Optical mouse device. Basic characteristics of a computer mouse. Basic malfunctions of computer mice

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

Types of computer mice

Computer mouse is a device with which you can select and manipulate objects on the computer screen.

Depending on the connection method, there are wired and wireless. They differ from each other primarily in their operating principle. The most common types are:

• Ball;
• Optical;
• Laser.

Let's look at each type in more detail.

Ball

Outdated and cheapest option - enough big size, with a rubberized ball protruding slightly from the base.

With its rotation, it sets a certain direction to the two rollers inside, and they transmit them to special sensors, which “transform” the movement of the mouse into the movement of 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 proper operation. In addition, such a mouse requires a certain surface, because the accuracy of the work depends on the adhesion of the device to it.

Optical

An 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. As you move, 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 mirror, and does not require cleaning. In addition, such a mouse is smaller and lighter than a ball mouse.

The disadvantage of optical mice is that they glow when the computer is turned 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 can be easily resolved: on the mouse itself there is a special button that turns off the device.

Laser

A laser mouse is an improved version of an optical mouse. The principle of operation is the same, only a laser is used for illumination rather than an LED.

This modification made the device almost ideal: the mouse works on any surface (including glass and mirror), it is more reliable, economical and accurate - cursor movements closely correspond to real movement.

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

Wired and wireless

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

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

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

In addition, “tailless” devices may have operational failures due to a connection that is not always stable. Well, it should be noted that in price they can significantly exceed the “tailed” ones.

Computer mouse buttons

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

This is exactly the option computer mouse- two buttons and a wheel - the most common today.

On a note . There are often mice that have 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 any actions: say, to open a certain program.

Fans of computer games treat it with respect: 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 any tangible benefit - most users ignore them anyway.

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

Modern mice

Regular two-button mouse has all the necessary qualities: it allows you to perform many manipulations (clicking, dragging and other gestures), easily hits the desired pixel on the monitor, is suitable for long-term work and is relatively inexpensive.

Manufacturers are constantly updating the design, trying to make it more ergonomic, that is, as comfortable as possible for grip. So choose the optimal model - and according technical specifications, and in terms of comfort - today a user with any level of requests can.

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

Another one latest development- so-called gyroscopic mouse. It recognizes movement not only on the surface, but also in the air - you can control it by waving your hand.

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

In this article, we will look at the principles of operation of optical mouse sensors, shed light on the history of their technological development, and also debunk some myths associated with optical “rodents”.

Who invented you...

Optical mice that are familiar to us today trace their origins back to 1999, when the first copies of such manipulators from Microsoft, and after some time from other manufacturers, appeared on mass sale. Before the appearance of these mice, and for a long time after that, most of the mass-produced computer “rodents” were optomechanical (the movements of the manipulator were monitored optical system, associated with the mechanical part - two rollers responsible for tracking the movement of the mouse along the × and Y axes; these rollers, in turn, were rotated by a ball that rolled as the user moved the mouse). Although there were also purely optical mouse models that required a special mouse pad for their operation. However, such devices were not encountered often, and the very idea of ​​developing such manipulators gradually faded away.

The “type” of mass-produced optical mice familiar to us today, based on general operating principles, was “developed” in the research laboratories of the world-famous Hewlett-Packard corporation. More precisely, in its division Agilent Technologies, which only relatively recently was completely separated into a separate company within the structure of HP Corporation. Today, Agilent Technologies, Inc. - a monopolist in the market of optical sensors for mice; no other companies develop such sensors, no matter who tells you about the exclusive technologies IntelliEye or MX Optical Engine. However, enterprising Chinese have already learned to “clone” Agilent Technologies sensors, so by buying an inexpensive optical mouse, you may well become the owner of a “left-handed” sensor.

We will find out where the visible differences in the operation of the manipulators come from a little later, but for now let us begin to consider the basic principles of the operation of optical mice, or more precisely, their movement tracking systems.

How computer mice “see”

In this section, we will study the basic principles of operation of optical motion tracking systems that are used in modern mouse-type manipulators.

So, an optical computer mouse gains “vision” through the following process. Using an LED and a system of lenses that focus its light, an area of ​​the surface under the mouse is illuminated. The light reflected from this surface, in turn, is collected by another lens and hits the receiving sensor of the microcircuit - the image processor. This chip, in turn, takes pictures of the surface under the mouse with high frequency(kHz). Moreover, the microcircuit (let's call it an optical sensor) not only takes pictures, but also processes them, since it contains two key parts: a receiving system Images Acquisition System (IAS) and integrated DSP image processor.

Based on the analysis of a series of consecutive images (representing a square matrix of pixels of different brightness), the integrated DSP processor calculates the resulting indicators indicating the direction of mouse movement along the × and Y axes, and transmits the results of its work externally via the serial port.

