In this tutorial I will talk about the types of computer mice. We will look at ball, optical and laser mice.

Types of computer mice

Computer mouse - a device with which you can select any objects on the computer screen and control them.

According to the connection method, they are wired and wireless. They differ from each other primarily in the principle of work. The most common types are:

• Ball;
• Optical;
• Laser.

Let's dwell on each type in more detail.

Ballpoint

The outdated and cheapest option is quite large, with a rubberized ball protruding slightly from the base.

By rotating it, it sets a certain direction for the two rollers inside, and they transmit them to special sensors, which "turn" the movement of the mouse into moving the cursor on the monitor.

But there is one drawback: if the ball gets dirty, the mouse starts to jam. Periodic cleaning is essential for normal operation. In addition, such a mouse requires a certain surface, because the accuracy depends on the grip of the device with it.

Optical

The optical computer mouse does not have rotating elements - the principle of its operation is qualitatively different from the previous version.

Its design is a small camera that takes up to a thousand pictures per second. When moving, the camera photographs the work surface, illuminating it. The processor processes these "snapshots" and sends a signal to the computer - the cursor moves.

Such a device can work on almost any surface, except for a mirror, and does not need cleaning. In addition, such a mouse is smaller and lighter than a ballpoint mouse.

The disadvantage of optical mice is that they glow when the computer is off. But this problem can be solved: the computer just needs to be disconnected from the voltage line.

By the way, in many modern models this issue is easily solved at all: on the mouse itself there is a special button that turns off the device.

Laser

The laser mouse is an advanced version of the optical mouse. The principle of operation is the same, only for backlighting, not an LED, but a laser is used.

This refinement made the device almost perfect: the mouse works on any surface (including glass and mirrors), it is more reliable, economical and accurate - the movement of the cursor matches the actual movement as much as possible.

In addition, even with the computer turned on, it is unlikely to interfere with sleep at night - the laser illumination is very weak.

Wired and wireless

Wired mice are connected to the computer using a special cable (wire).

Wireless ones do not have a “tail” - they transmit a signal to a computer via radio waves or via Bluetooth. They are connected using a special small receiver (very similar in appearance to a USB flash drive), which is inserted into the USB connector.

Of the shortcomings, it should be noted that all wireless, due to the lack of a cable, are deprived of stationary power. Therefore, they need to be recharged separately - from batteries and accumulators.

In addition, "tailless" can malfunction due to not always stable connection. Well, it should be noted that at a price they can significantly exceed the "tailed" ones.

Computer mouse buttons

Buttons are the main controls. It is with their help that the user performs basic actions: opens objects, selects, moves, and so on. Their number in modern models may fluctuate, but only two buttons and a scroll wheel are enough to work.

It is this version of a computer mouse - two buttons and a wheel - today the most common.

On a note . Often there are mice with a small button near the wheel. Its function is to double-click the left button.

Some modern mice have an additional button on the side, under the thumb. It can be programmed to perform some action: say, to open a specific program.

Fans of computer games respect it: it allows you to program the choice of weapons, which provides significant time savings in the game.

Manufacturers are constantly inventing something new, adding different buttons, but this does not bring tangible benefits - most users ignore them anyway.

True, there are some "non-standard" models that are used with pleasure by narrow specialists and gamers. For example, a trackball mouse (with a two-dimensional scroll wheel) or a mini-joystick (similar to a game joystick).

Modern mice

Regular two-button mouse has all the necessary qualities: it allows you to perform a lot of manipulations (clicks, drags and other gestures), easily gets into the desired pixel of the monitor, is suitable for long-term work and is relatively inexpensive.

Manufacturers are constantly updating the design, striving to make it more ergonomic, that is, as comfortable as possible to grip. So, today a user with any level of demands can choose the optimal model - both in terms of technical characteristics and the degree of comfort.

Apple introduced a touch mouse a few years ago. There are no buttons in it - control is carried out using gestures.

