AN OVERVIEW ON KEYBOARD AND MOUSE

AN OVERVIEW:
 THE KEYBOARD ANDTHE MOUSE( INPUT DEVICE)
If the CPU is the computer’s brain, then the input
devices are its eyes and ears. From the user’s point of
view, input devices are just as important as the CPU-
more so, in fact. An input device does exactly what
its name suggests: it enables you to input
information and commands into the computer.
The most commonly used input devices are the
keyboard and the mouse.
The discussion about keyboard and mouse are
given below.

The keyboard was one of the first peripherals to be used
with computers, and it is still the primary input device for
entering text and numbers. A standard keyboard includes
about 100 keys: each key sends a different signal to the CPU.
we can say that a keyboard is a typewriter like device
which uses an arrangement of buttons or keys, to act as a
mechanical levers or electronic switchs.

HISTORY OF KEYBOARD:
Earliest keyboard

KEYS TYPE
 A typical computer keyboard comprises sections with different
types of keys.
 A computer keyboard comprises alphanumeric or character
keys for typing, modifier keys for altering the functions of other
keys, navigation keys for moving the text cursor on the screen,
function keys and system command keys – such as Esc and
Break – for special actions, and often a numeric keypad to
facilitate calculations.
 Character keys
The core section of a keyboard comprises character keys,
which can be used to type letters and other characters.
Typically, there are three rows of keys for typing letters and
punctuation, an upper row for typing digits and special
symbols, and the Spacebar on the bottom row. The positioning
of the character keys is similar to the keyboard of a typewriter.

 Modifier keys
Besides the character keys, a keyboard incorporates special keys that do
nothing by themselves but modify the functions of other keys. For
example, the ⇧ Shift key can be used to alter the output of character
keys, whereas the Ctrl (control) and Alt (alternate) keys trigger special
operations when used in concert with other keys.
 Dead keys
A dead key is a special kind of a modifier key that, instead of being
held while another key is struck, is pressed and released before the other
key. The dead key does not generate a character by itself, but it modifies
the character generated by the key struck immediately after, typically
making it possible to type a letter with a specific diacritic. For example,
on some keyboard layouts, the grave accent key ` is a dead key; in this
case, striking ` and then A results in à (a with grave accent), whereas `
followed by E results in è (e with grave accent). A grave accent in isolated
form can be typed by striking ` and then Space bar.

 Compose key
A Compose key can be characterized as a generic dead key
that may in some systems be available instead of or in
addition to the more specific dead keys. It allows access to a
wide range of predefined extra characters by interpreting a
whole sequence of keystrokes following it. For example,
striking Compose followed by ' (apostrophe) and then A
results in á (a with acute accent), Compose followed by A
and then E results in æ (ae ligature), and Compose followed
by O and then C results in © (circled c, copyright symbol).
The Compose key is supported by the X Window System
(used by most Unix-like operating systems, including most
GNU/Linux distributions). Some keyboards have a key
labelled “Compose”, but any key can be configured to serve
this function. For example, the otherwise redundant right-
hand ⊞ Win key may, when available, be used for this
purpose.

A normal computer keyboard is composed of around
110 keys. Although on the basis of key arrangements
there are four major layouts being used worldwide,
QWERTY, AZERTY, QWERTZ and HCESAR, but they
can be classified in many more different categories
depending on types of computer connector, size,
number of keys etc. Among the various types listed
below, keyboards can be based on multiple types. For
instance, an ergonomic keyboard can have a PS2
interface and be an internet keyboard too.

 ERGONOMIC KEYBOARD
The artifact of this keyboard is slightly broader and
different in shape, when compared with the normal
keyboard. In this key board certain space will be existing
between the two sets of keys and the countered shape of
this key board allow the users to place their hands in the
natural position to type. These key boards are mostly used
by the people who often work with the key board as their
usage is easier and is less stressful for the wrist. The
following figure: Ergonomic keyboard shows how the set of
keys are separated with gaps in between.