If we look at the block diagram of one of the optical sensors, we will see that the chip consists of several blocks, namely:

• the main block is, of course, ImageProcessor- image processing processor (DSP) with built-in light signal receiver (IAS);
• Voltage Regulator And Power Control- voltage regulation and energy consumption control unit (power is supplied to this unit and an additional external voltage filter is connected to it);
• Oscillator- this chip block is supplied external signal from a master quartz oscillator, the frequency of the incoming signal is about a couple of tens of MHz;
• Led Control- this is an LED control unit that illuminates the surface under the mouse;
• Serial Port- a block that transmits data about the direction of mouse movement outside the chip.

We will look at some details of the operation of the optical sensor chip a little further, when we get to the most advanced of modern sensors, but for now we will return to the basic principles of operation of optical systems for tracking the movement of manipulators.

It should be clarified that the optical sensor chip does not transmit information about mouse movement via the Serial Port directly to the computer. The data goes to another controller chip installed in the mouse. This second “main” chip in the device is responsible for responding to mouse button presses, scroll wheel rotation, etc. This chip, among other things, directly transmits information about the direction of mouse movement to the PC, converting data coming from the optical sensor into data transmitted via PS/2 or USB signals. And the computer, using the mouse driver, based on the information received through these interfaces, moves the pointer across the monitor screen.

It is precisely because of the presence of this “second” controller chip, or rather thanks to different types such microcircuits, already the first models of optical mice differed quite noticeably from each other. If I can’t speak too badly about expensive devices from Microsoft and Logitech (although they were not at all “sinless”), then the mass of inexpensive manipulators that appeared after them did not behave quite adequately. When these mice moved on ordinary mouse pads, the cursors on the screen made strange somersaults, jumped almost to the floor of the Desktop, and sometimes... sometimes they even went on an independent journey across the screen when the user did not touch the mouse at all. It even got to the point that the mouse could easily wake the computer from standby mode, erroneously registering a movement when no one was actually touching the manipulator.

By the way, if you are still struggling with similar problem, then it can be solved in one fell swoop like this: select My Computer > Properties > Hardware > Device Manager > select installed mouse> go to its “Properties” > in the window that appears, go to the “Power Management” tab and uncheck the “Allow the device to wake the computer from standby mode” option (Fig. 4). After this, the mouse will no longer be able to wake up the computer from standby mode under any pretext, even if you kick it :)

So, the reason for such a striking difference in the behavior of optical mice was not at all the “bad” or “good” installed sensors, as many still think. Don't believe it, this is nothing more than a myth. Or fantasy, if you prefer :) Mice that behaved completely differently often had exactly the same optical sensor chips installed (fortunately, there were not so many models of these chips, as we will see later). However, thanks to imperfect controller chips installed in optical mice, we had the opportunity to strongly criticize the first generations of optical rodents.

However, we are somewhat distracted from the topic. Let's go back. In general, the mouse optical tracking system, in addition to the sensor chip, includes several more basic elements. The design includes a holder (Clip) in which the LED and the sensor chip itself are installed. This system of elements is attached to printed circuit board(PCB), between which and the bottom surface of the mouse (Base Plate) a plastic element (Lens) is fixed, containing two lenses (the purpose of which was written above).

When assembled, the optical tracking element looks like the one shown above. The operating diagram of the optics of this system is presented below.

The optimal distance from the Lens element to the reflective surface under the mouse should be in the range from 2.3 to 2.5 mm. These are the recommendations of the sensor manufacturer. Here is the first reason why optical mice don’t feel good when “crawling” on plexiglass on a table, all sorts of “translucent” rugs, etc. And you shouldn’t glue “thick” legs to optical mice when the old ones fall off or wear off. Due to excessive “elevation” above the surface, the mouse can fall into a state of stupor, when “moving” the cursor after the mouse is at rest becomes quite problematic. This is not theoretical speculation, this is personal experience :)

By the way, about the problem of durability of optical mice. I remember that some of their manufacturers claimed that, they say, “they will last forever.” Yes, the reliability of the optical tracking system is high, it cannot be compared with the optomechanical one. At the same time, in optical mice there are many purely mechanical elements that are subject to wear and tear in the same way as under the dominance of the good old “opto-mechanics”. For example, the legs of my old optical mouse were worn out and fell off, the scroll wheel broke (twice, the last time irrevocably :()), the wire in the connecting cable frayed, the housing cover peeled off the manipulator... but the optical sensor works normally, as if nothing was wrong happened. Based on this, we can safely state that the rumors about the supposedly impressive durability of optical mice have not been confirmed in practice. And why, pray tell, do optical mice “live” for too long? After all, new, longer ones are constantly appearing on the market? perfect models created on a new element base. They are obviously more perfect and easier to use. Progress, you know, is a continuous thing. Let’s see what it has been like in the field of the evolution of the optical sensors that interest us.

From the history of mouse vision

Development engineers at Agilent Technologies, Inc. No wonder they eat their bread. Over the past five years, this company's optical sensors have undergone significant technological improvements and their latest models have very impressive characteristics.

