Mouse

In computing, a mouse (plural mouses, mice, or mouse devices) is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features can add more control or dimensional input. The mouse's motion typically translates into the motion of a pointer on a display, which allows for fine control of a Graphical User Interface.

The first marketed integrated mouse – shipped as a part of a computer and intended for personal computer navigation – came with the Xerox 8010 Star Information System in 1981. However, the mouse remained relatively obscure until the appearance of the Apple Macintosh; in 1984 a prominent PC columnist commented the release of this new computer with a mouse: “There is no evidence that people want to use these things.” A mouse now comes with most computers and many other varieties can be bought separately.

Several other experimental pointing-devices developed for Engelbart's oN-Line System (NLS) exploited different body movements – for example, head-mounted devices attached to the chin or nose – but ultimately the mouse won out because of its simplicity and convenience. The first mouse, a bulky device (pictured) used two gear-wheels perpendicular to each other: the rotation of each wheel translated into motion along one axis. Engelbart received patent US3541541 on November 17, 1970 for an "X-Y Position Indicator for a Display System". At the time, Engelbart envisaged that users would hold the mouse continuously in one hand and type on a five-key chord keyset with the other. The concept was preceded in the 19th century by the telautograph, which also anticipated the fax machine.

The ball mouse utilizes two rollers rolling against two sides of the ball. One roller detects the forward–backward motion of the mouse and other the left–right motion. The motion of these two rollers causes two disc-like encoder wheels to rotate, interrupting optical beams to generate electrical signals. The mouse sends these signals to the computer system by means of connecting wires. The driver software in the system converts the signals into motion of the mouse pointer along X and Y axes on the screen.

The color of the optical mouse's light-emitting diodes varies with each model. Red was (and still is today) the most common, as red diodes were the cheapest when optical mice first arrived on the market. Today, a wide array of colors exist, such as blue or green. Some models' diodes even change color, cycling through colors of the rainbow for instance. Some models of laser mice can track on glossy and transparent surfaces, and have a much higher sensitivity than either their mechanical or optical counterparts but are more expensive than their LED based or mechanical counterparts.