Input

Text input devices
Keyboard - a device to input text and characters by depressing buttons (referred to as keys).
Pointing devices
Mouse - a pointing device that detects two dimensional motion relative to its supporting surface.
Optical Mouse - uses light to determine mouse motion.
Trackball - a pointing device consisting of an exposed protruding ball housed in a socket that detects rotation about two axes.
Touchscreen - senses the user pressing directly on the display
Gaming devices
Joystick - a control device that consists of a handheld stick that pivots around one end, to detect angles in two or three dimensions.
Gamepad - a handheld game controller that relies on the digits (especially thumbs) to provide input.
Game controller - a specific type of controller specialized for certain gaming purposes.
Image, Video input devices
Image scanner - a device that provides input by analyzing images, printed text, handwriting, or an object.
Webcam - a low resolution video camera used to provide visual input that can be easily transferred over the internet.
Audio input devices
Microphone - an acoustic sensor that provides input by converting sound into electrical signals