Computer Mouse The
basic computer mouse is an amazingly clever invention with a relatively simple
design that allows us to point at things on the computer and it is very
productive. Think of all the things you can do with a mouse like selecting text
for copying and pasting, drawing, and even scrolling on the page with the newer
mice with the wheel. Most of us use the computer mouse daily without stopping to
think how it works until it gets dirty and we have to learn how to clean it. We
learn to point at things before we learn to speak, so the mouse is a very
natural pointing device. Other computer pointing devices include light pens,
graphics tablets and touch screens, but the mouse is still our
workhorse. The computer mouse was invented in 1964 by Douglas
Englehart of Stanford University. As computer screens became more popular and
arrow keys were used to move around a body of text, it became clear that a
pointing device that allowed easier motion through the text and even selection
of text would be very useful. The introduction of the mouse, with the Apple Lisa
computer in 1983, really started the computer public on the road to relying on
the mouse for routine computer tasks. How does the mouse work
We have to start at the bottom, so think upside down for now. It all starts with
the mouse ball. As the mouse ball in the bottom of the mouse rolls over the
mouse pad, it presses against and turns two shafts. The shafts are connected to
wheels with several small holes in them. The wheels have a pair of small
electronic light-emitting devices called light-emitting diodes (LED) mounted on
either side. One LED sends a light beam to the LED on the other side. As the
wheels spin and a hole rotates by, the light beam gets through to the LED on the
other side. But a moment later the light beam is blocked until the next hole is
in place. The LED detects a changing pattern of light, converts the pattern into
an electronic signal, and sends the signal to the computer through wires in a
cable that goes out of the mouse body. This cable is the tail that helps give
the mouse its name. The computer interprets the signal to tell it where to
position the cursor on the computer screen. So far we have only
discussed the basic computer mouse that most of you probably have or have used.
One problem with this design is that the mouse gets dirty as the ball rolls over
the surface and pieks up dirt. Eventually you have to clean your mouse. The
newer optical mice avoid this problem by having no moving parts. The most durable computer mice on sale are the IBM ones.