 ADB (Apple Desktop Bus)
ADB refers to a special type of port which is
enabled in some computers such as Apple
computers. The ADB key boards can be
connected only to the ADB jack enabled
computers, but with the use of the adapter,
the ADB key boards can also be inserted over
a USB port.
ADB connected keyboard

 XT KEYBOARD:
An obsolete type, these keyboards only support the
older computers such as IBM 8086/8088, XT-286. Not
supported by present computers, keyboards are much
larger than the modern keyboards and the “Enter” key is
backward-”L” shaped.
 PERSONAL SYSTEMS (PS/2) CONNECTED KEYBOARD:
In the late 1990, most of the computers are integrated
with standard PS/2 connector, rather than USB ports, there
by the keyboards used for these computers are usually
round pin that fits into the PS/2 keyboard jack. For this
reason these keyboards are named as PS/2 keyboards.
Xt keyboard
PS/2 connector

 MULTIMEDIA KEYBOARD:
The multimedia keyboard is specially designed for the people who
are much into multimedia designing. This keyboard is just like the
standard key board, but composed of additional keys for the
multimedia purposes such as multimedia application launch,
volume control and mute button.
 INTERNET KEYBOARD:
The Internet keyboards are designed for wider range of
multimedia applications, these keyboards are specially designed for
the intense Internet user. The special keys included in this keyboard
are the home key, back and forward key, e-mail launch key, and
browser launch key etc. these keys carry out the same functionality
as of the buttons on the webpage. In order use these extra keys the
computer must be embedded with right operating system.
Multimedia keyboard
Internet keyboard

 WIRELESS KEYBOARD:
A wireless keyboard, the name itself doles the meaning that this keyboard can
be operated without addressing a wired connection to the processor. The wireless
keyboards are also referred as Cordless keyboards; these keyboards require batteries
to provide the electricity which usually delivered through a PS/2 or USB cable. “AA”
or “AAA” batteries are most widely used standard batteries for wireless
keyboards. Apple Macs are known to revolutionize the wireless keyboard by making
them thinner than the wired ones. These keyboards usually work at 2.4 GHz
frequency and come with a dongle that connects and makes them communicate with
the computer.
 GAMING KEYBOARD:
As the name suggest, gaming keyboards are those who are into gaming and need
easy access to the keys that are usually utilized in gaming. These keyboards are
composed of particular gaming-oriented features such as key lighting,
programmable keys, and/or extra controls of volume and brightness. These
keyboards are available in wired and wireless, in case if wired, it usually supports the
USB port.
Gaming keyboardWireless keyboard

 MEMBRANE KEYBOARD:
Membrane keyboards are one of the
keyboard types, which are used very rarely.
The keys integrated in this keyboard are non-
moving pressure-sensitive keys. The keys in
this keyboard are so close, so that there is no
scope for spilling liquids into the
keyboard. Such keyboard types are also
used in mobile phones and old landline
phones.

 Laser computer keyboard
The future of computer keyboard is laser computer keyboard. I didn’t find out its brand
and manufacturers; let’s just call it Bluetooth laser keyboard. It’s another laser computer
keyboard, and its dimensions approximately are 35*92*25 mm. It’s connected by Bluetooth
v1.1 class 2. It has a Project 295*95 mm virtual keyboard with full size and QWERT layout.
 Roll Up QWERTY Keyboard
It is a flexible and virtually indestructible QWERTY keyboard. The moisture-resistant
silicone allows to spill as much as you like with no effect on function. Dropping donut
crumbs into more traditional keyboards requires tediously removing keys to clean out the
mess. The bendable silicon allows for easy transportation and the material creates a
soundless typing experience. It is perfect for industrial or wet areas such as factories, labs,
workshops, restaurants, shops and food preparation areas. As it rolls up into a compact
bundle, it's also ideal for travelers. It can even be used in sandstorms.
Laser keyboard
Roll up keyboard

 Dome-switch keyboard
Dome-switch keyboards are a hybrid of flat-panel membrane and mechanical
keyboards. They bring two circuit board traces together under a rubber or silicone
keypad using either metal "dome" switches or polyester formed domes. The metal
domes switches are formed pieces of stainless steel that, when compressed, give
the user a crisp, positive tactile feedback. These metal types of dome switches are
very common, are usually reliable to over 5 million cycles, and can be plated in
nickel, silver or gold. The rubber dome switches, most commonly referred to as
polydomes, are formed polyester domes where the inside bubble is coated in
graphite. While polydomes are typically cheaper than metal domes, they lack the
crisp snap of the metal domes, and usually have a lower life specification.
Polydomes are considered very quiet, but purists tend to find them "mushy"
because the collapsing dome does not provide as much positive response as metal
domes. For either metal or polydomes, when a key is pressed, it collapses the
dome, which connects the two circuit traces and completes the connection to enter
the character. The pattern on the PC board is often gold-plated.
Dome switch keyboard

