Is the joystick an information input device? Data input/output devices, their types and main characteristics

Ergonomic keyboards not only increase typist productivity and reduce overall fatigue during the workday, but also reduce the likelihood and severity of a number of diseases, such as carpal tunnel syndrome and osteochondrosis of the upper spine.

Mouse– manipulator-type control device.Moving the mouse on a flat surface is synchronized with the movement of a graphic object (mouse pointer) on the monitor screen.

Unlike the keyboard discussed earlier, the mouse is not a standard control, and the personal computer does not have a dedicated port for it. There is no permanent dedicated interrupt for the mouse, and the computer's basic input and output (BIOS) facilities, located in read-only memory (ROM), do not contain software to handle mouse interrupts.Due to this, the mouse does not work the first moment after turning on the computer. She needs special support system program– mouse drivers.The driver is installed either when you first connect the mouse, or when installing the computer's operating system.Although the mouse does not have a dedicated port on motherboard, to work with it, use one of the standard ports, tools for working with which are included in the BIOS.The mouse driver is designed to interpret the signals coming through the port. In addition, it provides a mechanism for communicating information about the position and state of the mouse to the operating system and running programs.The computer is controlled by moving the mouse along the plane and briefly pressing the right and left buttons (These presses are called clicks.)Unlike a keyboard, a mouse cannot be directly used to enter character information - its control principle is event-based.Mouse movements and button clicks are events from the point of view of its driver program.

A standard mouse has only two buttons, although there are custom mice with three buttons or two buttons and one rotary control.Recently, mice with a scroll wheel located between two buttons and allowing scrolling in any Windows application have become increasingly common.

In addition to a regular mouse, there are other types of manipulators, for example: trackballs, penmouses, infrared mice.The trackball, unlike a mouse, is installed stationary, and its ball is driven by the palm of the hand.

The advantage of a trackball is that it does not require a smooth working surface, which is why trackballs are widely used in portable personal computers.

Penmouse is an analogue of a ballpoint pen, at the end of which, instead of a writing unit, there is a unit that records the amount of movement.

For computer games and in some specialized simulators, lever-type manipulators (joysticks) and similar joypads, gamepads and steering-pedal devices are also used. Devices of this type are connected to a special port available on sound card, or to the USB port.

Touchpad(English touchpad - touch pad), touchpad- a pointing input device, most often used in laptops.

Touchpads are fairly low resolution devices. This allows you to use them in everyday work at the computer (office applications, web browsers, logic games), but makes it very difficult to work in graphic editors.

However, touchpads also have a number of advantages compared to other manipulators:

• do not require a flat surface (unlike a mouse);
• do not require a lot of space (unlike a mouse or graphics tablet); the location of the touchpad is fixed relative to the keyboard (unlike a mouse);
• To move the cursor across the entire screen, you only need to move your finger a little (unlike a mouse or a large graphics tablet);
• working with them does not require much getting used to, as is the case with a trackball, for example.

It is a lever on a stand that can be tilted in two planes.The lever may contain various types of triggers and switches.

Scanner– a device for inputting graphic images into a computer. A sheet of paper with an image is placed into the scanner. The device reads it and sends it to the computer in digital form. During scanning, a powerful lamp and a ruler with many photosensitive elements located on it in a row move smoothly along the sheet with the image. Typically, photodiodes are used as photosensitive elements. Each photosensitive element produces a signal proportional to the brightness of the reflected light from the section of paper located opposite it. The brightness of the reflected beam changes because the bright areas of the scanned image are much more reflective than the dark areas covered with paint. Color scanners have three groups of photosensitive elements that process red, green and blue colors, respectively. Thus, each point in the image is encoded as a combination of signals produced by photosensitive elements of the red, green and blue groups. The signal encoded in this way is transmitted to the scanner controller in the system unit.

Distinguish hand-held, pull-through and flatbed scanners. In hand-held scanners, the user himself guides the scanner along the surface of the image or text. Stretch scanners are designed to scan images on sheets of only a certain size. The pulling device of such scanners sequentially moves all sections of the scanned sheet over a stationary photosensitive matrix. The most widely used are flatbed scanners, which allow you to scan paper sheets, books and other objects containing images. Such scanners consist of a plastic case covered with a lid. The upper surface of the body is made of optically transparent material, on which the scanned image is placed. After this, the image is covered with a lid and scanning is performed. During the scanning process, a lamp with a light-sensitive matrix moves under the glass.