But let's talk about everything in order. Microcircuits became the first mass-produced optical sensors HDNS-2000(Fig. 8). These sensors had a resolution of 400 cpi (counts per inch), that is, dots (pixels) per inch, and were designed for a maximum mouse movement speed of 12 inches/s (about 30 cm/s) with an optical sensor image rate of 1500 frames in a second. Acceptable (while maintaining stable operation of the sensor) acceleration when moving the mouse “in a jerk” for the HDNS-2000 chip is no more than 0.15 g (approximately 1.5 m/s2).

Then optical sensor chips appeared on the market ADNS-2610 And ADNS-2620. The ADNS-2620 optical sensor already supported a programmable frequency of “capturing” the surface under the mouse, with a frequency of 1500 or 2300 images/s. Each photo was taken with a resolution of 18x18 pixels. For the sensor, the maximum operating speed of movement was still limited to 12 inches per second, but the limit on permissible acceleration increased to 0.25 g, with a frequency of “photographing” the surface of 1500 frames/s. This chip (ADNS-2620) also had only 8 legs, which made it possible to significantly reduce its size compared to the ADNS-2610 chip (16 pins), which was similar in appearance to the HDNS-2000. At Agilent Technologies, Inc. set out to “minimize” their microcircuits, wanting to make them more compact, more energy-efficient, and therefore more convenient for installation in “mobile” and wireless manipulators.

The ADNS-2610 chip, although it was a “large” analogue of the 2620, was deprived of support for the “advanced” mode of 2300 pictures/s. In addition, this option required 5V power, while the ADNS-2620 chip required only 3.3V.

Coming soon chip ADNS-2051 was a much more powerful solution than the HDNS-2000 or ADNS-2610 chips, although it was also similar in appearance (packaging). This sensor already made it possible to programmably control the “resolution” of the optical sensor, changing it from 400 to 800 cpi. The chip version also allowed adjustment of the frequency of surface images, and allowed it to be changed in a very wide range: 500, 1000, 1500, 2000 or 2300 images/s. But the size of these same pictures was only 16x16 pixels. At 1500 shots/s, the maximum permissible acceleration of the mouse during a “jerk” was still 0.15 g, the maximum possible movement speed was 14 inches/s (i.e. 35.5 cm/s). This chip was designed for a supply voltage of 5 V.

Sensor ADNS-2030 developed for wireless devices, and therefore had low power consumption, requiring only 3.3 V power. The chip also supported energy-saving functions, for example, the function of reducing energy consumption when the mouse is at rest (power conservation mode during times of no movement), switching to sleep mode, including when the mouse is connected via a USB interface, etc. The mouse, however, could not operate in power-saving mode: the value “1” in the Sleep bit of one of the chip’s registers made the sensor “always awake,” and the default value “0” corresponded to the operating mode of the chip when, after one second, if. the mouse did not move (more precisely, after receiving 1500 completely identical images of the surface), the sensor, together with the mouse, went into power saving mode. As for the other key characteristics of the sensor, they did not differ from those of the ADNS-2051: the same 16-pin body, movement speed up to 14 inches/s with a maximum acceleration of 0.15 g, programmable resolution 400 and 800 cpi, respectively, picture frequencies could be exactly the same as that of the above-considered version of the microcircuit.

These were the first optical sensors. Unfortunately, they were characterized by shortcomings. A big problem that arose when moving an optical mouse over surfaces, especially those with a repeating small pattern, was that the image processor would sometimes confuse separate similar areas of the monochrome image received by the sensor and incorrectly determine the direction of mouse movement.

As a result, the cursor on the screen did not move as required. The pointer on the screen even became capable of impromptu :) - unpredictable movements in any direction. In addition, it is easy to guess that if you move the mouse too quickly, the sensor could completely lose any “connection” between several subsequent images of the surface. Which gave rise to another problem: when the mouse moved too sharply, the cursor either twitched in one place, or even “supernatural” phenomena occurred, for example, with the rapid rotation of the surrounding world in toys. It was absolutely clear that for the human hand, the limitations of 12-14 inches/s on the maximum speed of mouse movement were clearly not enough. There was also no doubt that the 0.24 s (almost a quarter of a second) allocated to accelerate the mouse from 0 to 35.5 cm/s (14 inches/s - maximum speed) is a very long period of time; a person is able to move the hand much faster. And therefore, with sudden movements of the mouse in dynamic gaming applications with an optical manipulator, it can be difficult...

Agilent Technologies also understood this. The developers realized that the characteristics of the sensors needed to be radically improved. In their research, they adhered to a simple but correct axiom: the more pictures per second the sensor takes, the less likely it is that it will lose the “trace” of the mouse movement while the computer user makes sudden body movements :)

Although, as we see from the above, optical sensors have been developing, new solutions are constantly being released, but development in this area can safely be called “very gradual.” By and large, there have been no fundamental changes in the properties of the sensors. But technological progress in any field is sometimes characterized by sharp leaps. There was such a “breakthrough” in the field of creating optical sensors for mice. The advent of the ADNS-3060 optical sensor can be considered truly revolutionary!