 Scissor-switch keyboard
A special case of the computer keyboard dome-switch is the scissor-
switch. The keys are attached to the keyboard via two plastic pieces that
interlock in a "scissor"-like fashion, and snap to the keyboard and the key. It
still uses rubber domes, but a special plastic 'scissors' mechanism links the
keycap to a plunger that depresses the rubber dome with a much shorter
travel than the typical rubber dome keyboard. Typically scissor-switch
keyboards also employ 3-layer membranes as the electrical component of the
switch. They also usually have a shorter total key travel distance (2 mm
instead of 3.5 – 4 mm for standard dome-switch key switches). This type of
key switch is often found on the built-in keyboards on laptops and keyboards
marketed as 'low-profile'. These keyboards are generally quiet and the keys
require little force to press.
Scessor switch keyboard Switch as like a scissor

 Buckling-spring keyboard
Many typists prefer buckling spring keyboards. The buckling spring mechanism
(expired U.S. Patent 4,118,611) atop the switch is responsible for the tactile and aural
response of the keyboard. This mechanism controls a small hammer that strikes a
capacitive or membrane switch. In 1993, two years after spawning Lexmark, IBM
transferred its keyboard operations to the daughter company. New Model M keyboards
continued to be manufactured for IBM by Lexmark until 1996, when Unicomp
purchased the keyboard technology. Today, new buckling-spring keyboards are
manufactured by Unicomp. Unicomp also repairs old IBM and Lexmark keyboards.
 Hall-effect keyboard
Hall effect keyboards use magnets and Hall effect sensors instead of an actual switch.
When a key is pressed, it moves a magnet, which is detected by the solid-state sensor.
These keyboards are extremely reliable, and are able to accept millions of keystrokes
before failing. They are used for ultra-high reliability applications, in locations like
nuclear powerplants or aircraft cockpits. They are also sometimes used in industrial
environments. These keyboards can be easily made totally waterproof. They also resist
large amounts of dust and contaminants. Because a magnet and sensor is required for
each key, as well as custom control electronics, they are very expensive.
Buckling-spring keyboard
Hall effect keyboard

 Thumb-sized keyboard:
Smaller external keyboards have been introduced for devices without a built-in
keyboard, such as PDAs, and smart phones. Small keyboards are also useful where there is
a limited workspace. A chorded keyboard allows pressing several keys simultaneously. For
example, the GKOS keyboard has been designed for small wireless devices. Other two-
handed alternatives more akin to a game controller, such as the Alpha Grip, are also used
as a way to input data and text. A thumb keyboard (thumb board) is used in some
personal digital assistants such as the Palm Treo and BlackBerry and some Ultra-Mobile PCs
such as the OQO.
 Numeric keyboard:
Numeric keyboards contain only numbers, mathematical symbols for addition,
subtraction, multiplication, and division, a decimal point, and several function keys. They
are often used to facilitate data entry with smaller keyboards that do not have a numeric
keypad, commonly those of laptop computers. These keys are collectively known as a
numeric pad, numeric keys, or a numeric keypad, and it can consist of the following types
of keys:
1.arithmetic operators such as +, -, *, /
2.numeric digits 0–9
3.cursor arrow keys
4.Navigation keys such as Home, End, Page Up, Page Down, etc.
5.Num Lock button, used to enable or disable the numeric pad
6.enter key
Thumb sized keyboard Numerc keyboard

• CHORDED KEYBOARD:
While other keyboards generally associate one action with each key,
chorded keyboards associate actions with combinations of key presses.
Since there are many combinations available, chorded keyboards can
effectively produce more actions on a board with fewer keys. Court
reporters' stenotype machines use chorded keyboards to enable them to
enter text much faster by typing a syllable with each stroke instead of one
letter at a time. The fastest typists (as of 2007) use a stenograph, a kind of
chorded keyboard used by most court reporters and closed-caption
reporters. Some chorded keyboards are also made for use in situations
where fewer keys are preferable, such as on devices that can be used with
only one hand, and on small mobile devices that don't have room for
larger keyboards. Chorded keyboards are less desirable in many cases
because it usually takes practice and memorization of the combinations to
become proficient.
Chorded keyboard

