List of input devices:

• The keyboard

  The keyboard is an input device that enables the user to enter characters (letters, numbers and symbols) into a computer. It consists of rows of keys with each key representing a different character.
  There are different types of keyboards available, for example, QWERTY keyboards, ergonomic keyboards, Braille keyboards.

  
  

• The mouse

  The mouse is an input device used to specify the position of the cursor or to make choices from menus. As you move the mouse, the cursor on the display screen moves in the same direction. Mice contain one or more buttons. Newer mice also include a scroll wheel for scrolling through long documents. The mouse is important for graphical user interfaces because you can simply point to options and objects and click a mouse button. It is also useful for graphics programs that allow you to draw pictures by using the mouse like a pen, pencil, or paintbrush.
  See the mouse actions

  
  

• The scanner

  

  Using a scanner, you can input printed drawings, photographs or text directly into electronic codes that can be understood by the computer. A scanner works like a photocopier – a light is shone on the material and the scanner detects the reflected light. The image is read as the series of dots and then the digitised image is generated and stored as a file

• The trackball

  

  The trackball or the trackerball works in exactly the same way as a mouse, but the ball is on top. The user rolls the ball around with his hand. They are often used on small portable computers or video game machines.
  
  

• The graphics tablet

  

  The graphics tablet is an input device which is often used by graphics designers and illustrators.
  It has two parts – an electronic tablet with a flat surface and a special pen - stylus. The tablet can sense how the pen is moving around on its flat surface. By moving the pen around you are able to draw lines and pictures.

• The lightpen

  

  The lightpen is similar to an ordinary pen. It works by detecting light from the computer screen. It allows the user to draw pictures, diagrams or graphics directly on the screen display

• The joystick

  

  Joystick is a type of pointing device usually used for playing games. It has a gear like lever which is able to move in eight directions and control the movement of a pointer or some other display symbol. There is a button on the top of a lever which is used for selection. In industries it is used to control the robot and also in flight simulation training.

• The barcode reader

  

  Barcode Reader is a type of electronic device used for reading data in the form of bars and strips. It utilizes the laser beam of light that is sensitive to the reflections from the strips, space thickness and variation and translates the reflected optical impulses into digital data. Bar codes are used for labeling goods in big stores. After scanning the code, it transmits the data to store’s computer, which located the current price, updates the stock and prints the receipt for the customer.

• The touchpad

  

  The touchpad is small, touch-sensitive pad used as a pointing device on some portable computers. By moving a finger or other object along the pad, you can move the pointer on the display screen. And you click by tapping the pad.
  
  

• The touch screen

  

  The touch screen is a type of display screen that has a touch-sensitive transparent surface. Instead of using a pointing device such as a mouse or light pen, you can use your finger to point directly to objects on the screen. Such displays can be attached to computers, or to networks as terminals. They also play a prominent role in the design of digital appliances such as the personal digital assistant (PDA), satellite navigation devices, mobile phones, and video games.

• The webcam

  

  This is a small video camera, about the size of a golf ball that can send video pictures when attached to a computer with the right software. Web Cams are used for video conferencing or to monitor something from across the Internet.
  
  

• The microphone

  

  A microphone converts sound into an electrical signal. Sound is basically rapidly changing air pressure and so a microphone contains a 'diaphragm' that moves back and forth as the sound waves hit it. This movement is detected by some electronics which produces an electrical signal. This signal is then fed into a sound card or audio amplifier.