The purpose of the input hardware is to collect data and convert it into a form suitable for computer processing. The most common input device is a keyboard.It looks very much like a typewriter. The mouseis a hand held device connected to the computer by small cable. As the mouse is rolled across the mouse pad, the cursor moves across the screen. When the cursor reaches the desired location, the user usually pushes a button on the mouse once or twice to signal a menu selection or a command to the computer.
The light penuses a light sensitive photoelectric cell to signal screen position to the computer. Another type of input hardware is optic-electronic scannerthat is used to input graphics as well as typeset characters. Microphoneand video cameracan be also used to input data into the computer. Electronic cameras are becoming very popular among the consumers for their relatively low price and convenience.