Like its namesake, the computer mouse has proliferated. There are one-, two-, three-, and five-button models. Some use a light beam rather than a ball; some have a scroll wheel; and some are wireless, working off radio frequencies. There are even models that vibrate, providing tactile feedback. Let's review a little history, basic mouse technology, and some features of the latest models.
The mouse is an input device used to move the pointer (cursor) on your monitor's screen. It is the most popular of the four major pointing devices: mouse, trackball, pointing stick, and touch pad. It was invented by Douglas Engelbart of the Stanford Research Center in 1963 and used by Xerox in the 1970s. It was called a mouse because it resembled one, with the cord being its tail.
The mouse uses a combination of hardware and software to produce and control the movement of the cursor on the monitor's screen. A software device driver generates the cursor and controls its position. As the mouse is moved around, hardware signals are generated and transmitted to the device driver, which moves the cursor in a similar manner. By positioning the cursor over a graphic symbol on the screen and activating one of the buttons on the mouse, one can select (click or double-click) and manipulate (drag) options in the application program instead of using the keyboard.
The most common type of mouse is the mechanical type. It has a rubber ball on its underside that can roll in all directions. The ball is nudged up against a pair of perpendicular roller bars that move when the ball moves. The roller bars generate positive or negative pulses, depending on the direction of travel. These pulses are transmitted to the computer's mouse driver software, where the signals are converted to cursor position on the screen. Mouse movement as little as 1/400th of an inch can be detected.
In the optical mouse, the old-fashioned mouse ball has been replaced with an optical sensor that tracks mouse movement. The optical sensor is sealed to keep out dirt and lint that can cause the traditional mouse to skip or jam. Early versions of the optical mouse required a special mat with a grid so that the optical mechanism had a fixed frame of reference. However, modern versions require no special pad; motion can be detected on hundreds of surfaces, including wood, plastic, or even your pant leg.
A recent addition to the mouse is the scrolling wheel. This is a small wheel that has been inserted between the left and right mouse buttons. Turning the wheel with your finger causes programs, such as web browsers, to scroll up and down. Pressing the wheel down may also provide access to other functions, depending on what the manufacturer has programmed into the driver.
If you do not like having your mouse tethered to a cable, you can use a cordless mouse. This mouse has two components, the mouse itself (without a tail) and a radio receiver. The receiver has the cord and is attached to the computer. The receiver can be located somewhere out of the way. The mouse, either mechanical or optical, can be used normally without the nuisance of a cable. The mouse signals are transmitted via a radio frequency to the receiver, where they are relayed to the computer by cable. I've been using a cordless mouse for several months and have been quite pleased with it. One disadvantage is that a pair of batteries is needed to power the mouse.
One of the latest additions to the mouse world is the vibrating mouse. A small motor spins inside the mouse, varying speed and duration in response to a stimulus. Some models are programmed to vibrate when the cursor moves over icons, menus, hyperlinks, and bookmarks. Other models vibrate in response to PC-generated sounds.
Four types of mouse interfaces are common: serial, PS/2, USB, and bus mice. The first three types are straightforward. The mouse cable is terminated with a serial connector, PS/2 connector, or an USB connector that plugs into the appropriate port on the computer. In those cases where one of the above ports is not available, one can use a bus mouse. This type of mouse uses a stand-alone controller board that is inserted into one of the computer's expansion slots. The mouse cable then plugs into a connector on the board.
There is a little-known feature of Windows (95, 98, Me), called MouseKeys, that allows one to use the numeric keypad to move the cursor around the screen, click, double-click, and drag. This feature is useful if you're caught without a mouse. Go to Control Panel and double-click on the Accessibility icon and select the Mouse tab. You can enable or disable MouseKeys by checking or clearing the check box. Use the eight outer keys of the numeric keypad to move the cursor. To left click, press the 5 key. Pressing the minus key puts you in the right click mode; use the 5 key again. To switch back to the left click, use the slash key. To drag, press the Insert key at the bottom of the keypad. To release it, press the slash key.
A number of companies have web sites that provide descriptive information on their line of mouse products, as well as other pointing devices. These include IBM Corp, Kensington Corp, Logitech Corp, and Microsoft Corp.
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