Another latest development is the so-called gyroscopic mouse... It recognizes movement not only on the surface, but also in the air - you can control it by swinging a brush.

True, such an innovation is far from perfect: the hand quickly gets tired when operating it.

3.1. How does a mouse work?

3.2. Mouse drivers in MS-DOS

3.3. Interrupt for mouse maintenance

3.1. How does a mouse work? Optical-mechanical mice

A mouse is a small box with two or three keys that connects to the computer with a thin cable:

Figure: 2. Mouse appearance

There are buttons on the top of the case. Usually there are two or three. The functions of these buttons are completely software-defined. A ball is visible below. It is usually covered with rubber for better grip on the table surface.

Structurally, the mouse is a streamlined plastic box, which contains:

A flexible cable connects the mouse to the computer system unit.

Figure 1 shows the internal structure of the mouse. The following compulsory mouse components are marked in the figure: 1 - Photo emitter 2 - Photo detector 3 - Ball 4 - Rotating roller 5 - Pressure wheel 6 - Button 7 - Cable 8 - Controller (special microcircuit)

The principle of operation of the mouse is as follows.

When the mouse button is pressed, the controller processes this event and sends information about the completed action to the computer.

When you move the mouse over the surface, the ball spins, and its rotation is transmitted to two mutually perpendicular rotating rollers, which generate movement signals "left-right", "up-down". Each of the two rotating rollers has a slotted disc. When the roller rotates, the rotating disc with slots passes (see Figure 2) or delays (see Figure 3) the beam that is emitted by the photo-emitter and received by the photodetector. The signal from the photodetector is processed by the controller and sent to the computer. Thus, the mechanical rotation of the mouse ball is converted into an electrical signal of its movement, and the rotation of the rollers is perceived and transmitted to the computer.

The software will associate mouse movements across the table surface with movements such as the cursor across the screen surface. By moving the mouse across the table (and, accordingly, the cursor across the screen), you can indicate (select) various objects on the screen.

If you open the mouse case, you will see a simple mechanism consisting of a ball, two axles with rubber pads, two discs with holes and four photo sensors:

Figure: 3. Internal structure of the mouse

When you move the mouse across the table surface, the rotation of the ball is transmitted through rubber rollers to two perforated discs. Near each disc there are photo sensors (two per disc). They fix the direction of rotation and the angle of rotation of the discs. As the mouse moves, the photosensors generate pulses that are transmitted to the computer. The number of these pulses is linearly dependent on the amount of mouse movement.

Nowadays, computer equipment manufacturers offer a wide range of different types of mice. Mice differ not only in appearance and the number of keys, but also in the way they are connected to a computer; mice can have different accuracy and different software interface.

There are two most commonly used methods of connecting a mouse to a computer:

through the serial port (COM1, COM2);

through a special adapter that is inserted into the expansion slot of the computer motherboard.

As for the software interface, there are two types:

three-button mouse Mouse Systems

microsoft two-button mouse

Some mice can emulate both types. The emulated type depends on the state of the switch on the bottom cover of the mouse or on whether the mouse button was pressed when the computer was powered on.

The computer mouse has its origins in December 9, 1968, when it was presented at the interactive devices exhibition in California. Douglas Engelbart received a patent for this gadget 2 years later. The first computer to include a mouse was the Xerox 8010 Star Information System mini-computer, introduced in 1981. The Xerox mouse had three buttons and cost $ 400, which is the equivalent of the current $ 1,000. In 1983, Apple released its own one-button mouse for the Lisa computer, which was reduced in price by 16 times. The computer mouse gained wide popularity thanks to its use in Macintosh computers. How does a modern computer mouse work - about this in today's issue.

Modern mice are of two types - optical and laser. Regardless of the type, the mouse perceives its movement in the working plane (for example, on a section of the table surface) and transmits this information to the computer. The program running on the computer, in response to the movement of the mouse, performs an action on the screen corresponding to the direction and distance of this movement.