The main characteristics of scanners are reading speed, which is expressed by the number of pages scanned per minute (pages per minute - ppm), and resolution, expressed by the number of dots of the resulting image per inch of the original (dots per inch - dpi).

In modern tablets, the main working part is also a network of wires (or printed conductors), similar to the one in the Grafacons. This grid has a fairly large pitch (3-6 mm), but the mechanism for registering the position of the pen allows you to obtain a step for reading information much smaller than the grid pitch (up to 200 lines per mm).

There are different types of tablets based on their operating principle and technology. INelectrostatictablets register a local change in electrical n potential grids under the feather. INelectromagnetic- the pen emits electricity electromagnetic waves, and the grid serves as a receiver. In both cases, power must be supplied to the pen.

Wacom created technology based on electromagnetic resonance , when the grid both emits and receives a signal. In this case, the signal emitted by the grid is used to power the pen, which, in turn, sends a response signal, which is not just a reflection of the original one, but a newly formed one, which, as a rule, carries additional information, identifying a specific pen, as well as data on the pressure applied, the fixation/position of the controls on the pointer, and whether the working tip of the pen or its “eraser” is used (if such functions are provided in it). Therefore, no separate power supply is required for such a device. But when operating electromagnetic tablets, interference from emitting devices is possible, in particular monitors. Some are based on the same operating principle. touchpads.

There are tablets that come with pens that can register pressure. Typically, the registration mechanism is based on the use of variable capacitor. In particular, this type of sensor is used in pens for Wacom tablets. Registration can also be done using component with variable resistance or variable inductance . There are implementations based onpiezoelectric effect. When you press the pen within the working surface of the tablet, under which a grid of conductors is laid, a potential difference arises on the piezoelectric plate, which allows you to determine the coordinates of the desired point. Such tablets do not require a special pen at all and allow you to draw on the working surface of the tablet as on a regular drawing board.

In addition to pen coordinates, modern graphics tablets can also determine pressure pen on the working surface, tilt, direction of rotation in the plane of the tablet and the force of compression of the pen with your hand.

Also, a set of graphic tablets may include a mouse together with a pen, which, however, does not work like a regular one.computer mouse, but on the same principle as the pen. This mouse can only work on a tablet. Since the resolution of a tablet is much higher than the resolution of a conventional computer mouse, using a mouse + tablet combination allows you to achieve significantly higher accuracy when entering.

Graphic tablets are used both for creating images on a computer in a way that is as close as possible to how images are created on paper, and for general work with interfaces that do not require relative input (although entering relative movements using a tablet is possible, it is often inconvenient).

In addition, they are convenient to use for transferring (rendering) already ready-made images to the computer.

With technological progress, everything appears more devices, intended for entering data into a computer. The following article contains information about these devices.

Initially, the only way to enter information into computer memory was to type it by hand using a keyboard. However, as technology developed, newer and faster input devices began to be created. They help you enter significant amounts of information into your computer without having to long work manually. Tech-savvy users know computer input devices like the back of their hand, but if you still find it difficult to answer the question of what exactly can be called a computer input device, then this article will most fully answer your question.

What are computer input devices?

These are hardware components that help you put information into your computer's memory. A computer that does not have devices for inputting information or commands can only be used as a regular TV. Such devices help you not only store data in the computer’s memory, but also subsequently print it on a printer, send it to email, copy to portable devices. Therefore, any input device can be considered peripheral device, which helps you enter data and controls the commands your computer executes.

Input devices are divided into the following categories:
- audio, video and mechanical devices;
- continuous input devices (for example, a mouse, the position of which changes quite quickly and constantly, which can be considered as continuous input);
- devices for spatial use, such as a 2D mouse or 3D navigator (especially for CAD applications).

Also, many computer pointing input devices are classified according to the way they control the cursor:
- direct input, when control is carried out directly at the location where the cursor is visible. For example, touch panels and screens;
- indirect pointing devices, e.g. Trackballs or mice.