THE INTERNAL CIRCUIT OF A
KEYBOARD:
 Internal Keyboard Circuitry
The "brain" of the keyboard is the circuitry within the unit that handles the processing of keystrokes and exchanging
information with the host system (the rest of the PC). While keyboards are fairly simple devices, you might be surprised at
just how complex the internal circuitry is in a keyboard. In some ways it's like another whole computer in there...
In fact, the keyboard has within it small versions of several components you find within the PC as a whole. It has its own
microprocessor, which "runs the show" so to speak. (This is of course a tiny CPU like the 8048, not a full-fledged CPU as the
main PC hardware uses.) There is also some read-only memory (ROM) that runs this small processor, similar to the system
BIOS code on the motherboard. Programmable keyboards also contain some EEPROM memory to hold programming
information; this functions as if it were a tiny hard disk, in a way. Sort of. ;^)
This internal circuitry has two fundamental jobs. First, it is responsible for sensing the raw signals created by the
keyswitches as they make electrical contact, and translating them into signals that can be sent to the PC. Due to the electrical
characteristics of keystrokes, this is not as simple as it sounds. Second, it handles the actual interfacing between the keyboard
and the rest of the PC system. The interface between the PC and the keyboard is a full bi-directional serial communications
line, with its own special protocols and commands.

MOUSE
Mouse is a device that controls the movement of the cursor
or pointer on a display screen. A mouse is a small object you
can roll along a hard, flat surface. Its name is derived from its
shape, which looks a bit like a mouse, its connecting wire that
one can imagine to be the mouse's tail, and the fact that one
must make it scurry along a surface. As you move the mouse,
the pointer on the display screen moves in the same direction.
Mice contain at least one button and sometimes as many as
three, which have different functions depending on what
program is running. Some newer mice also include a scroll
wheel for scrolling through long documents.

For most of their history, computers were the province of scientists and
mathematicians. You needed a math degree just to understand the manual
and you could only tell them what to do by feeding in a stack of index cards
punched with holes. All that started to change when a brilliant US computer
scientist namedDouglas Engelbart (1925–) invented the computer mouse.
Engelbart realized computers were far too useful just for boffins: he
could see they had the power to change people's lives. But he could also see
that they needed to be much easier to use. So, during the 1960s, he
pioneered most of the easy-to-use computer technologies that we now take
for granted, including on-screen word processing, hypertext (the way of
linking documents together used in web pages like these), windows (so you
can have more than one document or program in view at a time), and video
conferencing.
But he's still best known for inventing the mouse, or the "X-Y Position
Indicator" as it was originally known. That stuffy name was dropped when
someone spotted that the cable hanging out looked just like a mouse's tail.
From then on, Engelbart's invention was known simply as the "mouse".
Early mouse patent. The first computer mouse

TYPES OF MOUSE:
 There are three basic types of mice:
1.Mechanical: Has a rubber or metal ball on its
underside that can roll in all directions. Mechanical
sensors within the mouse detect the direction the ball is
rolling and move the screen pointer accordingly.
2.Optomechanical: Same as a mechanical mouse,
but uses optical sensors to detect motion of the ball.
3.Optical: Uses a laser to detect the mouse's
movement. You must move the mouse along a special
mat with a grid so that the optical mechanism has a frame
of reference. Optical mice have no mechanical moving
parts. They respond more quickly and precisely than
mechanical and optomechanical mice, but they are also
more expensive.

OPTO-MECHANICAL MOUSE
 Opto-Mechanical mouse: Houses a hard rubber ball
that rolls as the mouse is moved. Sensors inside the
mouse body detect the movement and translate it into
information that the computer interprets.
This is the internal view of a opto-mechanical mouseOpto-mechnical mouse

 Operating an opto-mechanical mouse.
1.moving the mouse turns the ball.
2.X and Y rollers grip the ball and transfer
movement
3.Optical encoding disks include light holes.
4.Infrared LEDs shine through the disks.
5.Sensors gather light pulses to convert to X and Y
vectors

OPTICAL MOUSE
Optical mouse: Uses a laser to detect the mouse's
movement. You must move the mouse along a special mat
with a grid so that the optical mechanism has a frame of
reference. Opticalmice have no mechanical moving parts.
They respond more quickly and precisely than mechanical
and optomechanical mice, but they are also more
expensive.
Optical mouse

WORKING PRINCIPLE:
Optical mice make use of one or more light-emitting
diodes (LEDs) and an imaging array of photodiodes to
detect movement relative to the underlying surface, rather
than internal moving parts as does a mechanical mouse. A
laser mouse is an optical mouse that uses coherent (laser)
light.
The earliest optical mice detected movement on pre-
printed mousepad surfaces, whereas the modern optical
mouse works on most opaque surfaces; it is unable to
detect movement on specular surfaces like glass. Laser
diodes are also used for better resolution and precision.
Battery powered, wireless optical mice flash the LED
intermittently to save power, and only glow steadily when
movement is detected.