The laser mouse first came out in 1998, being manufactured by Sun Microsystems. However, it did not become widespread then. Unlike an optical mouse, a laser mouse is capable of working on mirrored and transparent surfaces such as glass, which is a significant advantage.

The device and principle of operation of an optical mouse

Today, optical mice are no longer a surprise. But ten years ago, when the first generation of optical "rodents" only appeared, not many could boast of such an outlandish manipulator. Meanwhile, the ability to move the cursor using a "rodent" with a red LED in the "belly" was another step forward in computer technology.

Actually, the first optical mice had two LEDs, and one of them emitted light in the red range, and the other in the infrared. Accordingly, there were two photodiodes that worked "in tandem" with the above-mentioned LEDs. For such a mouse, a special mat with a surface made of a special reflective material was needed, on which a fine mesh of blue and black lines perpendicular to them was applied. The blue lines absorbed the light from the red LED, and the black lines absorbed the infrared.

Thus, one photodiode "noticed" the passage over the blue lines of the mat, and the other over the black ones. At the moment of passage over the line, the photodiode generated a corresponding electrical pulse. The mouse controller, counting the pulses, determined the direction and amount of movement.

We can say that the rug performed a function similar to that performed by the entire mechanical part in an optical-mechanical mouse (an ordinary mouse with a ball, which many have probably disassembled more than once).

The advantages of such mice include the absence of moving and inertial parts, reliability in operation, and positioning accuracy. And to the disadvantages - the rug, which required constant care and cleaning, and, as always (where without money), - a high cost. In addition, if the rug was lost or damaged, the mouse lost its performance. But in 1999, Agilent Technologies developed its own optical navigation technology, which did not require a rug at all. And since to date Agilent has produced more than 75 million sensors of various modifications for optical mice, it can be assumed that this technology came to the court of both manufacturers and users. In addition, the aforementioned company produces not only optical sensors, but also almost all the necessary components for assembling an optical mouse (a kind of do-it-yourself kit (see Fig. 1)), which makes the production of optical mice available even for small ones (so and I want to add "Chinese") companies. Figure 1 shows two lens and clip options. But whichever of them the manufacturer prefers, this does not fundamentally affect the operation of the optical system.

The essence of this technology is as follows: an optical sensor sequentially reads surface images (frames), and then mathematically determines the direction and amount of movement.

red

light-emitting diode

clip for led

The complete optical system consists of four components: optical sensor, lens, red LED and LED clip. How it looks assembled can be seen in Fig. 2.

Optic

The optical sensor includes three functional blocks: an image sensing system (IAS); digital signal processor (DPS); serial data interface.

Structurally, the optical sensor is a microcircuit with sixteen legs (although there is an option with eight), on the lower part of which (from the side of the legs) there is a lens.

Behind the lens is a monochrome CMOS (CMOS) camera, which photographs a small area of \u200b\u200bthe surface with an area of \u200b\u200babout a square millimeter. The surface frame is divided into small areas (squares). For each such area, the average brightness value is calculated. The range of assigned values \u200b\u200bis from 0 to 63, where 0 is assigned to the black area, and 63

White. Thus, a mosaic image is obtained, consisting of squares of different brightness. Here is one such square, i.e. image element, and is the anchor point, or rather, one sample (see Fig. 3). And the resolution of an optical mouse is defined in counts per inch, i.e. cpi, not dpi like in normal mice. Agilent manufactures sensors in both 400 and 800 cpi, and 800 cpi models can be programmed to operate at 400 cpi. By the way, some companies in the technical characteristics of their optical mice declare a resolution of 420 or 500 cpi. But looking through the technical documentation for various sensors, I have not seen such characteristics. And the fact that some small Chinese company produces sensors of its own design when such a recognized authority in this field of "thinking" as Logitech buys them from Agilent is very hard to believe. And if I have already mentioned Logitech, then I want to add that most of its models, with the exception of the cheapest ones, are equipped with sensors with a resolution of 800 cpi.

