Category Computer

An optical mouse is technologically much more advanced than a mechanical mouse. Unlike the latter, an optical mouse is completely electronic and therefore has no moving parts. It consists of an LED (that generates the signature red light), a light-detector chip, a switch mechanism and a few other simple components. Some mice have another LED that lights up a plastic strip installed at the back of the mouse as an indication of the mouse’s operation.

The LED installed at the bottom of the mouse emits a bright light in the downward direction. Since a mouse is usually used on plain surfaces, the light bounces back from the surface and enters a photocell that’s also mounted on the bottom, almost next to the LED. This photocell has a frontal lens that magnifies any light reaching it. As you move the mouse around, the pattern of the reflected beam changes; this is then used by the light-detector chip to figure out how and in which direction you’re moving the mouse.

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.

Optical mice are much lighter and faster than mechanical ones, and have therefore gained enormous popularity all over the world. With improvements in technology, newer and even more advanced mice – that address issues like ergonomics and the health of the user – are taking center stage. The choice of the right variant rests with the user, but one thing remains universally true – computers and mice shall always remain inseparable.

A Mouse is a device for giving the computer information (an input device). When the mouse is pushed around on a mat, a pointer on the computer’s screen is moved, indicating how data needs to be changed, moved or processed. Tiny beams of light inside the mouse shine through slotted wheels. The ball of the mouse moves as it is pushed across the mat, and the beams of light are interrupted in a way that tells the computer the direction that the mouse is moving.

A mouse is something you push along your desktop to make a cursor (pointing device) move on your screen. So what a mouse has to do is figure out how much you’re moving your hand and in which direction. There are two main kinds of mice and they do this job in two different ways, either using a rolling rubber ball (in a ball-type mouse) or by bouncing a light off your desk (in an optical mouse).

How does a mouse like this actually work? As you move it across your desk, the ball rolls under its own weight and pushes against two plastic rollers linked to thin wheels. 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).

How do the wheels measure your hand movements? As you move the mouse, the ball moves the rollers that turn one or both of the wheels. If you move the mouse straight up, only the y-axis wheel turns; if you move to the right, only the x-axis wheel turns. And if you move the mouse at an angle, the ball turns both wheels at once. Now here’s the clever bit. Each wheel is made up of plastic spokes and, as it turns, the spokes repeatedly break a light beam. The more the wheel turns, the more times the beam is broken. So counting the number of times the beam is broken is a way of precisely measuring how far the wheel has turned and how far you’ve pushed the mouse. The counting and measuring is done by the microchip inside the mouse, which sends details down the cable to your computer. Software in your computer moves the cursor on your screen by a corresponding amount.

There are various problems with mice like this. They don’t work on all surfaces. Ideally, you need a special mouse mat but, even if you have one, the rubber ball and its rollers gradually pick up dirt, so the x- and y-axis wheels turn erratically and make the pointer stutter across your screen. One solution is to keep taking your mouse to pieces and cleaning it; another option is to get yourself an optical mouse.

Traditional mice have a rubber ball inside them. Open one up and you can see the heavy ball clearly and the spring that keeps it in position.

(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. (10) Electrolytic capacitor (11) Resistors. (See picture):

Inside a computer is a “hard disk”, which is able to store information (data) even when the machine is turned off. There are also two other kinds of storage in a computer. ROM (read-only memory) stores the instructions that tell the computer how to start working when it is first switched on. RAM (random-access memory) stores data that is in use. To make sure that data is permanently stored, it must be “saved” on the hard disk before the computer is switched off.

At the core of the computer is the central processing unit or CPU, the source of control that runs all programs and instructions. In order to function, computers use two types of memory: primary and secondary. The main storage is the primary memory, and data and programs are stored in secondary memory.

Data is stored as lots of binary numbers, by magnetism, electronics or optics. … The computer’s operating system, for example, contains instructions for organizing data into files and folders, managing temporary data storage, and sending data to application programs and devices such as printers.

Magnetic storage is commonly used on the hard disc drives found on most computers. Information is stored using positive and negative magnetic charges to correspond with the 1s and 0s noted above. Optical discs like CDs and DVDs store information as binary code that can be read by an optical sensor in a disc drive.

The hardware of a computer consists of all the parts you can hold in your hand: the machine itself and any other machinery that is attached to it. But a computer by itself is simply a collection of components. In order to do anything at all, it must be programmed (given a set of instructions). Programs are what are known as software. They are written in a code that a computer can “understand” and act upon. The codes in which programs are written are sometimes called languages.

Computer hardware is any physical device used in or with your machine, whereas software is a collection of programming code installed on your computer’s hard drive. In other words, hardware is something you can hold in your hand, whereas software cannot be held in your hand. You can touch hardware, but you cannot touch software. Hardware is physical, and software is virtual.

For example, the computer monitor you are using to read this text, and the mouse you are using to navigate this web page are computer hardware. The Internet browser allowing you to view this page, and the operating system that the browser is running on are considered software. A video card is hardware, and a computer game is software. You can touch and feel the video card, and the computer uses it to play a computer game, but you cannot touch or feel the programming code that makes up the computer game.

