The Computer Mouse
Most computer users in the Milford NH area have required at least some form of computer repair in the past, but almost never because of a failed or nonfunctional computer mouse, for the 'mouse' is a hardy little creature indeed. Here we take a look at its origin and evolution.

Introduction
The computer mouse, a pointing device which is able to detect two-dimensional motion in relation to a certain type of surface. These motions are translated to the pointer on computer display and this allows for control of a graphical user interface. Commonly, the mouse features two or more buttons and is held in one's hand. 

The computer mouse was first invented during the 1960's by Dr. Douglas Engelbart with assistance of Bill English and it was first referred to as a "X-Y Position Indicator for a Display System." This mouse was patented in 1970 and was first used with the Xerox Alto computer system in 1973, the first minicomputer system with a graphical user interface. Additionally, the mouse featured elements such as touch surfaces and wheels. These features provided even more control and extra dimensional input. Later, the wheels were replaced by the ball, which was able to monitor movement in any direction.

The Anatomy of a Computer Mouse
The skin of the mouse consists of the hard plastic body which a user can guide across a flat surface. The tail of the computer mouse is the electrical cable connecting the mouse with the Central Processing Unit. At the back end of the tail, one to three buttons are external contacts to the electrical switches. The press of a certain button will close the switch with what is called a click, and by doing so, the circuit is closed and therefore the computer will receive a command.

On the bottom side of a computer mouse, in the case of the rubberized ball mouse - the ball is found in a plastic hatch which fits over it. Inside, two shafts and a support wheel keep the ball in place. As the ball rolls around, one shaft will turn horizontal motion and the other will respond to vertical motion. The wheel will also turn, at any end of the two shafts.

The brain of a computer mouse consists of its own software called a mouse driver. This driver actually serves as an external brain which actively enables the computer to understand the signals sent by the mouse. The same driver lets the computer know how to interpret the IC data stream of the mouse, including speed, click-commands and the direction. While most mice which are purchased as part of a computer bundle have these drivers pre-programmed, some mouse drivers allow the user to program the mouse themselves, and therefore assign certain actions to the buttons.
Some of the Different Types of Computer Mice

The Optical Mouse
In 1980, the first optical mouse was developed and it eliminated the troubled ball which was used in computer mice by then. The ball often became dusty and dirty while being rolled around. Nevertheless, the cost of manufacturing these was too high to be used widely, and it wasn't until the 1998 that the optical mouse became a commercially acceptable alternative to the ball mouse. As we know, the optical mouse completely replaced the ball mouse, as it is supplied with all new computer systems.

With the optical mouse, a LED sensor is used to detect and track movement across the surface, the small LED sensor is found on the bottom of the mouse. To detect connection issues, the LED is programmed to light up when the mouse is operational. The light is most commonly red, but there are optical mice with different LED colors. No mouse pad is required to operate an optical mouse, and the sensor can be easily cleaned with a cotton swab, if the signal gets blocked.

The Laser Mouse
Very similarly to the optical mouse, the laser mouse uses a laser to track the movement of the mouse itself and to translate these movements to the computer screen. These small lasers are precision instruments, which make the laser mice more sensitive but allow them to move more quickly and accurately. The laser mice also don't require any type of a mouse pad to be operated, and can also be easily cleaned if needed.

The Trackball 
Originally, the trackball was a part of a WW II-era radar system named Comprehensive Display System (CDS). It was invented by Ralph Benjamin while he worked for the British Royal Navy Scientific Service. Benjamin invented the trackball when he felt the need for a more precise and elegant input device, while users of his project used joysticks until then. The trackball was patented in 1947, but only prototypes were made and these used a metal ball rolling on to two rubber-coated wheels. The device was first kept as a military secret.

Today, we know the trackball as a peripheral which follows a  very similar definition of a computer mouse. It is a pointing device as well and it consists of a ball held in a socket in which sensors allow rotation detection of the ball. The trackball is often referred to as being an upside-down mouse because of its exterior design, the ball being on top unlike mechanical mice in which the ball is on the bottom. The trackball allows users to roll the ball with their fingers, the palm or with the thumb - in order to move the pointer on screen.

The trackball has some notable advantages over the standard mouse. For example, a mouse can reach an edge of its operating area while one would like to move it even further, but is therefore limited by its design. The trackball can be rolled continuously allowing for unlimited movement in any direction without the users having to lift or re-position the device.

Other Types of Computer Mice
The types of computer mice mentioned above are only some of the most common ones. Other, specialized types of mice are available. One of these are the wireless mice, which give you the advantage of operating one without being strictly limited to the reach of the cable. 

One other example of a neat pointing device is the trackpad. The trackpad uses a tactile sensor along with a specialized surface which translated movement and position of one's fingers and this motion is outputted to the computer screen. Touchpads are most common on laptop computer, but are also used along with personal digital assistants (PDAs) and some other portable media players. Wireless touchpads also exists, for example, Apple's Magic Trackpad, which is pretty much a detached accessory.

---