Input Devices

1. What an input device is

• A device that sends data from the user (or environment) into the computer for processing.
• Without input devices the user cannot interact with the computer.

2. Categories

• Manual input – keyboard, mouse, touchscreen.
• Pointing devices – mouse, trackpad, joystick, stylus, graphic tablet.
• Imaging – scanner, camera, webcam.
• Audio – microphone.
• Biometric – fingerprint reader, face recognition, iris scanner.
• Sensors – temperature, motion, light (mainly in IoT and mobile devices).

3. Keyboard

• The most common text input device.
• Layouts: QWERTY (US/UK), QWERTZ (CZ, DE), AZERTY (FR), Dvorak.
• Types: membrane, mechanical (with switches – Cherry MX), scissor (laptops), virtual (touchscreen).
• Connections: wired (USB, PS/2), wireless (Bluetooth, 2.4 GHz dongle).
• Special keys: function keys (F1–F12), modifier keys (Ctrl, Alt, Shift), navigation, numeric keypad.

4. Mouse

• Used to move the cursor and click.
• Types: mechanical (old, ball), optical (LED + sensor), laser (more precise), trackball.
• Connections: USB, Bluetooth, wireless USB dongle.
• Modern mice have several buttons + scroll wheel; gaming mice add DPI controls and extra buttons.

5. Touchscreens

• Combine input and output – they display content and detect touch.
• Resistive – older, pressure-based, single-touch.
• Capacitive – modern, multi-touch, used in smartphones and tablets.
• Now common in laptops, kiosks, ATMs, car infotainment.

6. Graphics tablet / pen / stylus

• Used by artists, designers, architects.
• Pen has pressure sensitivity.
• Brands: Wacom, Huion, XP-Pen, Apple Pencil for iPad.

7. Scanner

• Converts physical documents or images into digital format.
• Flatbed scanner – books, photos.
• Sheetfed scanner – many documents quickly.
• 3D scanner – creates 3D models of objects.
• Barcode scanner / QR code scanner – shops, warehouses.
• OCR (Optical Character Recognition) turns scanned text into editable text.

8. Camera & webcam

• Webcam – built-in (laptops) or external, used for video calls, streaming.
• DSLR / mirrorless cameras – professional photography.
• Smartphone cameras – the most-used cameras today.
• Used as input for video conferencing, security, computer vision (AI).

9. Microphone

• Converts sound to electrical signal.
• Types: condenser (studio), dynamic (live), USB, lavalier (clip-on), array (in smartphones).
• Used for: voice calls, recording, dictation, voice assistants (Siri, Alexa).

10. Biometric devices

• Fingerprint reader – laptops, smartphones (Touch ID).
• Face recognition – Face ID, Windows Hello.
• Iris / retina scanner – very secure, used in some companies.
• Voice recognition – also a form of biometrics.

11. Game controllers

• Joystick, gamepad (Xbox, PlayStation), steering wheel, flight stick.
• Motion controllers: Wii Remote, PlayStation Move, VR controllers.
• VR/AR – full-body tracking with handsets and headsets.

12. Sensors (IoT)

• Light, temperature, humidity, motion, gyroscope, accelerometer, GPS.
• Found in smartphones, smart homes, cars, industrial IoT.

13. Useful vocabulary

• Click, double-click, drag and drop, scroll, swipe, pinch, tap.
• Cursor, pointer, hotkey, shortcut, layout.
• Wired vs. wireless, latency, polling rate, DPI / sensitivity.

14. Speaking strategy

Define input devices and list categories. Talk about keyboard and mouse in detail. Then mention touchscreens, scanners, cameras, microphones, biometrics. Finish with sensors / IoT to sound modern.