All software utilizes at least one hardware device to operate. For example, a video game, which is software, uses the computer processor (CPU), memory (RAM), hard drive, and video card to run. Word processing software uses the computer processor, memory, and hard drive to create and save documents.

Hardware is what makes a computer work. A CPU processes information and that information can be stored in RAM or on a hard drive. A sound card provides sound to speakers, and a video card provides an image to a monitor. Each of these are examples of hardware components.

The central processing unit (CPU) is the “brain” of a computer, where its calculations take place. It is contained within a larger processing unit. In order to give instructions to the computer, input devices, such as a keyboard, stylus, mouse, or joystick, are needed. The monitor enables the user to see data on a screen. Many other machines, called peripherals, can also be connected to the computer. They include printers, scanners and modems.

The Central Processing Unit

The central processing unit, or CPU, can be thought of as the “brain” of a computer. Using a combination of arithmetic functions, logic processes and input/output commands, the CPU receives instructions from various computer programs in use and executes them as needed. The modern CPU exists in the form of a microprocessor, which features a single integrated circuit design. This is a dramatic departure from the earliest CPU units, which featured a transistor-based construction. Compared to the CPUs used in the second half of the 20th century, modern hardware is highly efficient, portable and relatively inexpensive to manufacture.

The Motherboard

A CPU can’t achieve its intended purpose without the assistance of the motherboard. The motherboard is a printed circuit board, or PCB, found inside a computer which not only hosts the CPU but also acts as a connected gateway to various other computer peripherals, including sound cards, hard drives, video cards and so on. The motherboard hosts a number of sockets into which microprocessors, such as the CPU, can be plugged. The motherboard is also connected to the computer’s power supply and distributes electrical voltage to the attached components. Simply put, a motherboard provides a critical platform on which the rest of a CPU’s hardware can operate. Without the motherboard in place, a computer couldn’t function.

Hard Drives and RAM

The hard drive often shortened to HD, stores data which can then be accessed by various other programs at any given time. Hard drives provide users with various levels of storage capacity, with more expensive units often providing greater space for data storage and faster rates of data transmission.

It’s somewhat easy to confuse the function of the hard drive with that of random access memory, or RAM. Unlike a hard drive, RAM is composed of a series of chips which allow for temporary data storage only. Whereas a hard drive will continue to store data even after a computer has been powered off, RAM will be cleared. RAM is often used to act as a holding zone for open files or critical data that a program may need to access intermittently during use. RAM should not be thought of as storage, per say, but instead as a “place holder” for valuable information. Nevertheless, it remains one of the 4 main parts of a computer that is still in use today.

Monitor

The monitor works with a video card, located inside the computer case, to display images and text on the screen. Most monitors have control buttons that allow you to change your monitor’s display settings, and some monitors also have built-in speakers.

Keyboard

The keyboard is one of the main ways to communicate with a computer. There are many different types of keyboards, but most are very similar and allow you to accomplish the same basic tasks.

Mouse

The mouse is another important tool for communicating with computers. Commonly known as a pointing device, it lets you point to objects on the screen, click on them, and move them. There are two main mouse types: optical and mechanical. The optical mouse uses an electronic eye to detect movement and is easier to clean. The mechanical mouse uses a rolling ball to detect movement and requires regular cleaning to work properly.

In the early 1830s, an English inventor called Charles Babbage (1792-1871) designed the first programmable computer and began to build it. In fact, he never finished, as the machine was extremely complicated! This computer was entirely mechanical. Over a hundred years had to pass before the electronic components that are used today were invented.

We could argue that the first computer was the abacus or its descendant, the slide rule, invented by William Oughtred in 1622. But the first computer resembling today’s modern machines was the Analytical Engine, a device conceived and designed by British mathematician Charles Babbage between 1833 and 1871. Before Babbage came along, a “computer” was a person, someone who literally sat around all day, adding and subtracting numbers and entering the results into tables. The tables then appeared in books, so other people could use them to complete tasks, such as launching artillery shells accurately or calculating taxes.

It was, in fact, a mammoth number-crunching project that inspired Babbage in the first place [source: Campbell-Kelly]. Napoleon Bonaparte initiated the project in 1790, when he ordered a switch from the old imperial system of measurements to the new metric system. For 10 years, scores of human computers made the necessary conversions and completed the tables. Bonaparte was never able to publish the tables, however, and they sat collecting dust in the Academia des sciences in Paris.

In 1819, Babbage visited the City of Light and viewed the unpublished manuscript with page after page of tables. If only, he wondered, there was a way to produce such tables faster, with less manpower and fewer mistakes. He thought of the many marvels generated by the Industrial Revolution. If creative and hardworking inventors could develop the cotton gin and the steam locomotive, then why not a machine to make calculations [source: Campbell-Kelly]?

Babbage returned to England and decided to build just such a machine. His first vision was something he dubbed the Difference Engine, which worked on the principle of finite differences, or making complex mathematical calculations by repeated addition without using multiplication or division. He secured government funding in 1824 and spent eight years perfecting his idea. In 1832, he produced a functioning prototype of his table-making machine, only to find his funding had run out.