But back to technology. Keeping in mind that the sensor photographs a very small area of \u200b\u200bthe surface, and the cursor should move smoothly and without delay across the screen, and for this the sequentially read surface frames must overlap each other with a slight displacement, the surface is photographed at a very high speed - 1500 images per second ... This allows the mouse to move at speeds up to 12 inches (30 centimeters) per second. There are also sensor options that capture surfaces at 2,000 or 2,300 frames per second and move the mouse at 14 inches (35 cm) per second. Moreover, Microsoft claims that its latest developments include sensors with a shooting speed of 6,000 frames per second. Again, the datasheet at

i have not seen such a sensor, but I think that in this case it is quite possible. All of the above applies to the image reading system. Further, the captured frames are processed by a digital signal processor using a special, naturally patented algorithm. Comparing the received frames, the processor determines the amount and direction of mouse movement (see Fig. 3), and then converts this data into coordinates.

Since most of the sensors are quartzed with a generator with a frequency of 18 MHz (there are options for 24 MHz), it can be assumed that the power of the digital processor is 18 million operations per second. Then the calculated coordinates are transmitted to the computer using a serial interface. The first models of sensors were able to "communicate" with a computer via the PS / 2 interface, and an additional controller was required to work via the USB interface. By the way, the default frequency of sending coordinates when using the USB interface is 125 times per second, PS / 2 - 100 times. But through the serial port, some parameters of the sensor itself can be set - in particular, the resolution and the frequency of sending coordinates.

Now let's look at the purpose of other components of the optical system. Since it is dark under the arm even during the day, the surface that the sensor photographs must be illuminated. The sensor camera is set to perceive light in the red spectrum of radiation (l \u003d 639 nm). Therefore, a red LED is used, the main task of which is to ensure the operation of the sensor on the entire working surface even with a minimum amount of emitted light. The higher the illumination brightness, the more surfaces the sensor will work on.

To ensure uniform illumination of the surface, light from the LED is passed through the light guide and diffused by the lens. The sensor reads an image of the surface through the other lens. Structurally, two lenses and a light guide are made as one piece and are called with one word "lens".

In addition to the function of diffusing and focusing light, the lens performs another important function - protecting the sensor from electrostatic discharge. It is clear that the lens should be located at a strictly defined distance from the working surface and from the sensor. Therefore, the printed circuit board (PCB) and the supporting surface (base plate), on which the elements of the optical system are installed, must have strictly defined parameters, including the thickness. Well, the last element of the optical system is the latch. It serves to fix the elements of the optical system relative to each other.

At this point, you can leave the optical system alone and talk about the surface on which this system should work. Since the sensor uses microscopic surface features, the more features the better. These include surfaces with good texture (which any fabric possesses) and patterned features. Optical mice work quite well on plain white paper. But with any reflective surface, the sensor does not work well, be it a mirror, glass, or just a plastic surface of the mat. Also among the "bad" surfaces are halftone surfaces and rugs with a three-dimensional image.

But be that as it may, such positive aspects as the absence of moving parts, precise positioning, smooth and light movements make the optical mouse quite an attractive object to buy.

And if you take mice in the price range up to $ 20, then, most likely, they will have the same type of sensor and, accordingly, identical characteristics. In this case, you should pay attention to the ergonomics of the product, the presence

additional buttons, quality of materials and manufacturer's name. Plus, build quality is an important consideration for optical mice. And if you hear the name of the company for the first time, then you should think about whether to take such a mouse or not. In any case, before buying it does not hurt to read reviews dedicated to specific models.

That's probably all. Good luck.

Igor Maslovsky, [email protected]

The light guide is raised above the microcircuit

Lens and diffuser

View of the objective part of the optical mouse

Bottom view of the assembled objective part

In previous articles, we began to tell you about computer peripherals. We started with the keyboard. Next in line is the mouse. In the article, we will tell you about what a computer mouse is, what their types and main characteristics are.

