Bill English, builder of the original mouse, invented the so-called ball mouse in 1972 while working for Xerox PARC. The ball-mouse replaced the external wheels with a single ball that could rotate in any direction. It came as part of the hardware package of the Xerox Alto computer. Perpendicular chopper wheels housed inside the mouse's body chopped beams of light on the way to light sensors, thus detecting in their turn the motion of the ball. This variant of the mouse resembled an inverted trackball and became the predominant form used with personal computers throughout the 1980s and 1990s. The Xerox PARC group also settled on the modern technique of using both hands to type on a full-size keyboard and grabbing the mouse when required.
The ball mouse utilizes two rollers rolling against two sides of the ball. One roller detects the horizontal motion of the mouse and other the vertical 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.
Modern computer mice took form at the École polytechnique fédérale de Lausanne (EPFL) under the inspiration of Professor Jean-Daniel Nicoud and at the hands of engineer and watchmaker André Guignard.This new design incorporated a single hard rubber mouseball and three buttons, and remained a common design until the mainstream adoption of the scroll-wheel mouse during the 1990s.
Honeywell produced another type of mechanical mouse.Instead of a ball, it had two plastic "feet" on the bottom which sensed movement. Keytronic later produced a similar product.
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An optical mouse uses a light-emitting diode and photodiodes to detect movement relative to the underlying surface, rather than moving some of its parts — as in a mechanical mouse.
Early optical mice, circa 1980, came in two different varieties:
1. Some, such as those invented by Steve Kirsch[11][12] of Mouse Systems Corporation, used an infrared LED and a four-quadrant infrared sensor to detect grid lines printed with infrared absorbing ink on a special metallic surface. Predictive algorithms in the CPU of the mouse calculated the speed and direction over the grid.
2. Others, invented by Richard F. Lyon and sold by Xerox, used a 16-pixel visible-light image sensor with integrated motion detection on the same chip[13] and tracked the motion of light dots in a dark field of a printed paper or similar mouse pad.[14]
These two mouse types had very different behaviors, as the Kirsch mouse used an x-y coordinate system embedded in the pad, and would not work correctly when rotated, while the Lyon mouse used the x-y coordinate system of the mouse body, as mechanical mice do.
As computing power grew cheaper, it became possible to embed more powerful special-purpose image-processing chips in the mouse itself. This advance enabled the mouse to detect relative motion on a wide variety of surfaces, translating the movement of the mouse into the movement of the pointer and eliminating the need for a special mouse-pad. This advance paved the way for widespread adoption of optical mice.
Modern surface-independent optical mice work by using an optoelectronic sensor to take successive pictures of the surface on which the mouse operates. Most of these mice use LEDs to illuminate the surface that they track over; marketers often mislabel LED optical mice as "laser mice". Changes between one frame and the next are processed by the image processing part of the chip and translated into movement on the two axes using an optical flow estimation algorithm. For example, the Agilent Technologies ADNS-2610 optical mouse sensor processes 1512 frames per second: each frame consisting of a rectangular array of 18×18 pixels, and each pixel can sense 64 different levels of gray.[15]
Optomechanical mice detect movements of the ball optically, giving the precision of optical without the surface compatibility problems, whereas optical mice detect movement relative to the surface by examining the light reflected off it.
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As early as 1998, Sun Microsystems provided a laser mouse with their Sun SPARCstation servers and workstations.[16] However, laser mice did not enter the mainstream market until 2004, when Logitech, in partnership with Agilent Technologies, introduced the laser mouse with its MX 1000 model. This mouse uses a small infrared laser instead of an LED, which increases the resolution of the image taken by the mouse. This leads to around 20× more sensitivity to the surface features used for navigation compared to conventional optical mice, via interference effects.[17]
Engineers designed the laser mouse — as a wireless mouse — to save as much power as possible. In order to do this, the mouse blinks the laser when in standby-mode (Each mouse has a different standby time). This function also increases the laser life. Laser mice designed specifically for gamers, such as the Logitech G5 or the Razer Copperhead, appeared later and lack this feature, in an attempt to reduce latency and to improve responsiveness.