Best of

Optical sensor ADNS-3060, in comparison with its “ancestors”, has a truly impressive set of characteristics. The use of this chip, packaged in a 20-pin package, provides optical mice with unprecedented capabilities. Acceptable maximum speed the movement of the manipulator increased to 40 inches/s (that is, almost 3 times!), i.e. reached a “signature” speed of 1 m/s. This is already very good - hardly at least one user moves the mouse with more than this limitation speed so often that you constantly feel discomfort from using the optical manipulator, including gaming applications. The permissible acceleration has increased, scary to say, a hundred times (!), and reached a value of 15 g (almost 150 m/s2). Now the user is given 7 hundredths of a second to accelerate the mouse from 0 to the maximum 1 m/s - I think that very few people will now be able to exceed this limitation, and even then, probably in their dreams :) The programmable speed of taking pictures of the surface with the optical sensor of the new chip model exceeds 6400 fps, i.e. "beats" the previous "record" almost three times. Moreover, the ADNS-3060 chip can itself adjust the frequency of snapshots to achieve the most optimal operating parameters, depending on the surface over which the mouse moves. The “resolution” of the optical sensor can still be 400 or 800 cpi. Let's use the ADNS-3060 chip as an example to look at the general principles of operation of optical sensor chips.

The general scheme for analyzing mouse movements has not changed compared to earlier models - micrographs of the surface under the mouse obtained by the IAS sensor block are then processed by a DSP (processor) integrated in the same chip, which determines the direction and distance of movement of the manipulator. The DSP calculates the relative magnitudes of the × and Y coordinates relative to the mouse's home position. Then the external microcircuit of the mouse controller (what it is needed for, we said earlier) reads information about the movement of the manipulator from serial port optical sensor chips. Then this external controller translates the received data about the direction and speed of mouse movement into signals transmitted via standard PS/2 or USB interfaces, which are then sent to the computer.

But let’s delve a little deeper into the features of the sensor. The block diagram of the ADNS-3060 chip is shown above. As we see, its structure has not changed fundamentally, compared to its distant “ancestors”. 3.3 Power is supplied to the sensor through the Voltage Regulator And Power Control block; the same block is charged with voltage filtering functions, for which a connection to an external capacitor is used. Coming from external quartz resonator In the Oscillator block, a signal (the nominal frequency of which is 24 MHz; lower frequency master oscillators were used for previous models of microcircuits) serves to synchronize all computational processes occurring inside the optical sensor chip. For example, the frequency of images of an optical sensor is tied to the frequency of this external generator (by the way, the latter is not subject to very strict restrictions on permissible deviations from the nominal frequency - up to +/- 1 MHz). Depending on the value entered at a specific address (register) of the chip’s memory, the following operating frequencies for taking pictures with the ADNS-3060 sensor are possible.

As you might guess, based on the data in the table, the frequency of sensor snapshots is determined using a simple formula: Frame rate = (Setting generator frequency (24 MHz)/Value of the register responsible for the frame rate).

Surface images (frames) taken by the ADNS-3060 sensor have a resolution of 30x30 and represent the same matrix of pixels, the color of each of which is encoded with 8 bits, i.e. one byte (corresponding to 256 shades of gray for each pixel). Thus, each frame (frame) arriving at the DSP processor is a sequence of 900 bytes of data. But the “cunning” processor does not process these 900 bytes of the frame immediately upon arrival; it waits until 1536 bytes of information about pixels are accumulated in the corresponding buffer (memory) (that is, information about another 2/3 of the subsequent frame is added). And only after this the chip begins to analyze information about the movement of the manipulator, by comparing changes in successive images of the surface.

With a resolution of 400 or 800 pixels per inch, their implementation is indicated in the RES bit of the microcontroller memory registers. A zero value of this bit corresponds to 400 cpi, and a logical one in RES sets the sensor to 800 cpi mode.

After the integrated DSP processor processes the image data, it calculates relative values displacement of the manipulator along the × and Y axes, entering specific data about this into the memory of the ADNS-3060 chip. In turn, the external controller (mouse) chip, via Serial Port, can “draw” this information from the memory of the optical sensor approximately once every millisecond. Note that only an external microcontroller can initiate the transfer of such data; the optical sensor itself never initiates such a transfer. Therefore, the issue of efficiency (frequency) of tracking mouse movement largely lies on the “shoulders” of the external controller chip. Data from the optical sensor is transmitted in 56-bit packets.

Well, the Led Control block with which the sensor is equipped is responsible for controlling the backlight diode - by changing the value of bit 6 (LED_MODE) at address 0x0a, the optosensor microprocessor can switch the LED to two operating modes: logical “0” corresponds to the “diode is always on” state, logical “1” puts the diode into the “on only when necessary” mode. This is important, say, when operating wireless mice, as it allows you to save the power of their autonomous power supplies. In addition, the diode itself can have several brightness modes.

This, in fact, is all about the basic principles of operation of an optical sensor. What else can you add? The recommended operating temperature of the ADNS-3060 chip, as well as all other chips of this kind, is from 0 0C to +40 0C. Although Agilent Technologies guarantees the preservation of the operating properties of its chips in the temperature range from -40 to +85 ° C.