Computer mouse - an integral part of the computer. It allows the user to control the cursor, which is displayed on the screen, by moving the mouse itself over the table surface.

Simply put, a computer mouse is a means by which we can select objects on the computer screen and control them. These actions include: copying, opening documents, highlighting and text, and much more. When using a computer, a person practically does not let go of the device, which proves the importance of this device.

What does a computer mouse consist of

Mice for a computer, if you do not pay attention to the features of some types, consist of a scroll wheel with which you can move (scroll through information) on the computer screen, and keys that are used for such actions as, for example: activate the context menu, activate or open object, grab and move it, etc.

On the underside of the mouse is a sensor for tracking the movement of the manipulator along the surface. Depending on the type (will be discussed below) it can be a ball (practically not used in our time) or a laser scanner.

Also, the mouse has either a cable (with USB or PS / 2 interface) that connects it to a PC, or, in the case of wireless mice, a compartment for installing batteries.

Types of computer mice

The computer mouse has come a long way of evolution and today we know the following types of them:

• Mechanical - a type of mouse that is practically not used today. A device made of a rubberized steel ball, rollers and angle sensors is used here as a movement tracking sensor. As the mouse moves, the steel ball spins, rollers are pressed against it, which fix this and transmit information to the rotation angle sensors. The sensors, in turn, convert the received data into electrical signals. The disadvantages of such mice are their relatively large size and the need for periodic cleaning for good performance. She also needs a rug, without it it will be impossible to work with a manipulator;
• Optical - differ from mechanical ones in that instead of a ball, to track the movement, a "camera" is used which, with a frequency of several hundred frames per second, photographs the surface on which the mouse moves. Analyzing the captured images, the cursor moves on the screen. In order to better highlight all surface irregularities, and therefore improve the quality of mouse positioning, a bright LED is used, which is installed in the device at a slight angle;
• Laser - a great alternative to the previous type of mouse. The principle of operation can be called identical to optical, only in this type, instead of an LED, an infrared laser diode is used for illumination. Thanks to this solution, the positioning accuracy of the device increases. Another advantage is that the type of surface is practically not important for the correct operation of a laser mouse;
• Sensory - here the name speaks for itself. This mouse has no buttons or a scroll wheel, all commands can be set using gestures. Touch mice are the latest in ease of use and amazing looks;
• Induction - mice that work by using induction energy. In use, a rug is required, which serves as a so-called graphic tablet;
• Trackball Mouse - devices without buttons, which are controlled by an inverted ball called a trackball;
• Gyroscopic - the positioning of the cursor with such a mouse is due to the gyroscope. For correct operation, the surface is not important for these mice, they read information about the movement not only from it, but from space.

Another way to classify computer mice is by dividing them according to the connection method. So mice are:

• Wired - connect to a PC using a USB or PS / 2 cable;
• Wireless - the connection is made using the Bluetooth protocol.

Characteristics of computer mice

The main characteristics of computer mice:

1. Type (kind) ... As mentioned above, this affects the operation of the mouse itself, convenience and practicality. Each user individually chooses the item of use, since the basis is the purpose: there are those who actively play computer games - a gaming mouse is ideal for him, since it is equipped with additional keys for easy navigation. For others, the usual laser will be enough, with the help of which they will perform all the operations necessary for the average user.
2. Size and shape ... These characteristics primarily affect its practicality in use: the choice, in most cases, is determined by the size of the hand - girls love small and beautiful mice, men are used to feeling in their hands a weighty and rather large mouse that will be convenient to control.
3. Sensitivity ... This criterion affects the accuracy of the cursor movement on the screen. More experienced users pay great attention to sensitivity, since, in addition to the standard settings, in some of their activities, maximum accuracy and balance of movements is needed, which can affect the result of work.

conclusions

To date, a large number of the presented types of computer mice enable each person to make a balanced choice based on individual requirements. I hope that the article helped you to learn a lot about such an indispensable subject for a computer user as a mouse.