An input device is any machine that feeds data into a computer.

Keyboard


The computer keyboard is the basic device through which you input information into the system. Though many other forms of inputting devices have come out in the market today, there is nothing equivalent to the keyboard.

Using the keyboard is easy because most of them have the QWERTY typewriter setup. In addition to the typing keys, the keyboard also has a numeric keypad through which you can input numbers. It has control keys like Home, Page Up, Page Down, Insert, Delete, End, Control (CTRL), Alternate (ALT), and Escape (ESC) that let you carry out these simple tasks with just one click.

Mouse


A mouse is a handheld pointing device for computers, involving a small object fitted with one or more buttons and shaped to sit naturally under the hand. The underside of the mouse houses a device that detects the mouse's motion relative to the flat surface on which it sits. The mouse's 2D motion is typically translated into the motion of a cursor on the display.

Track Ball


This is basically a mouse lying on its back. To move the pointer, you rotate the ball with your thumb, your fingers, or the palm of your hand. There are usually one to three buttons next to the ball, which you use just like mouse buttons.

Joystick

This is a computer input device especially helpful when playing computer games. It consists of a handle that can be pointed in different directions. Because the computer can sense which direction the joystick is pointed, it can be used to control the movements of objects displayed on the computer screen.

Scanner


A scanner is an external device used to record data on to the computer. The data can include photographs, book pages, and other images already on a piece of paper. The scanner is like a copy machine, but instead of printing the item on a piece of a paper, the digital image gets placed on the computer screen. Items are scanned, transmitted from the scanner to the computer.