Laser future?

Recently, the Internet was filled with praising articles about the Logitech MX1000 Laser Cordless Mouse, which used an infrared laser to illuminate the surface under the mouse. Almost a revolution in the field of optical mice was promised. Alas, having personally used this mouse, I was convinced that the revolution did not happen. But that's not what this is about.

I didn't understand Logitech mouse MX1000 (did not have the opportunity), but I am sure that behind the “new revolutionary laser technology” is our old friend - the ADNS-3060 sensor. Because, according to the information I have, the sensor characteristics of this mouse are no different from those of, say, the Logitech MX510 model. All the “hype” arose around the claim on the Logitech website that using a laser optical tracking system, twenty times (!) more details are detected than using LED technology. On this basis, even some respected sites have published photographs of certain surfaces, they say, how ordinary LED and laser mice see them :)

Of course, these photos (and thank you for that) were not the multi-colored bright flowers with which the Logitech website tried to convince us of the superiority of the laser illumination of the optical tracking system. No, of course, optical mice did not begin to “see” anything similar to the given color photographs with varying degrees of detail - the sensors still “photograph” nothing more than a square matrix of gray pixels, differing from each other only in different brightness (processing information about extended color palette of pixels would place an enormous burden on the DSP).

Let's estimate that to get a 20 times more detailed picture, you need, excuse the tautology, twenty times more details, which can only be conveyed by additional pixels of the image, and nothing else. It is known that the Logitech MX 1000 Laser Cordless Mouse takes pictures of 30x30 pixels and has a maximum resolution of 800 cpi. Consequently, there can be no talk of any twenty-fold increase in the detail of images. Where did the dog dig :), and aren’t such statements generally unfounded? Let's try to figure out what caused this kind of information to appear.

As is known, a laser emits a narrowly directed (with small divergence) beam of light. Consequently, the illumination of the surface under the mouse when using a laser is much better than when using an LED. A laser operating in the infrared range was chosen, probably, so as not to dazzle the eyes due to the possible reflection of light from under the mouse in the visible spectrum. The fact that the optical sensor works normally in the infrared range should not be surprising - from the red range of the spectrum, in which most LED optical mice operate, to the infrared - “at your fingertips”, and it is unlikely that the transition to a new optical range was difficult for the sensor. For example, the Logitech MediaPlay controller uses an LED, but also provides infrared illumination. Current sensors work without problems even with blue light (there are manipulators with such illumination), so the spectrum of the illumination area is not a problem for sensors. So, due to the stronger illumination of the surface under the mouse, we have the right to assume that the difference between the places that absorb radiation (dark) and reflect the rays (light) will be more significant than when using a conventional LED - i.e. the image will be more contrasty.

And indeed, if we look at real photographs of a surface taken by a conventional LED optical system and a system using a laser, we will see that the “laser” version is much more contrasty - the differences between the dark and bright areas of the image are more significant. Of course, this can significantly facilitate the work of the optical sensor and, perhaps, the future lies with mice with a laser backlight system. But such “laser” images can hardly be called twenty times more detailed. So this is another “newborn” myth.

What will the optical sensors of the near future be like? It's hard to say. They will probably switch to laser illumination, and there are already rumors on the Internet about a sensor being developed with a “resolution” of 1600 cpi. We can only wait.

The mouse perceives its movement in the working plane (usually on a section of the table surface) and transmits this information to the computer. A program running on a computer, in response to mouse movement, produces an action on the screen that corresponds to the direction and distance of this movement. In different interfaces (for example, in windowed ones), the user uses the mouse to control a special cursor - pointer - manipulator of interface elements. Sometimes entering commands with the mouse is used without the participation of visible elements of the program interface: by analyzing mouse movements. This method is called "mouse gestures" (eng. mouse gestures).

In addition to the motion sensor, the mouse has one or more buttons, as well as additional control parts (scroll wheels, potentiometers, joysticks, trackballs, keys, etc.), the action of which is usually associated with the current position of the cursor (or components of a specific interface) .

The mouse control components are in many ways the embodiment of the intentions of a chord keyboard (that is, a keyboard for touch operation). The mouse, originally created as a complement to the chord keyboard, actually replaced it.

Some mice have built-in additional independent devices - watches, calculators, phones.

Story

The first computer to include a mouse was the Xerox 8010 Star Information System minicomputer ( English), introduced in 1981. The Xerox mouse had three buttons and cost $400, which corresponds to approximately $930 in 2009 prices adjusted for inflation. In 1983, Apple released its own one-button mouse for the Lisa computer, the cost of which was reduced to $25. The mouse became widely known thanks to its use in Apple Macintosh computers and later in the Windows OS for IBM PC compatible computers.

Motion sensors

During the “evolution” of the computer mouse, the motion sensors have undergone the greatest changes.

Direct drive

The first computer mouse

The original design of the mouse motion sensor, invented by Douglas Engelbart at the Stanford Research Institute in 1963, consisted of two perpendicular wheels protruding from the body of the device. When moving, the mouse wheels rotated, each in its own dimension.

