: Keyboards can have different layouts, with the QWERTY layout being the most common. Other layouts like AZERTY and Dvorak exist too.

2. Mechanical vs. Membrane: Keyboards can have mechanical switches, which offer tactile feedback and durability, or membrane switches, which are quieter and often cheaper.

3. Backlighting: Many keyboards have backlighting, which illuminates the keys for better visibility in low light conditions or for aesthetic purposes.

4. Programmable Keys: Some keyboards allow you to customize key functions or assign macros to specific keys for increased productivity.

5. Media Controls: Keyboards may include dedicated keys for controlling media playback, such as volume adjustment, play/pause, and track skipping.

6. USB Hub: Some keyboards come with built-in USB hubs, allowing you to connect other devices directly to the keyboard.

7. Wireless Connectivity: Wireless keyboards use Bluetooth or RF signals to connect to a computer, providing more flexibility in positioning and reducing cable clutter.

8. Ergonomic Design: Ergonomic keyboards are designed to reduce strain and discomfort during long typing sessions, often featuring split key layouts or curved designs.

9. Anti-Ghosting and N-Key Rollover: These features ensure that all key presses are registered accurately, even when multiple keys are pressed simultaneously, which is crucial for gaming and fast typing.

10. Wrist Rest: Some keyboards come with detachable or integrated wrist rests to provide ergonomic support and reduce wrist strain.

11. Specialized Keyboards: There are keyboards designed specifically for gaming, programming, or other specialized tasks, featuring additional keys or ergonomic layouts tailored to those activities.

12. Multilingual Support: Keyboards may have layouts and characters optimized for specific languages or regions.

13. Touchpad or Trackball: Some keyboards integrate a touchpad or trackball for mouse input, making them suitable for use in situations where a separate mouse is impractical.

14. Customizable Appearance: Certain keyboards allow users to customize the appearance by swapping keycaps or even the keyboard chassis itself.

These are just a few examples of the myriad features available in computer keyboards, catering to a wide range of preferences and needs.


Keyboard Uses:

  1. Enter text, numbers, and punctuation.
  2. In the absence of a mouse, it can be used to shut down the computer system.
  3. Ctrl + Alt + Del keys facilitate restarting the computer during warm booting.
  4. Shortcut Commands: Keyboards are often equipped with shortcut keys or combinations that provide quick access to various functions. For example:(a) Ctrl + C: Copy
    (b) Ctrl + V: Paste
    (c) Ctrl + X: Cut
    (d) Ctrl + Z: Undo
    (e) Ctrl + S: Save
  5. Navigating Interfaces: Keyboards can be used to navigate through interfaces and menus, especially in text-based environments or when accessibility features are enabled. For instance:
    (a) Arrow keys: Navigate through documents, web pages, or menus.
    (b) Tab key: Move between selectable items or fields.
    (c) Enter key: Confirm selections or execute commands.
  6. Media Controls: Many keyboards come with dedicated keys or combinations for controlling media playback:
    (a) Play/Pause, Stop, Next Track, Previous Track: Control audio or video playback.
    (b) Volume Control: Increase, decrease, or mute audio output.
  7. System Commands: Keyboards often facilitate various system-level commands beyond shutdown:
    (a) Alt + F4: Close active window or application.
    (b) Windows key (on Windows OS): Opens the Start menu for quick access to programs and settings.
    (c) Command key (on macOS): Opens Spotlight search or other system functions.
  8. Function Keys (F1-F12): These keys have different functions depending on the context, such as adjusting brightness, controlling wireless connections, or launching specific applications.
  9. Programming and Development: For programmers and developers, keyboards play a crucial role in coding and debugging with shortcuts for tasks like:
    (a) Commenting/uncommenting code blocks.
    (b) Indentation and code formatting.
    (c) Debugging commands and breakpoints.
  10. Gaming Controls: In gaming, keyboards often serve as primary input devices, offering customizable keys and macros for controlling in-game actions.
  11. Accessibility Features: Keyboards can be customized with accessibility features like sticky keys, filter keys, or on-screen keyboards to assist users with disabilities.
  12. Text Editing and Formatting: Beyond basic typing, keyboards enable various text editing and formatting functions like selecting text, changing font styles, and applying formatting options like bold or italic.
  13. Macro Support: Some keyboards allow users to program macros, enabling the execution of complex sequences of commands or keystrokes with a single key press. This can be useful for automating repetitive tasks or enhancing productivity in certain workflows.



