Hardware Reference
In-Depth Information
ergonomic designs, and the more recent models even use the same optical tracking mech-
anisms used by the latest Microsoft and Logitech mice.
The largest manufacturers of mice are Microsoft and Logitech; these two companies
provide designs that inspire the rest of the industry and each other and are popular OEM
choices as well as retail brands. Even though mice can come in different varieties, their
actual use and care differ very little. The standard mouse consists of several components:
• A housing that you hold in your hand and move around on your desktop.
•Amethodoftransmittingmovementtothesystem:eitherball/rolleroropticalsensors.
• Buttons (two or more, and often a wheel or toggle switch) for making selections.
•Wheelforverticalscrolling.Somewheelstiltforhorizontalscrollingorcanbepressed
to act as a button.
• An interface for connecting the mouse to the system. Conventional mice use a wire
and connector, whereas wireless mice use a radio frequency (RF) or infrared (IR)
transceiver in both the mouse and a separate unit connected to the computer to inter-
face the mouse to the computer.
The housing, which is made of plastic, consists of few moving parts. On top of the hous-
ing, where your fingers normally rest, are buttons. There might be any number of but-
tons, but mice designed for PCs have always had two buttons, and since 1996 they have
a scroll wheel as well. Although the latest versions of Windows support scrolling mice,
otherfeaturessupportedbythevendor,includingadditionalbuttons,stillrequireinstalling
the vendor's own mouse driver software.
Ball-Type Mice
The bottom of the mouse housing is where the detection mechanisms or electronics are
located. On traditional mice, the bottom of the housing contains a small, rubber ball that
rolls as you move the mouse across the tabletop. The movements of this rubber ball are
translated into electrical signals transmitted to the computer across the cable.
Internally,aball-drivenmouseissimple.Theballusuallyrestsagainsttworollers:onefor
translating the x-axis movement and the other for translating the y-axis movement. These
rollersaretypicallyconnectedtosmalldiskswithshuttersthatalternatelyblockandallow
the passage of light. Small optical sensors detect movement of the wheels by watching an
internal IR light blink on and off as the shutter wheel rotates and “chops” the light. These
blinks are translated into movement along the axes. Ball type mice are considered obsol-
ete today, although many are still in use.