This design had many drawbacks and was soon replaced by a ball-drive mouse.

Ball drive

In a ball drive, the movement of the mouse is transmitted to a rubberized steel ball protruding from the body (its weight and rubber coating provide good grip on the working surface). Two rollers pressed against the ball record its movements along each of the measurements and transmit them to sensors that convert these movements into electrical signals.

The main disadvantage of the ball drive is contamination of the ball and the removal rollers, which leads to the mouse jamming and the need for periodic cleaning (this problem was partly mitigated by metallization of the rollers). Despite the disadvantages, the ball drive for a long time dominated, successfully competing with alternative sensor designs. Currently, ball mice have been almost completely replaced by second-generation optical mice.

There were two sensor options for the ball drive.

Contact sensors

The contact sensor is a textolite disk with radial metal tracks and three contacts pressed to it. The ball mouse inherited such a sensor from the direct drive.

The main disadvantages of contact sensors are oxidation of contacts, rapid wear and low accuracy. Therefore, over time, all mice switched to non-contact optocoupler sensors.

Optocoupler sensor

Mechanical computer mouse device

The optocoupler sensor consists of a double optocouplers- an LED and two photodiodes (usually infrared) and a disk with holes or ray-shaped slits that block the light flux as it rotates. When you move the mouse, the disk rotates, and a signal is taken from the photodiodes at a frequency corresponding to the speed of the mouse movement.

The second photodiode, shifted by a certain angle or having an offset system of holes/slits on the sensor disk, serves to determine the direction of rotation of the disk (light appears/disappears on it earlier or later than on the first one, depending on the direction of rotation).

First generation optical mice

Optical sensors are designed to directly monitor the movement of the working surface relative to the mouse. The elimination of the mechanical component ensured higher reliability and made it possible to increase the resolution of the detector.

The first generation of optical sensors was represented by various schemes of optocoupler sensors with indirect optical coupling - light-emitting and perceiving reflection from the working surface of photosensitive diodes. Such sensors had one common property - they required special shading (perpendicular or diamond-shaped lines) on the working surface (mouse pad). On some rugs, these shadings were done with paints that were invisible in normal light (such rugs could even have a pattern).

The disadvantages of such sensors are usually called:

• the need to use a special mat and the impossibility of replacing it with another. Among other things, the pads of different optical mice were often not interchangeable and were not produced separately;
• the need for a certain orientation of the mouse relative to the pad, otherwise the mouse would not work correctly;
• sensitivity of the mouse to dirt on the mat (after all, it comes into contact with the user’s hand) - the sensor was uncertain about shading on dirty areas of the mat;
• high cost of the device.

In the USSR, first-generation optical mice, as a rule, were found only in foreign specialized computing systems.

Optical LED Mice

Optical mouse

Second generation optical sensor chip

The second generation of optical mice has a more complex design. A special LED is installed at the bottom of the mouse, which illuminates the surface on which the mouse moves. A miniature camera “photographs” the surface more than a thousand times per second, transmitting this data to the processor, which draws conclusions about changes in coordinates. Second-generation optical mice have a huge advantage over the first: they do not require a special mouse pad and work on almost any surface except mirror or transparent ones; even on fluoroplastic (including black). They also do not require cleaning.

It was assumed that such mice would work on any surface, but it soon became clear that many sold models (especially the first widely sold devices) were not so indifferent to the patterns on the mouse pad. In some areas of the picture, the graphics processor can make significant errors, which leads to chaotic pointer movements that do not correspond to real movement. For mice prone to such failures, it is necessary to choose a rug with a different pattern or even with a single-color coating.

Some models are also prone to detecting small movements when the mouse is at rest, which is manifested by the pointer on the screen shaking, sometimes with a tendency to slide in one direction or another.

Dual sensor mouse

Second-generation sensors are gradually improving, and crash-prone mice are much less common these days. In addition to improving sensors, some models are equipped with two displacement sensors at once, which allows, by analyzing changes in two areas of the surface at once, to exclude possible mistakes. These mice are sometimes able to work on glass, plexiglass and mirror surfaces (which other mice do not work on).

There are also mouse pads specifically targeted at optical mice. For example, a rug that has a silicone film on the surface with a suspension of glitter (it is assumed that the optical sensor detects movements on such a surface much more clearly).

The disadvantage of this mouse is the difficulty of its simultaneous work with graphics tablets; the latter, due to their hardware features, sometimes lose the true direction of the signal when moving the pen and begin to distort the trajectory of the tool when drawing. No such deviations were observed when using mice with a ball drive. To eliminate this problem, it is recommended to use laser manipulators. Also, some people consider the disadvantages of optical mice to be that such mice glow even when the computer is turned off. Since most inexpensive optical mice have a translucent body, it allows red LED light to pass through, which can make it difficult to sleep if the computer is in the bedroom. This happens if the voltage to the PS/2 and USB ports is supplied from the standby voltage line; majority motherboards allow you to change this with a +5V jumper<->+5VSB, but in this case it will not be possible to turn on the computer from the keyboard.

