Input Devices

Definition

An Input Device is a piece of hardware used to provide data and control signals to an information processing system (like a computer). It allows the user to communicate with the computer.

Common Input Devices

1. Keyboard

• Function: The most primary input device used to enter text, numbers, and commands.

• Structure: It contains keys for letters, numbers, special characters, and function keys (F1-F12). The most common layout is QWERTY.

• Types: Wired, Wireless, Ergonomic, Virtual (on screens).

2. Mouse

• Function: A hand-held pointing device that detects two-dimensional motion relative to a surface. It controls the cursor (pointer) on the screen.

• Actions: Click (select), Double-click (open), Right-click (context menu), Drag and Drop.

• Types:

  • Optical Mouse: Uses a light/laser sensor (most common today).

  • Mechanical Mouse: Used a rubber ball (obsolete).

  • Trackball: The ball is on top; you move the ball with your thumb instead of moving the device.

3. Scanner

• Function: Converts physical documents (photos, text pages) into digital images (soft copy) so they can be stored or edited on the computer.

• Types:

  • Flatbed Scanner: like a photocopier machine.

  • Handheld Scanner: Portable, dragged over the text.

4. Special Reading Devices (Important for Exams)

These are used for specific data entry tasks, often in business or education.

• Barcode Reader: Scans vertical black and white lines (barcodes) on products to read pricing and inventory data (used in malls/shops).

• OMR (Optical Mark Reader): Detects marks on paper. Widely used for grading multiple-choice exam answer sheets.

• MICR (Magnetic Ink Character Recognition): Reads characters printed with magnetic ink. Used almost exclusively in banking to process cheques (the numbers at the bottom of a cheque).

• OCR (Optical Character Recognition): Software/Hardware that converts scanned images of text into editable text files.

5. Microphone

• Function: An input device that captures audio by converting sound waves into electrical signals.

• Uses: Voice recording, online chatting, voice recognition software (like Siri or Google Assistant).

6. Webcam

• Function: A digital video camera connected to a computer.

• Uses: Video conferencing (Zoom/Skype), facial recognition security, and live streaming.

7. Joystick & Gamepad

• Function: A pointing device mainly used for playing video games or controlling machines (like cranes or simulators).

• Mechanism: It has a vertical stick that can be moved in different directions to control an object on the screen.


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8. Touchscreen

• Function: A display screen that is also an input device. Users interact by touching pictures or words on the screen.

• Uses: Smartphones, tablets, ATMs, and ticket kiosks.