1. Inertial and gyroscopic mice
2. 3D mice
3. Tactile mice
4. Ergonomic mice
5. Gaming mice
6. Trackball mice
7. Stylus mice
8. Chordless 3D mice
9. Foot mice
10. Rotational mice
11. LED mice
12. LASER mice

INERTIAL AND GYROSCOPIC MICE
Often called "air mice" since they do not require a surface to operate,
inertial mice use a tuning fork or other accelerometer (US Patent 4787051)
to detect rotary movement for every axis supported. The most common
models (manufactured by Logitech and Gyration) work using 2 degrees of
rotational freedom and are insensitive to spatial translation. The user
requires only small wrist rotations to move the cursor, reducing user
fatigue or "gorilla arm".
Usually cordless, they often have a switch to deactivate the movement
circuitry between use, allowing the user freedom of movement without
affecting the cursor position. A patent for an inertial mouse claims that such
mice consume less power than optically based mice, and offer increased
sensitivity, reduced weight and increased ease-of-use. In combination with
a wireless keyboard an inertial mouse can offer alternative ergonomic
arrangements which do not require a flat work surface, potentially
alleviating some types of repetitive motion injuries related to workstation
posture.
Inertial mouse

3D MICE
Also known as bats, flying mice, or wands, these devices generally
function through ultrasound and provide at least three degrees of
freedom. Probably the best known example would
be 3Dconnexion/Logitech's SpaceMouse from the early 1990s. In the
late 1990s Kantek introduced the 3D RingMouse. This wireless mouse
was worn on a ring around a finger, which enabled the thumb to access
three buttons. The mouse was tracked in three dimensions by a base
station. Despite a certain appeal, it was finally discontinued because it
did not provide sufficient resolution.
A recent consumer 3D pointing device is the Wii Remote. While
primarily a motion-sensing device (that is, it can determine its
orientation and direction of movement), Wii Remote can also detect its
spatial position by comparing the distance and position of the lights
from the IR emitter using its integrated IR camera (since
the nunchuk accessory lacks a camera, it can only tell its current
heading and orientation). The obvious drawback to this approach is that
it can only produce spatial coordinates while its camera can see the
sensor bar.
3D mice

TACTILE MICE
In 2000, Logitech introduced the "tactile mouse",
which contained a small actuator that made the mouse
vibrate. Such a mouse can augment user-interfaces
with haptic feedback, such as giving feedback when
crossing a window boundary. To surf by touch requires
the user to be able to feel depth or hardness; this
ability was realized with the first electrorheological
tactile mice but never marketed.
Tactile mouse

ERGONOMIC MICE
As the name suggests, this type of mouse is
intended to provide optimum comfort and
avoid injuries such as carpal tunnel
syndrome, arthritis and other repetitive strain
injuries. It is designed to fit natural hand
position and movements, to reduce discomfort.
Ergonomic mouse

These mice are specifically designed for use
in computer games. They typically employ a wide
array of controls and buttons and have designs that
differ radically from traditional mice. It is also
common for gaming mice, especially those designed
for use in first-person shooter games, to have a
relatively high sensitivity, measured in dots per inch
(DPI). Ergonomic quality is also an important factor in
gaming mice, as extended gameplay times may
render further use of the mouse to be uncomfortable.
Gaming mouse

Trackball mouse:
Like an upside-down mouse. Rather
than roll the mouse around, you use your
thumb or index finger to roll a ball on top of
the mouse. The whole contraption stays
stationary, so it doesn’t need a lot of room,
and its cord never gets tangled.

 Stylus mouse: Another mouse mutation
enjoyed by the artistic type is the stylus
mouse, which looks like a pen and draws on
a special pad.
 Cordless 3-D mouse: This kind of mouse
can be pointed at the computer screen like
aTV remote.

