HOW DOES IT WORK

HOW A MOUSE WORKS

The optical mechanical mouse's operation is fairly simple. As you can see in the below illustration, the mouse movement is tracked by four parts. As the mouse is moved, the ball rolls in the direction of the movement which, in turn, moves the roller (X or Y axis). As the roller begins to rotate, so does the chopper / gear. The gear has small notches within it or around the edges of it; as it rotates, light shines through the openings which is then detected by the two light sensors which then sends the computer a signal of that movement. The offset of the light received by the two light sensors determines the direction of each axis.

Within the mouse you will find a total of two rollers and choppers / gears. Each roller represents a X or Y axis which is the Horizontal or Vertical movement of the mouse cursor.

MOUSE DISASSEMBLY

The illustration below shows the disassembly of a standard mouse. As shown you can see that the internal components of a mouse. We have illustrated the general location of four main components within the mouse.

First, you will notice the two Choppers and or Gears; these two represent the axis of where the cursor is located. The chopper furthest to the represents the X axis, which is the vertical axis. The other chopper, which is only partially shown, represents the Y axis, which is the horizontal axis.

Second, you notice the mouse ball. The mouse ball is the main part within the mouse which allows the user to move the mouse which moves the appropriate axis which then moves the mouse cursor on the screen. Without the mouse ball the mouse would be useless.

Third, you notice the four pin Interface Cable Connection, which is where the information is transferred from the mouse to the computer.

MOUSE TECHNOLOGIES

Mechanical Mice - Mechanical Mice requires that the mouse be set on a flat surface. The distance and the speed of the rollers inside the mouse determines how far the mouse cursor moves on the screen depending on the software configuration.

Optical Mice - Optical Mice require a special mouse pad which has a grid pattern. A sensor inside the mouse determines the movement by reading the grid as the mouse passes over it while emitting a light from an LED or sometimes a laser. This type of mouse is much more accurate than the ordinary optical mechanical mouse which relies on the traction between the mouse ball and the rollers. One drawback to an optical mouse is they can have problems in bright lights.

New Optical Mice no longer have the disadvantages of earlier mice and are capable of being utilized on any surface. In comparison to the traditional Optical-Mechanical mouse, the Optical is a much better solution for a computer mouse.

Optical-Mechanical - The optical-mechanical hybrid consists of a ball which rolls a wheel inside the mouse. This wheel contains a circle of holes and or notches to read the LED by a sensor as it spins around when the mouse is moved. This mouse is much more accurate than the mechanical mouse. This mouse is now the most commonly used mouse with PC and Macintosh computers. See How a mouse works for an illustration and a more in-depth explanation of how this mouse works.

MOUSE TECHNOLOGIES

Track down these parts:
monitor
mouse
tower
keyboard
headset
microphone
printer
scanner
numeric keypad
space bar
CD drive
floppy drive
power buttons (3 shown + 1 on side of scanner)
mouse pad
volume control (on keyboard)
power indicator lights

computer

A programmable machine. The two principal characteristics of a computer are:
It responds to a specific set of instructions in a well-defined manner.
It can execute a prerecorded list of instructions (a program).
Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.
All general-purpose computers require the following hardware components:
memory : Enables a computer to store, at least temporarily, data and programs.
mass storage device : Allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.
input device : Usually a keyboard and mouse, the input device is the conduit through which data and instructions enter a computer.
output device : A display screen, printer, or other device that lets you see what the computer has accomplished.
central processing unit (CPU): The heart of the computer, this is the component that actually executes instructions.
In addition to these components, many others make it possible for the basic components to work together efficiently. For example, every computer requires a bus that transmits data from one part of the computer to another.
Computers can be generally classified by size and power as follows, though there is considerable overlap:
personal computer : A small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.
workstation : A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.
minicomputer : A multi-user computer capable of supporting from 10 to hundreds of users simultaneously.
mainframe : A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.
supercomputer : An extremely fast computer that can perform hundreds of millions of instructions per second.

HISTORY OF COMPUTERS

An Illustrated History of Computers Part
___________________________________
John Kopplin © 2002
The first computers were people! That is, electronic computers (and the earlier mechanical computers) were given this name because they performed the work that had previously been assigned to people. "Computer" was originally a job title: it was used to describe those human beings (predominantly women) whose job it was to perform the repetitive calculations required to compute such things as navigational tables, tide charts, and planetary positions for astronomical almanacs. Imagine you had a job where hour after hour, day after day, you were to do nothing but compute multiplications. Boredom would quickly set in, leading to carelessness, leading to mistakes. And even on your best days you wouldn't be producing answers very fast. Therefore, inventors have been searching for hundreds of years for a way to mechanize (that is, find a mechanism that can perform) this task.

This picture shows what were known as "counting tables" [photo courtesy IBM]

A typical computer operation back when computers were people.
The abacus was an early aid for mathematical computations. Its only value is that it aids the memory of the human performing the calculation. A skilled abacus operator can work on addition and subtraction problems at the speed of a person equipped with a hand calculator (multiplication and division are slower). The abacus is often wrongly attributed to China. In fact, the oldest surviving abacus was used in 300 B.C. by the Babylonians. The abacus is still in use today, principally in the far east. A modern abacus consists of rings that slide over rods, but the older one pictured below dates from the time when pebbles were used for counting (the word "calculus" comes from the Latin word for pebble).

A very old abacus

A more modern abacus. Note how the abacus is really just a representation of the human fingers: the 5 lower rings on each rod represent the 5 fingers and the 2 upper rings represent the 2 hands.
In 1617 an eccentric (some say mad) Scotsman named John Napier invented logarithms, which are a technology that allows multiplication to be performed via addition. The magic ingredient is the logarithm of each operand, which was originally obtained from a printed table. But Napier also invented an alternative to tables, where the logarithm values were carved on ivory sticks which are now called Napier's Bones.

An original set of Napier's Bones [photo courtesy IBM]

A more modern set of Napier's Bones
Napier's invention led directly to the slide rule, first built in England in 1632 and still in use in the 1960's by the NASA engineers of the Mercury, Gemini, and Apollo programs which landed men on the moon.

A slide rule
Leonardo da Vinci (1452-1519) made drawings of gear-driven calculating machines but apparently never built any.

A Leonardo da Vinci drawing showing gears arranged for computing
The first gear-driven calculating machine to actually be built was probably the calculating clock, so named by its inventor, the German professor Wilhelm Schickard in 1623. This device got little publicity because Schickard died soon afterward in the bubonic plague.

Schickard's Calculating Clock
In 1642 Blaise Pascal, at age 19, invented the Pascaline as an aid for his father who was a tax collector. Pascal built 50 of this gear-driven one-function calculator (it could only add) but couldn't sell many because of their exorbitant cost and because they really weren't that accurate (at that time it was not possible to fabricate gears with the required precision). Up until the present age when car dashboards went digital, the odometer portion of a car's speedometer used the very same mechanism as the Pascaline to increment the next wheel after each full revolution of the prior wheel. Pascal was a child prodigy. At the age of 12, he was discovered doing his version of Euclid's thirty-second proposition on the kitchen floor. Pascal went on to invent probability theory, the hydraulic press, and the syringe. Shown below is an 8 digit version of the Pascaline, and two views of a 6 digit version:

Pascal's Pascaline [photo © 2002 IEEE]

A 6 digit model for those who couldn't afford the 8 digit model

A Pascaline opened up so you can observe the gears and cylinders which rotated to display the numerical result
Click on the "Next" hyperlink below to read about the punched card system that was developed for looms for later applied to the U.S. census and then to computers...