# 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.