A footmouse is a type of computer mouse that
gives the users the ability to move the cursor and
click the mouse buttons with their feet. It is
primarily used by users with disabilities or with
high-back or neck problems. It is also promoted as a
way to prevent such problems in the future and as a
means to increase productivity by not having to
move one's hand between the keyboard and mouse
Footmouse that tilts and rotates.
Footmouse that slides in four directions.

ROTATIONAL MIUSE
A rotational mouse is a type of computer
mouse which attempts to expand traditional
mouse functionality. The objective of rotational
mice is to facilitate three degrees of freedom
(3DOF) for human-computer interaction by
adding a third dimensional input, yaw, to the
existing x and y dimensional inputs. There have
been several attempts to develop rotating mice,
using a variety of mechanisms to detect rotation.
Rotational mice

LED MICE
Optical mice often use LEDs for
illumination, even though they are sometimes
colloquially referred to as 'lasers'. The color of
the optical mouse's light-emitting diodes can
vary, but red is most common, as red diodes
are inexpensive and silicon photodetectors
are very sensitive to red light. Other colors
are sometimes used, such as the blue LED of
the V-Mouse VM-101 illustrated at right.
Led mouse

LASER MICE
The laser mouse uses an infrared laser diode instead of a
LED to illuminate the surface beneath their sensor. As early as
1998, Sun Microsystems provided a laser mouse with their Sun
SPARCstation servers and workstations. However, laser mice did
not enter the mainstream market until 2004, when Paul Machin
at Logitech, in partnership with Agilent Technologies, introduced
its MX 1000 laser mouse. This mouse uses a small infrared laser
instead of a LED and has significantly increased the resolution of
the image taken by the mouse. The laser enables around 20
times more surface tracking power to the surface features used
for navigation compared to conventional optical mice.
Laser mouse

CONNECTIVITY AND COMMUNICATION PROTOCOLS
To transmit their input, typical cabled mice use a thin electrical cord
terminating in a standard connector, such as RS-232C, PS/2,ADB or USB.
Cordless mice instead transmit data via infrared radiation (see IrDA)
or radio (including Bluetooth), although many such cordless interfaces are
themselves connected through the aforementioned wired serial buses.
While the electrical interface and the format of the data transmitted by
commonly available mice is currently standardized on USB, in the past it
varied between different manufacturers. A bus mouse used a dedicated
interface card for connection to an IBM PC or compatible computer.
Mouse use in DOS applications became more common after the
introduction of the Microsoft mouse, largely because Microsoft provided an
open standard for communication between applications and mouse driver
software. Thus, any application written to use the Microsoft standard could
use a mouse with a Microsoft compatible driver (even if the mouse hardware
itself was incompatible with Microsoft's). An interesting footnote is that the
Microsoft driver standard communicates mouse movements in standard units
called "mickeys", as does the Allegro library.

Standard PC mice once used the RS-232C serial
port via a D-subminiature connector, which
provided power to run the mouse's circuits as well
as data on mouse movements. The Mouse Systems
Corporation version used a five-byte protocol and
supported three buttons. The Microsoft version used
a three-byte protocol and supported two buttons.
Due to the incompatibility between the two
protocols, some manufacturers sold serial mice with
a mode switch: "PC" for MSC mode, "MS" for
Microsoft mode.

 With the arrival of the IBM PS/2 personal-computer
series in 1987, IBM introduced the eponymous PS/2
interface for mice and keyboards, which other
manufacturers rapidly adopted. The most visible change
was the use of a round 6-pin mini-DIN, in lieu of the
former 5-pin connector. In default mode (called stream
mode) a PS/2 mouse communicates motion, and the
state of each button, by means of 3-byte packets. For any
motion, button press or button release event, a PS/2
mouse sends, over a bi-directional serial port, a
sequence of three bytes, with the following format:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Byte 1 YV XV YS XS 1 MB RB LB
Byte 2 X movement
Byte 3 Y movement

APPLE DESKTOP BUS
In 1986 Apple first implemented the Apple Desktop
Bus allowing the daisy-chaining together of up to 16
devices, including arbitrarily many mice and other devices
on the same bus with no configuration whatsoever.
Featuring only a single data pin, the bus used a purely
polled approach to computer/mouse communications and
survived as the standard on mainstream models
(including a number of non-Apple workstations) until 1998
when iMac joined the industry-wide switch to using USB.
Beginning with the "Bronze Keyboard" PowerBook G3 in
May 1999, Apple dropped the external ADB port in favor
of USB, but retained an internal ADB connection in
thePowerBook G4 for communication with its built-in
keyboard and trackpad until early 2005.