Species computer devices input

Now let's look at various devices that can help with information processing on a computer.

Keyboard is the oldest and most widely used input device. It is used with desktop computers, laptops and other types of computing devices. Computer keyboard contains all the most necessary alphabetic and numeric characters for entering data and commands. Most often, the keyboard is connected to the computer using a wire, but nowadays wireless keyboards.

Mouse- a small hand-held computer device that helps you navigate the screen and perform the necessary action. The computer mouse is displayed on the monitor as a cursor, which is used to open files, folders and allows you to select the desired menu items. A mouse, like a keyboard, is either connected to the computer via wires or has a wireless connection.

Graphic tablets . A graphics tablet uses pen-like input devices called styluses. With this device you can write on a tablet or touch screen as if you were using a regular pen. Some styluses have special buttons that allow you to use this device as a mouse. Many of the latest graphics tablets are designed to be used with your fingers instead of a stylus.

Joysticks. If you are an avid gamer and like to spend time playing computer games, then a joystick (or gamepad) will be the best assistant for you. This is a movable handle with a button or two that helps control the movements of the characters in the game. The latest generation of joysticks come with a variety of button modifications to allow you to perform many complex in-game moves with just the press of your finger.

Scanners- computer input devices that will help you create an electronic copy of a document or even a photograph. You can then copy digital image document you want to display and save it on your computer or print it. This copy can also be modified using graphics or text programs.

Headsets. This includes devices such as headphones and a microphone. They will help you record your voice, dictate data or even commands to your computer. Modern headsets leave your hands free to perform a variety of tasks. You can even install software for voice recognition so that the computer only accepts commands spoken in your voice.

Multimedia input devices . There are many various devices, which will help you exchange information in various formats with your computer. The following are devices designed to perform image digitization, video or audio processing functions:

Webcam
- graphic scanner
- digital cameras
- barcode reader
- fingerprint scanner
- 3D scanner
- laser meter
- hardware video recording
- MIDI keyboard

Listed above are some of the computer input devices that will help you transfer data to your computer from other devices. As technology grows, methods for converting information and entering data continue to improve. This article discussed those devices that are most often used by home users today.

Input device

Introduction

Input devices are those devices through which information can be entered into a computer. Their main purpose is to implement an impact on the machine. The variety of input devices produced has given rise to entire technologies from touch to voice. Although they work on different principles, they are intended to implement one task - to allow a person to communicate with a computer. Graphic information input devices are widely used due to the compactness and clarity of the way they present information to humans. Based on the degree of automation of the search and selection of image elements, graphic information input devices are divided into two large classes: automatic and semi-automatic. In semi-automatic graphic information input devices, the functions of searching and selecting image elements are assigned to a person, and the conversion of the coordinates of the read points is performed automatically. In semi-automatic devices, the process of searching and selecting image elements is carried out without human intervention. These devices are built either on the principle of scanning the entire image, followed by its processing and conversion from a raster representation to a vector one, or on the principle of line tracking, which ensures reading of graphic information presented in the form of graphs, diagrams, and contour images. The main areas of application of graphic information input devices are computer-aided design systems, image processing, training, process control, animation and many others. These devices include scanners, encoding tablets (digitizers), light pens, touch screens, digital cameras, video cameras, computer keyboards, mice, and others.

The Keyboard is designed to enter information from the user into the computer.

The keyboard, despite strong competition from the mouse, is the main input device. Its dominant position is unlikely to change until a reliable and inexpensive system for recognizing human speech is created.

Keyboard with plastic pins

Plastic and rubber are used to make such keyboards. Pressing a key on such a keyboard often feels exceptionally soft. If you don't look at the screen, you don't know whether a key is pressed or not. Another drawback of these keyboards is vibration, which causes the effect of a key opening repeatedly if it is pressed incorrectly. Thus, it can easily happen that when you press a key, the corresponding symbol is displayed on the screen several times. For a device that types touch-type or at high speed, this is an extremely undesirable side effect.

Clicky keyboard

The above phenomena do not exist in the clicky keyboard. When you press a key on such a keyboard, the mechanical resistance of the key increases the deeper it is pressed. To overcome this resistance you need to expend a certain force, after which the key moves very easily. This ensures unambiguous contact.

