Discuss various device based controls.

Various device-based controls :

1. Trackball:
   • What: A ball that moves freely in all directions in a socket.
   • How: Rotate the ball with fingertips to move the on-screen cursor.
   • Useful for: Navigational control in video games or 3-D environments.
2. Joystick:
   • What: Stick or bat-shaped device anchored at the bottom.
   • Sizes: Come in various sizes, operated by fingers or the whole hand.
   • Types: Some are immovable (respond to pressure), others movable (within a dish-shaped area).
   • Useful for: Fine or gross coordination tasks, mounted on keyboards.
3. Graphic Tablet:
   • What: Horizontal surface sensitive to pressure, heat, light, or blockage of light.
   • How: Operated with fingers, stylus, or other objects. Mimics movement on the screen.
   • Useful for: Graphic design and precise input tasks.
4. Light Pen:
   • What: Utilizes a touch screen sensitive to a specific pen or stylus.
   • How: Similar to a graphic tablet, but with a specific pen or stylus.
5. Touch Screen:
   • What: Screen sensitive to finger or stylus touch.
   • How: Point and touch objects on the screen for selection.
   • Useful for: Direct interaction with on-screen elements.
6. Voice:
   • What: Automatic speech recognition technology.
   • How: Recognizes and processes spoken commands.
   • Useful for: Hands-free control, especially in situations where manual input is impractical.
7. Mouse:
   • What: Movable desktop control with one to three buttons.
   • How: Move the mouse to control the on-screen pointer.
   • Useful for: Manipulating objects and information on the screen.