Optical laser mice

Laser sensor

In recent years, a new, more advanced type of optical sensor has been developed that uses a semiconductor laser for illumination.

Little is known about the disadvantages of such sensors, but their advantages are known:

• higher reliability and resolution
• absence of noticeable glow (the sensor only needs weak laser illumination in the visible or, possibly, infrared range)
• low power consumption

Induction mice

Graphics tablet with induction mouse

Induction mice use a special pad that works like a graphics tablet or are included in the kit graphics tablet. Some tablets include a manipulator similar to a mouse with a glass crosshair, working on the same principle, but with a slightly different implementation, which makes it possible to achieve increased positioning accuracy by increasing the diameter of the sensitive coil and moving it out of the device into the user’s line of sight.

Induction mice have good accuracy and do not need to be oriented correctly. An induction mouse can be “wireless” (the tablet on which it operates is connected to the computer), and have induction power, therefore, do not require batteries, like conventional ones wireless mice.

The mouse included with the graphics tablet will save some space on the table (provided that the tablet is always on it).

Induction mice are rare, expensive and not always comfortable. It is almost impossible to change a mouse for a graphics tablet to another one (for example, one that better suits your hand, etc.).

Gyroscopic mice

In addition to vertical and horizontal scrolling, mouse joysticks can be used for alternative pointer movement or adjustments, similar to wheels.

Trackballs

Induction mice

Induction mice most often have induction power from a working platform (“mat”) or graphics tablet. But such mice are only partly wireless - the tablet or pad is still connected with a cable. Thus, the cable does not interfere with moving the mouse, but also does not allow you to work at a distance from the computer, as with a regular wireless mouse.

Additional functions

Some mouse manufacturers add functions to alert the mouse about any events occurring on the computer. In particular, Genius and Logitech release models that notify about the presence of unread emails V mailbox by lighting an LED or playing music through the mouse's built-in speaker.

There are known cases of placing a fan inside the mouse case to cool the user's hand while the user's hand is working with air flow through special holes. Some mouse models designed for computer gamers have small eccentrics built into the mouse body, which provide a vibration sensation when shooting computer games. Examples of such models are the Logitech iFeel Mouse line of mice.

In addition, there are mini mice designed for laptop owners that are small in size and weight.

Some wireless mice have the ability to work as a remote control (for example, Logitech MediaPlay). They have a slightly modified shape to work not only on the table, but also when held in the hand.

Advantages and disadvantages

The mouse has become the main point-and-point input device due to the following features:

• Very low price(compared to other devices like touch screens).
• The mouse is suitable for long-term use. In the early days of multimedia, filmmakers liked to show the computers of the “future” with a touch interface, but in reality this method of input is quite tedious, since you have to hold your hands in the air.
• High accuracy of cursor positioning. With the mouse (with the exception of some “unsuccessful” models) it is easy to hit the desired pixel on the screen.
• The mouse allows many different manipulations - double and triple clicks, dragging, gestures, pressing one button while dragging another, etc. Therefore, you can concentrate in one hand a large number of controls - multi-button mice allow you to control, for example, a browser without using the keyboard at all.

The disadvantages of the mouse are:

• Danger of carpal tunnel syndrome (not supported by clinical studies).
• For work, a flat, smooth surface of sufficient size is required (with the possible exception of gyroscopic mice).
• Instability to vibrations. For this reason, the mouse is practically not used in military devices. The trackball requires less space to operate and does not require moving your hand, cannot get lost, has greater resistance to external influences, and is more reliable.

Ways to grip a mouse

Players recognize three main ways to grip the mouse.

• With your fingers. The fingers lie flat on the buttons, the top of the palm rests on the “heel” of the mouse. The lower part of the palm is on the table. The advantage is precise mouse movements.
• Claw-shaped. The fingers are bent and only the tips touch the buttons. The “heel” of the mouse is in the center of the palm. The advantage is the convenience of clicks.
• Palm. The entire palm rests on the mouse, the “heel” of the mouse, as in a claw grip, rests against the center of the palm. The grip is more suitable for the sweeping movements of shooters.

Office mice (with the exception of small laptop mice) are usually equally suitable for all grip styles. Gaming mice, as a rule, are optimized for one grip or another - therefore, when buying an expensive mouse, it is recommended to find out your grip method.

Software support

A distinctive feature of mice as a class of devices is the good standardization of hardware

If at one time the user performed most of the actions only using the keyboard and this was considered normal, today it is very difficult to imagine home computer without a mouse. You don't have to go far. Just try to open your browser without a mouse and surf the Internet a little, you will quickly notice how inconvenient it is, no matter how many hotkeys the browser contains. And since each of us deals with a mouse almost every day, in this short article I will generally consider what a computer mouse is, what it consists of, what types there are and when it appeared.

I'll start with a definition. A computer mouse is an input device that converts data about movement along a plane into an information signal. It is also typical for a computer mouse to have at least one button (in Mac OS X, mice come with one button).