Pressing and releasing a key is accompanied by a click, hence the name. Clicky keyboards are preferred over non-clicky keyboards because they can be assured of a relatively clean keystroke.

To connect the keyboard, a cable about 1 m long is used, having a 5-pin DIN connector or a 6-pin Mini-DIN (PS/2).

The keyboard is one of critical devices, which determines the conditions for comfortable work on the PC. The main element of a keyboard is the keys. When purchasing a keyboard, you should test it thoroughly to determine whether the keyboard's mechanics suit your individual needs. It almost doesn't matter what materials are used for the keyboard case and keys. It can be either plastic or metal. Color and other aspects are not as important from a functional point of view as the keyboard mechanics used.

Along with the keyboard, the mouse is the most important means of entering information into the computer. The mouse is a small box with several buttons that easily fits in the palm of your hand. Mice are usually produced with two or three buttons, but special models have more than three buttons (for example, Internet mouse). Together with a wire for connecting to a computer, this device really resembles a mouse with a tail. Some application programs are designed to work only with a mouse, but allow the mouse to be replaced by commands entered from the keyboard.

For optimal functioning, the mouse must move on a flat surface - special mouse pads are usually used.

Optical-mechanical mouse

Despite the name, this is a very ordinary mouse. The movements of the rubber-coated metal ball contained inside are recorded by two plastic rollers located at right angles to each other (X and Y axis). These rollers have a disk with raster holes at the end (similar to a wheel with spokes). When you move the mouse across the mousepad, the ball sets in motion the rollers with disks in contact with it. Each disk is located between the light source and the photosensitive element, which, in the order in which the photosensitive elements are illuminated, determine the direction and speed of the mouse's movement.

Optical mouse

An optical mouse works on principles similar to the operation of an optical-mechanical mouse, only the movement of the mouse is not recorded by mechanical rollers. An optical mouse sends a beam to a special mousepad. This beam, after being reflected from the mat, enters the mouse and is analyzed by electronics, which, depending on the type of signal received, determines the direction of movement of the mouse, based either on the angles of incidence of the light or on a special backlight. The advantage of such a mouse is reliability and reliability. Reducing the number of mechanical components leads to an increase in its service life.

Infrared mice

The godfathers of the infrared mouse were televisions, VCRs, etc. remote control. An infrared radiation receiver is installed next to or on the computer, which is connected to the PC by cable. Mouse movement is detected using already known mechanics and converted into an infrared signal, which is then transmitted to the receiver. The advantage of free movement is somewhat reduced by the inherent disadvantage. For flawless transmission of the infrared signal, “eye” contact must always be established between the receiver and transmitter. You cannot block the emitter of such a mouse with books, heat-absorbing or other materials, since with low signal power the mouse will not be able to transmit the signal to the PC. Infrared mice are equipped with a battery or regular battery.

Radio mouse

A more interesting alternative is to transmit information from the mouse via a radio signal. In this case, there is no need for eye contact between the receiver and the transmitter. The operation of such mice may be disrupted by external interference.

Based on the principle of operation, a Trackball can best be compared to a mouse that lies on the table with its belly up.

There are two main ways to connect mice (wired): through a serial port - a 9-pin Sub-D connector and through a 6-pin PS/2 connector.

A scanner is an automatic graphic information input device. There are several types of scanners, differing in the way the reading mechanism (its head) and the original move relative to each other: manual, roll, flatbed, projection and drum.

A handheld scanner is the simplest type of scanner. Here, the role of the drive of the reading mechanism is performed by the human hand, and the nature of the work of this type of scanner is somewhat reminiscent of a mouse. Obviously, how evenly the user moves the scanner depends on the degree of distortion of the image transmitted to the computer. The main advantages of this type of scanners include small overall dimensions and relatively low price, while the disadvantages arise from the design principle. Using such scanners, it is impossible to enter an A4 format image in one pass, since the reading head is small in size (standard width is 105 mm). Modern hand-held scanners can provide automatic “gluing” of images, that is, they form a whole image from separately entered parts. In general, it is very difficult to achieve high image quality with their help, so hand-held scanners can be used for a limited range of tasks. In addition, they are completely devoid of the “intelligence” inherent in other types of scanners.

