Know and understand characteristics, uses, advantages and disadvantages of input devices including keyboard, numeric keypad, pointing devices, remote control, joystick/driving wheel, touch screen (as an input device), scanners, camera, microphone, se

2 Input and Output Devices – Input Devices

Keyboard

The keyboard is the most common text‑input device. It consists of a set of alphanumeric keys, function keys, and control keys.

• Characteristics: QWERTY layout, mechanical or membrane switches, optional back‑lighting.
• Uses: Typing documents, entering data into spreadsheets, programming, gaming.
• Advantages: Familiar to most users, high typing speed, low cost.
• Disadvantages: Can cause repetitive‑strain injury, not suitable for users with limited hand mobility.

Numeric Keypad

A separate block of keys (0‑9, decimal point, arithmetic operators) designed for rapid numeric entry.

• Characteristics: Usually on the right side of a full‑size keyboard, may be detachable.
• Uses: Accounting, data entry, calculator functions.
• Advantages: Faster numeric input than using the main keyboard.
• Disadvantages: Takes extra space; not needed for all users.

Pointing Devices

Devices that translate hand movement into cursor movement on a screen.

• Types: Mouse, touchpad, trackball, graphics tablet.
• Characteristics: Optical or laser sensor, wired or wireless.
• Uses: Selecting icons, drawing, gaming.
• Advantages: Precise control, ergonomic designs available.
• Disadvantages: Requires a flat surface (mouse), may be less accurate on glossy screens.

Remote Control

Hand‑held device that sends infrared (IR) or radio‑frequency (RF) signals to control electronic equipment.

• Characteristics: Buttons for power, volume, channel, menu navigation; may include a numeric keypad.
• Uses: Television, set‑top boxes, media players, smart home devices.
• Advantages: Allows operation from a distance, simple interface.
• Disadvantages: Line‑of‑sight required for IR, limited functionality compared with full keyboards.

Joystick / Driving Wheel

Specialised pointing devices used mainly for gaming and simulation.

• Characteristics: Stick that pivots on two axes; driving wheels mimic steering wheels with pedals.
• Uses: Flight simulators, racing games, CAD navigation.
• Advantages: Provides realistic control, high precision for specific applications.
• Disadvantages: Bulky, expensive, limited use outside gaming/simulation.

Touch Screen (as an Input Device)

A display that detects the presence and location of a touch.

• Characteristics: Capacitive or resistive technology, supports multi‑touch gestures.
• Uses: Smartphones, tablets, kiosks, interactive whiteboards.
• Advantages: Direct interaction, intuitive for many users, reduces need for peripheral devices.
• Disadvantages: Can be less accurate than a mouse, fingerprints may reduce visibility, higher cost.

Scanners

Devices that convert physical documents or images into digital data.

• Characteristics: Flat‑bed, sheet‑fed, optical resolution measured in DPI.
• Uses: Archiving paper records, OCR (optical character recognition), digitising photos.
• Advantages: Fast conversion of large volumes, preserves original documents.
• Disadvantages: Requires proper lighting and maintenance, limited to 2‑D input.

Camera (Webcam / Digital Camera)

Captures still images or video and converts them into digital signals.

• Characteristics: Resolution (megapixels), frame rate (fps), built‑in microphone.
• Uses: Video conferencing, photography, image input for OCR.
• Advantages: Enables visual communication, can be integrated into laptops.
• Disadvantages: Dependent on lighting, privacy concerns.

Microphone

Converts sound waves into electrical signals for digital processing.

• Characteristics: Directional (omnidirectional, cardioid), analog or digital output.
• Uses: Voice recording, speech‑to‑text, video narration.
• Advantages: Hands‑free input, essential for accessibility.
• Disadvantages: Susceptible to background noise, requires proper placement.

Sensors

Devices that detect physical phenomena and convert them into electrical signals.

• Types: Temperature, light, motion, pressure, proximity.
• Characteristics: Output often expressed as voltage \$V\$ proportional to measured quantity \$Q\$, e.g., \$V = kQ\$.
• Uses: Environmental monitoring, interactive installations, smart devices.
• Advantages: Enables automation, can capture data not possible with manual input.
• Disadvantages: Calibration required, may be affected by environmental interference.

Light Pen

A handheld pointing device that detects light from a CRT or LCD screen.

• Characteristics: Emits a light source; screen detects the point of contact.
• Uses: Drawing, selecting objects on a screen, educational tools.
• Advantages: Direct interaction with screen, high precision.
• Disadvantages: Requires compatible display, can cause eye strain.

Summary Table