The mouse, like the keyboard, serves as an interface for communication with a computer screen, utilized for drawing and plotting images. Mice are categorized into two types:

  1. Optical Mouse
  2. Ball Track Mouse


Basic Mouse Functions:

  1. Clicking: Quickly pressing and releasing a mouse button once.
  2. Double Clicking: Rapidly pressing and releasing the mouse button twice.
  3. Dragging: Holding down a mouse button while moving an object.
  4. Pointing: Moving the mouse pointer to touch an item.
  5. Scrolling: Using the mouse wheel to move up or down within a document or webpage.
  6. Right-clicking: Pressing the secondary button on the mouse, typically used to access context menus or perform secondary actions.
  7. Hovering: Moving the mouse pointer over an item without clicking, often to display additional information or tooltips.
  8. Context Menu: Accessing a menu of options specific to the item under the mouse pointer by right-clicking.Highlighting: Clicking and dragging the mouse to select text or objects on the screen.
  9. Contextual Drag-and-Drop: Dragging an item while holding down a specific keyboard key (e.g., Ctrl key on Windows) to perform a specific action when dropping the item.
  10. Gesture Controls: Utilizing specific mouse movements, such as swiping or pinching, to perform actions like navigating between pages or zooming in/out.
  11. Custom Button Mapping: Configuring additional functions to mouse buttons beyond their default actions, often done through software or driver settings.
  12. Precision Mode: Holding down a key (e.g., Shift key) while moving the mouse to slow down cursor movement for more precise actions, useful in graphic design or gaming.
  13. Mouse Acceleration: Adjusting the sensitivity of the mouse movement based on the speed at which it’s moved, often customizable in mouse settings.
  14. Mouse Macros: Recording a sequence of mouse movements and clicks to be replayed later with a single action, commonly used in gaming or repetitive tasks.


Mouse Features:

1. Buttons: Most mice have at least two buttons, typically a left-click and a right-click. Some mice have additional buttons, including a middle button or scroll wheel that can also act as a button.

2. Scroll Wheel: Found between the left and right buttons, the scroll wheel allows for easy vertical scrolling through documents and web pages. Some mice also offer horizontal scrolling capabilities.

3. DPI (Dots Per Inch) Sensitivity: DPI refers to the sensitivity of the mouse’s movement. Higher DPI settings allow for faster cursor movement with less physical movement of the mouse.

4. Ergonomic Design: Many mice are designed with ergonomics in mind to provide comfort during extended use. This may include contours to fit the hand, rubberized grips, and customizable shapes.

5. Wireless Connectivity: Wireless mice use Bluetooth or RF (radio frequency) technology to connect to the computer, providing freedom of movement without being tethered by a cable.

6. Rechargeable Batteries: Some wireless mice come with rechargeable batteries, eliminating the need for disposable batteries and reducing environmental waste.

7. Programmable Buttons: Gaming mice often feature programmable buttons that can be customized to perform specific functions or macros, providing shortcuts for gaming or productivity tasks.

8. Ambidextrous Design: Ambidextrous mice are designed to be comfortable for both left-handed and right-handed users, with symmetrical button layouts and shapes.

9. Surface Compatibility: Some mice are designed specifically for certain surfaces, such as optical mice that work best on opaque surfaces and laser mice that can function on a wider range of surfaces.

10. Adjustable Weight: Gaming mice may come with removable weights that allow users to customize the weight and balance of the mouse to their preferences.

11. RGB Lighting: Many gaming mice feature customizable RGB lighting that can be adjusted to match a user’s setup or preferences, adding a stylish flair to the peripheral.


Mouse Operations:

1. Pointing: Moving the mouse to position the cursor on the screen. This is the most basic operation and is essential for interacting with graphical user interfaces (GUIs).

2. Click: Pressing and releasing the primary mouse button (usually the left button) to select an object or execute a command. A single click is often used to open files, select icons, or activate interface elements.

3. Double-click: Quickly pressing and releasing the primary mouse button twice in succession. This action is typically used to open files or launch applications.

4. Right-click: Pressing and releasing the secondary mouse button (usually the right button) to access context menus. Right-clicking on an object or in a blank area of the screen brings up options relevant to the selected item or location.

5. Drag and Drop: Clicking and holding the mouse button while moving the mouse to select and move an object on the screen. Once the object is in the desired location, releasing the mouse button drops the object in that position. This operation is commonly used for rearranging files, organizing folders, or moving items within applications.

6. Scrolling: Using the scroll wheel (often found between the two main mouse buttons) to navigate through documents or web pages vertically. Scrolling up moves content upward, while scrolling down moves content downward.

7. Hovering: Moving the mouse cursor over an object without clicking. Hovering can trigger interactive elements such as tooltips, dropdown menus, or pop-up information boxes.

8. Context Menus: Accessing additional options and functionality by right-clicking on an object or area of the screen. Context menus provide context-sensitive actions relevant to the current selection or location.

These are some of the primary mouse operations, but modern mice may also feature additional buttons or functionalities, such as side buttons, DPI adjustment, or customizable shortcuts, which can expand the range of operations and enhance user interaction.

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