Mouse

Mouse

Introduction of a mouse

Mice first broke onto the public stage with the introduction of the Apple Macintosh in 1984, and since then they have helped to completely redefine the way we use computers

The modern windows – based PC needs a pointing device to position the cursor on the screen and to issue commands. There are several possibilities, but by far the most common is a mouse

MICE

Ø Contains a micro controller and firmware
Ø The ‘Rolls Royce’ of mice is the optical mouse
Ø The most common is the opt-electronic
Ø It is used with GUI system to give graphical inputs.
Ø It is cheap and easy to use.
Ø It is a high precision input device

Type of Mouse

Scroll Mouse

Track ball mouse

Optical mouse

Wireless Ergonomic finger trackball mouse

Basic Mouse Operation

Ø As you move the mouse on a flat surface the ball turns the rollers inside and sends signals to the computer, the computer then translates these signals into the movement of the mouse pointer.

Ø When the disk rotates, it alternatively closes and opens a photo sensor assembly. The number of interruptions the sensor senses, gives the amount of mouse’s movement in X and Y direction

Ø The mouse has two or three buttons, which are used for various purposes.

How Computer Mouse Work
Inside a Mouse

· The main goal of any mouse is to translate the motion of your hand into signals that the computer can use. Almost all mice today do the translation using five components:

· A ball inside the mouse touches the desktop and rolls when the mouse moves*he underside of the mouse's logic board: The exposed portion of the ball touches the desktop

Two rollers inside the mouse touch the ball. One of the rollers is oriented so that it detects motion in the X direction, and the other is oriented 90 degrees to the first roller so it detects motion in the Y direction. When the ball rotates, one or both of these rollers rotate as well. The following image shows the two white rollers on this mouse:

The rollers that touch the ball and detect X and Y motion

The rollers each connect to a shaft, and the shaft spins a disk with holes in it. When a roller rolls, its shaft and disk spin. The following image shows the disk:

A typical optical encoding disk: This disk has 36 holes around its outer edge.

On either side of the disk there is an infrared LED and an infrared sensor. The holes in the disk break the beam of light coming from the LED so that the infrared sensor sees pulses of light. The rate of the pulsing is directly related to the speed of the mouse and the distance it travels

A close-up of one of the optical encoders that track mouse motion: There is an infrared LED (clear) on one side of the disk and an infrared sensor (red) on the other.

An on-board processor chip reads the pulses from the infrared sensors and turns them into binary data that the computer can understand. The chip sends the binary data to the computer through the mouse's cord.

The logic section of a mouse is dominated by an encoder chip, a small processor that reads the pulses coming from the infrared sensors and turns them into bytes sent to the computer. You can also see the two buttons that detect clicks (on either side of the wire connector).