In roll scanners, the scanning head stands still, and the paper moves relative to it using a feeding mechanism (as in a dot-matrix printer). The main advantage - at a relatively low price of the scanner - is the ability to input documents in A4 format. However, you can scan a book only after first dividing it into separate sheets.

Flatbed (the most common type) scanners, in which the scanning head moves relative to the paper using a stepper motor, do not have this drawback. Originally used for scanning opaque originals. Almost all models have a removable cover, which allows you to scan “thick” originals (magazines, books). Additionally, some models can be equipped with a feed mechanism separate sheets. Recently, many leading companies in the production of flatbed scanners have begun to additionally offer a slide module (for scanning transparent originals). The slide module has its own light source located on top. This slide module is installed on a flatbed scanner instead of a simple cover and turns it into a universal one.

In projection scanners, the reading part moves using a micromechanism. Their appearance resembles a photographic enlarger. Some of these scanners do not use a special light source; natural light is sufficient. Although projection scanners provide high-resolution and high-quality scanning of small format slides (usually no larger than 4 by 5 inches in size), documents, books, adding the ability to enter projections of three-dimensional objects into a computer, they have a significant drawback - low scanning speed. There are two modifications: with a horizontal and vertical arrangement of the optical reading axis.

The main difference between drum scanners is that the original is fixed on a transparent drum, which rotates at high speed. The reading element is located as close as possible to the original. This design provides the highest scanning quality. Typically, three photomultiplier tubes are installed in drum scanners, and scanning is carried out in one pass. In order to reduce the cost, “younger” models from some companies use a photodiode as a reading element instead of a photomultiplier. Drum scanners are capable of scanning opaque and transparent at the same time.

There are only two types of originals: transparent (negative and positive slides), which are scanned in transmitted light, and opaque, scanned in reflected light. Opaque originals are either analogue images - photographs, or discrete ones - illustrations from printed publications.

In addition, information input devices include:

JOYSTICK - (eng. Joystick = Joy + Stick) - a control device in computer games. It is a lever on a stand that can be tilted in two planes. The lever may contain various types of triggers and switches. The word “joystick” is also commonly used to refer to a control lever, for example, in a mobile phone.

In Russian, the control handle of industrial mechanisms and vehicles (airplanes, etc.) is never called a joystick (unlike the English joystick).

LIGHT PEN - (English lightpen, also - stylus, English stylus) - one of the tools for entering graphic data into a computer, a type of manipulator.

Externally, it looks like a ballpoint pen or pencil connected by a wire to one of the computer’s I/O ports. Typically, a light pen has one or more buttons that can be pressed by the hand holding the pen. Inputting data using a light pen involves touching or drawing lines with the pen on the surface of the monitor screen. A photocell is installed in the tip of the pen, which registers the change in screen brightness at the point with which the pen comes into contact, due to which the corresponding software calculates the position “indicated” by the pen on the screen and can, depending on the need, interpret it in one way or another, usually as a reference to an object displayed on the screen or as a drawing command. The buttons are used similarly to the buttons of a Mouse-type manipulator - to perform additional operations and enable additional modes.

The light pen was common during the proliferation of EGA graphics cards, which usually had a connector for connecting a light pen. The light pen cannot be used with regular LCD monitors.

DIGITIZER (with a light pen) - A graphics tablet (or digitizer, digitizer, from the English digitizer) is a device for entering handwritten drawings directly into a computer. Consists of a pen and a flat tablet that is sensitive to pressure or proximity of the pen.

Main user characteristics:

Working area - The working area is usually equal to one of the standard paper formats (A7-A0). The cost is approximately proportional to the area of ​​the tablet. It is more convenient to work on large tablets.

Resolution - The resolution of the tablet is the step at which information is read. Resolution is measured in dots per inch (dpi). Typical resolution values ​​for modern tablets are several thousand dpi.

Degrees of Freedom - Degrees of freedom describes the number of quasi-continuous characteristics of the relative position of the tablet and pen.

