MOUSE

What is a mouse?

A mouse is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons.

The mouse sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features that can add more control or dimensional input. The mouse's motion typically translates into the motion of a pointer on a display, which allows for fine control of a graphical user interface.

There are different types of mouse. They are:

1)      Two button mouse

2)      3 button mouse

        The middle button is very rarely. These mouses are useful for 3d designing softwares like MAYA etc..

3)      Scroll mouse

4)      Optical mouse

The first three types of mouse are ball mouse and the scroll mice are available even in optical mouse.

The working of ball mouse is:

These are also called mechanical mouse. The ball mouse has two freely rotating rollers. They are located 90 degrees apart. One roller detects the forward–backward motion of the mouse and other the left–right motion. Opposite the two rollers is a third one (white, in the photo, at 45 degrees) that is spring-loaded to push the ball against the other two rollers. Each roller is on the same shaft as an encoder wheel that has slotted edges; the slots interrupt infrared light beams to generate electrical pulses that represent wheel movement. Each wheel's disc, however, has a pair of light beams, located so that a given beam becomes interrupted, or again starts to pass light freely, when the other beam of the pair is about halfway between changes. Simple logic circuits interpret the relative timing to indicate which direction the wheel is rotating. This scheme is sometimes called quadrature encoding of the wheel rotation, as the two optical sensor produce signals that are in approximately quadrature phase. The mouse sends these signals to the computer system via the mouse cable, directly as logic signals in very old mice such as the Xerox mice, and via a data-formatting IC in modern mice. The driver software in the system converts the signals into motion of the mouse cursor along X and Y axes on the computer screen.

The ball is mostly steel, with a precision spherical rubber surface. The weight of the ball, given an appropriate working surface under the mouse, provides a reliable grip so the mouse's movement is transmitted accurately.

The working of optical mouse:

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. LED-based optical mice are fairly recent, another type of optical mouse has been around for over a decade. The original optical-mouse technology bounced a focused beam of light off a highly-reflective mouse pad onto a sensor. The mouse pad had a grid of dark lines. Each time the mouse was moved, the beam of light was interrupted by the grid. Whenever the light was interrupted, the sensor sent a signal to the computer and the cursor moved a corresponding amount. This kind of optical mouse was difficult to use, requiring that you hold it at precisely the right angle to ensure that the light beam and sensor aligned. Also, damage to or loss of the mouse pad rendered the mouse useless until a replacement pad was purchased. Today's LED-based optical mice are far more user-friendly and reliable.

The buttons and scroll on the mouse are the only ways of input through the pointer device. The left button is used for the selection purpose and the right button is used to open the menu options of the relative window or the file we are trying to access. The scroll option is used to move a page up and down or to zoom in or zoom out images. If required we can change the input properties of the buttons from the function of left button to right and vice versa.

Connectors:

The mouse  has 4 wires each wire of different color:-

1)      White - ground connection

2)      Green – clock settings

3)      Red – power

4)      Yellow – data transfer

Connectors:

1)      Serial connector

2)      Ps/2 connector

3)      USB connectors

Serial connectors:

These connectors were used in previous days. These were used in P1, P2, P3 mother boards. It is a big size connector with 9 bold pins arranged in 2 rows in it.

PS/2 connectors:

These pins are used in the P3, previous generations of P4 mother boards and are used even nowadays. It is a mini size DIN connector with six delicates pins in it.

USB connectors:

These are universal serial bus connectors these are used in the latest computers these are rectangular shaped connectors with golden strips in them.