 The industry-standard USB (Universal Serial Bus)
protocol and its connector have become widely used for
mice; it is among the most popular types.
 Cordless or wireless mice transmit data via infrared
radiation or radio. The receiver is connected to the
computer through a serial or USB port, or can be built in
(as is sometimes the case with Bluetooth). Modern non-
Bluetooth wireless mice use USB receivers. Some of
these can be stored inside the mouse for safe transport
while not in use, while other, newer mice use newer
"nano" receivers, designed to be small enough to remain
plugged into a laptop during transport, while still being
large enough to easily remove.

ATARI STANDARD JOYSTICK CONNECTIVITY
 The Amiga and the Atari ST use an Atari standard DE-
9 connector for mice, the same connector that is used
for joysticks on the same computers and numerous 8-
bit systems, such as the Commodore 64 and the Atari
2600. However, the signals used for mice are different
from those used for joysticks. As a result, plugging a
mouse into a joystick port causes the "joystick" to
continuously move in some direction, even if the
mouse stays still, whereas plugging a joystick into a
mouse port causes the "mouse" to only be able to move
a single pixel in each direction.

 Here's the inside of an old-style Logitech ball mouse:
1.Switch detects clicks of left mouse button.
2.Switch for middle button.
3.Switch for right button.
4.Old-style connection to PS/2 socket on
computer.
5.Chip turns back-and-forth (analog) mouse
movements into numeric (digital) signals
computer can understand.
6.X-axis wheel turns when you move mouse left and right.
7.Y-axis wheel turns when you move mouse up and down.
8.Heavy rubber wheel.
9.Spring presses rubber ball firmly against X- and Y-axis wheels so they register
movements properly.
10Electrolytic capacitor.
11Resistors.

How a ball computer mouse
works.
 As you move it across your desk, the ball
rolls under its own weight and pushes
against two plastic rollers linked to thin
wheels (numbered 6 and 7 in the photo).
One of the wheels detects movements in an
up-and-down direction (like the y-axis on
graph/chart paper); the other detects side-
to-side movements (like the x-axis on graph
paper).

1.An LED at the back generates red light
and shines it horizontally, from the back
of the mouse toward the front (from the left
to the right of this photo).
2.A plastic prism bends (refracts) the light
from the LED at an angle, down onto the
desk.
3.A light-detector chip measures light
reflected back up from the desk, converting the analog movements of your
hand into digital signals that can be sent to your computer.
4.The scroll wheel at the front of the mouse is mounted on a switch
mechanism that detects both how much it's rotated and whether you've
pressed it (it functions like the central button of a conventional mouse).
Rotations of the scroll wheel can be detected in a variety of different ways.
Some mice use potentiometers (broadly, variable resistors), similar to the
volume control on a radio but able to turn around multiple times. Others
use various kinds of rotary switches or optical (rotary) encoders to
convertanalog wheel movements to digital signals.
5.A microswitch detects when you press the right mouse button. There's an
identical switch on the other side to detect the left mouse button.
6.The USB cable connection carries digital information from the mouse to your
computer.

 An optical mouse works in a completely
different way. It shines a bright light
down onto your desk from anLED
(light-emitting diode) mounted on the bottom of the mouse.
The light bounces straight back up off the desk into
a photocell (photoelectric cell), also mounted under the
mouse, a short distance from the LED. The photocell has
a lens in front of it that magnifies the reflected light, so the
mouse can respond more precisely to your hand movements. As
you push the mouse around your desk, the pattern of reflected
light changes, and the chip inside the mouse uses this to figure
out how you're moving your hand.
Some optical mice have two LEDs. The first one shines light
down onto the desk. The light from that is picked up by the
photocell. The second LED lights up a red plastic strip along
the back of the mouse so you can see it's working. Most optical
mice also have a wheel at the front so you can scroll pages on-
screen much faster. You can click the wheel too, so it functions
like the third (center) button on a conventional ball mouse.

Some systems allow two or more mice to be used at
once as input devices. 16-bit era home computers such
as the Amiga used this to allow computer games with
two players interacting on the same computer. The
same idea is sometimes used in collaborative software,
e.g. to simulate a whiteboard that multiple users can
draw on without passing a single mouse around.
Microsoft Windows, since Windows 3.1, has supported
multiple simultaneous pointing devices. Because
Windows only provides a single screen cursor, using
more than one device at the same time requires
cooperation of users or applications designed for
multiple input devices.
Multiple mice are often used in multi-user gaming in
addition to specially designed devices that provide
several input interfaces.
Windows also has full support for multiple
input/mouse configurations for multiuser environments.