The mouse appeared back in 1968 and was patented in 1970. The mouse became included with the computer in 1981 as part of the Xerox-8010 Star Information.

The basic device of the mouse is a movement sensor and buttons, nothing fancy. However, additional controls such as a scroll wheel and trackball may also be present. In general, it all depends on the imagination of the manufacturers.

Basically, mice are divided according to the principle of constructing a motion sensor, and here they are:

1. Direct drive is the very first version of the sensor. These mice used two wheels at the bottom, for the horizontal and vertical axis.

2. Ball drive - the next option for constructing a displacement sensor. In this case, not wheels were used, but one ball, which is adjacent to small shafts inside the mouse itself. This mechanism made it more convenient to use the mouse, since the ball, unlike wheels, will never catch on the surface.

3. Optical drive- this sensor uses an optical mechanism to track the position of the mouse. There have been several generations of such sensors, the latest of which is an unpretentious laser mouse. As a fact, in the first variations special mats were required, since the sensors were very sensitive to the quality of the surface.

4. Gyroscopic mice - contain a gyroscope, which allows you to determine mouse movements even in three-dimensional space.

5. Induction mice - require a special mouse pad, since position determination is determined through induction processes.

If we talk about buttons, they are one-button, two-button and three-button. In this case, we are talking about the buttons that are located at the top and are the most massive (main). As already mentioned, each manufacturer can add controls to mice. For example, gaming mice can contain a dozen small side buttons, which significantly reduce the time for calling frequent operations. However, it is worth knowing that these additional buttons can only be used if the special software from the same manufacturers. Otherwise, operating system will ignore them.

Based on the type of connection, mice are:

1. Wired. Such mice used to be connected via COM ports and PS/2. Today, almost all mice use the USB interface.

2. Wireless infrared - a special IR signal receiver is connected to the computer. Such mice have taken root poorly, since there should be no obstacles between the receiver and the mouse.

3. Wireless with radio communication - these mice use radio communication as a mechanism for transmitting information. They quickly replaced IR mice due to the lack of problems with obstacles.

4. Wireless induction mice - these mice are used together with a special mouse pad. The good thing is that they do not need to be charged, they are powered directly from the mat. The downside is that without a mat they are useless.

5. Wireless with bluetooth - compared to analogues, these mice benefit from the fact that the computer only needs to have a bluetooth receiver. So it’s very easy to connect such a mouse to laptops and you don’t need to worry about a protruding receiver, an occupied USB slot and other things.

As you can see, the variety, although quite large, is still mainly related to the internal features and conditions of use. Therefore, if you need a mouse, then you need to soberly evaluate its real use. For example, cheap laser mice are the leaders for home computers.

To solve one of the problems, I needed to programmatically obtain and process images of a small area of ​​the paper surface from a very close distance. Not getting decent quality when using regular USB cameras and already halfway to the store for an electron microscope, I remembered one of the lectures in which we were told how various devices, including a computer mouse, work.

Preparation and a little theory

After googling information on this topic and disassembling an old PS/2 Logitech mouse, I saw a picture familiar from articles on the Internet.

Not good complex circuit“first generation mice”, an optical sensor in the center and a PS/2 interface chip slightly higher. The optical sensor I came across is an analogue of the “popular” models ADNS2610/ADNS2620/PAN3101. I think they and their counterparts were mass produced in the same Chinese factory, with different labels on the output. Documentation for it was very easy to find, even along with various code examples.

The documentation says that this sensor receives an image of a surface measuring 18x18 pixels (400cpi resolution) up to 1500 times per second, stores it and, using image comparison algorithms, calculates the offset in X and Y coordinates relative to the previous position.

Implementation

We connect 5V and GND to the corresponding Arduino outputs, and the sensor legs SDIO and SCLK to digital pins 8 and 9.

To obtain an offset by coordinates, you need to read the value of the chip register at addresses 0x02 (X) and 0x03 (Y), and to dump the picture you need to first write the value 0x2A at address 0x08, and then read it from there 18x18 times. This will be the last “remembered” value of the image brightness matrix from the optical sensor.

You can see how I implemented this on Arduino here: http://pastebin.com/YpRGbzAS (only ~100 lines of code).

And to receive and display the image, a program was written in Processing.

Result

You can notice the texture of the surface (paper) and even individual letters on it. It should be noted that such clear picture quality is obtained due to the fact that the developers of this mouse model added a special glass stand to the design with a small lens directly under the sensor.

If you start to lift the mouse above the surface even a couple of millimeters, the clarity immediately disappears.

If you suddenly want to repeat this at home, to find a mouse with a similar sensor, I recommend looking for old devices with a PS/2 interface.

Conclusion

I will leave links to materials that were very useful to me for solving this problem. It really wasn’t difficult and was done with great pleasure. Now I'm looking for information about the chips of more expensive models of modern mice to obtain high-quality images with higher resolution. I might even be able to build something like a microscope (the image quality from the current sensor is clearly not suitable for this). Thank you for your attention!