Mouse buttons are microswitches which can
be pressed to select or interact with an element
of a graphical user interface, producing a
distinctive clicking sound.
The three-button scrollmouse has become the
most commonly available design. As of 2007 (and
roughly since the late 1990s), users most
commonly employ the second button to invoke
a contextual menu in the computer's software
user interface, which contains options
specifically tailored to the interface element
over which the mouse cursor currently sits. By
default, the primary mouse button sits located
on the left-hand side of the mouse, for the
benefit of right-handed users; left-handed users
can usually reverse this configuration via
software.

Mickey is the unit of measurement for the speed and
movement direction of a computer mouse. The speed of
the mouse is the ratio between how many pixels the cursor
moves on the screen and how many centimeters you move
the mouse on the mouse pad. The directional movement is
called the horizontal mickey count and the vertical mickey
count. One mickey is approximately 1/200th of an inch.
The computer industry often measures mouse sensitivity
in terms of counts per inch (CPI), commonly expressed as
dots per inch (DPI) – the number of steps the mouse will
report when it moves one inch. In early mice, this
specification was called pulses per inch (ppi).
If the default mouse-tracking condition involves moving
the cursor by one screen-pixel or dot on-screen per
reported step, then the CPI does equate to DPI: dots of
cursor motion per inch of mouse motion.

The CPI or DPI as reported by manufacturers depends on how they
make the mouse; the higher the CPI, the faster the cursor moves with
mouse movement. However, software can adjust the mouse sensitivity,
making the cursor move faster or slower than its CPI. Current software
can change the speed of the cursor dynamically, taking into account the
mouse's absolute speed and the movement from the last stop-point. In
most software this setting is named "speed", referring to "cursor
precision". However, some software names this setting "acceleration",
but this term is in fact incorrect. The mouse acceleration, in the majority
of mouse software, refers to the setting allowing the user to modify the
cursor acceleration: the change in speed of the cursor over time while
the mouse movement is constant.
For simple software, when the mouse starts to move, the software will
count the number of "counts" or "mickeys" received from the mouse and
will move the cursor across the screen by that number of pixels (or
multiplied by a rate factor, typically less than 1). The cursor will move
slowly on the screen, having a good precision. When the movement of
the mouse passes the value set for "threshold", the software will start to
move the cursor more quickly, with a greater rate factor. Usually, the user
can set the value of the second rate factor by changing the "acceleration"
setting.

Operating systems sometimes apply acceleration,
referred to as "ballistics", to the motion reported by the
mouse. For example, versions of Windows prior
to Windows XP doubled reported values above a
configurable threshold, and then optionally doubled them
again above a second configurable threshold. These
doublings applied separately in the X and Y directions,
resulting in very nonlinear response

Mousepads
Engelbart's original mouse did not require a
mousepad; the mouse had two large wheels which could
roll on virtually any surface. However, most subsequent
mechanical mice starting with the steel roller ball mouse
have required a mousepad for optimal performance.
The mousepad, the most common mouse accessory,
appears most commonly in conjunction with mechanical
mice, because to roll smoothly the ball requires more
friction than common desk surfaces usually provide. So-
called "hard mousepads" for gamers or optical/laser
mice also exist.
Most optical and laser mice do not require a pad.
Whether to use a hard or soft mousepad with an optical
mouse is largely a matter of personal preference. One
exception occurs when the desk surface creates
problems for the optical or laser tracking, for example, a
transparent or reflective surface.

SOME UNUSUAL MICE
Gold brain computer mouse
Aircraft computer mouse with led lights
Wireless mouse – camaro black
The man’s body mouse

Optical ferrari car mouse
Cyborg r.a.t. gaming mice
Optical mouse skype hands-free pc speakerphone

Eclipse touchmouse
portable finger hand held 4d usb mini trackball mouse
Golf 3d usb optical computer mouse

Wowpen joy vertical computer mouse Creative golf mouse
Handshoe mouse

Another keypad mouse
Hybrid monster naga mouse
Body mouse

Crystal computer mouse
Tortoise-shaped optical usb mouse
A steampunk mouse

AN OVERVIEW ON KEYBOARD AND MOUSE

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