The minimum number of degrees of freedom is 2 (X and Y positions of the projection of the sensitive center of the pen), additional degrees of freedom may include pressure, tilt of the pen relative to the plane of the tablet.

TOUCHPAD (English touchpad - touch pad), touch panel - a pointing input device, used most often in laptops.

Operating principle. The operation of touchpads is based on measuring the capacitance of the finger or measuring the capacitance between the sensors. Capacitive sensors are located along the vertical and horizontal axes of the touchpad, which allows you to determine the position of your finger with the required accuracy.

Since the device operates by measuring capacitance, the touchpad will not work if you move a non-conductive object, such as the base of a pencil, over it. If you use conductive objects, the touchpad will only work if there is sufficient contact area. (Try touching the touchpad with your finger only slightly.) Wet fingers make the touchpad difficult to operate.

TOUCH SCREEN - designed to control devices by simply touching the screen. Touch screens have proven to be the most convenient way for humans to interact with machines. The use of touch screens has a number of advantages that are not available when using any other input devices: increased reliability, resistance to harsh external influences (including vandalism), and an intuitive interface.

Touch screens are used in payment terminals, information kiosks, trade automation equipment, pocket computers, operator panels in industry.

Operating principle. The touch screen is a glass structure placed on the surface of the display that displays the navigation system. The required system function is selected by touching the corresponding image on the screen. Controller touch screen processes the coordinates of the touch point and transmits them to the computer. Special software starts the selected function.

External devices (ED) are the most important component of any computing complex, they make up 50-80% of all PCs. The possibility and effectiveness of using PCs largely depend on the composition and characteristics of the VC.

External devices ensure the interaction of the computer with the environment: users, control objects and other computers. External devices are very diverse and can be classified according to a number of characteristics. The computer's computer includes external storage, input, output, input-output, teleprocessing and data preparation.

Thus, according to purpose, the following types of devices can be distinguished:

• external storage devices (ESD), or external memory PC;
• user dialog tools;
• information input devices;
• information output devices;
• means of communication and telecommunications.

Dialogue tools user devices include video monitors (displays), less often remote control typewriters (printers with keyboards) and speech input/output devices.

Video monitor (display) is a device for displaying information input and output from a PC. Displays are available in color and monochrome. They have different diagonal sizes.

Any text or graphic image on the screen of a computer monitor (as well as a TV) consists of many discrete elements, which represent a minimal element of the image (raster) and are called pixels. The number of dots on the screen from which an image is formed is called resolution, or resolution.

To form a raster (Fig. 2.5), the monitor uses special signals. During the scanning cycle, the beam moves along a zigzag path from the upper left corner to the lower right corner.

The clarity of the image on the monitor screen is significantly influenced by the size of the dot (grain or pixel) of the screen. The smaller the dot size (grain), the sharper the image. On standard size 640 x 480 monitors, a satisfactory image is obtained with a grain size of 0.39 mm, and a good image is obtained with a grain size of 0.31 mm. On monitors with large grain, the image appears fuzzy (blurry). At a resolution of 800 x 600, a grain size of 0.31 mm is required, and for the 1024 x 768 mode - 0.28 or 0.25 mm; The highest quality known monitor has a grain size of 0.19 mm.

There are two main technologies for producing displays - kinescopes (cathode ray tubes) and liquid crystal screens. CRTs work with analog and

Rice. 2.5.

multi-frequency monitors. Cathode ray tube displays have a serious drawback - high power consumption. Liquid crystal displays are very economical.

In liquid crystal displays, the screen consists of two glass plates, between which there are liquid crystals, which can change their optical structure and properties depending on the electrical charge, i.e. the crystals, under the influence of an electric field, change their orientation and thereby reflect light differently . The resolution of the liquid crystal display is 800 x 600 and 1024 x 768.

The computer's video card (video adapter) must also be considered integral to the monitor. It works as an intermediary between the processor and the monitor.

To devices entering information include:

• keyboard - a device for manually entering numerical, text and control information into a PC;
• manipulators(pointing devices): joystick; mouse, trackball; light pen, etc. - for entering graphic information onto the display screen by controlling the movement of the cursor across the screen, followed by encoding the cursor coordinates and entering them into the PC;
• scanners - for automatic reading from paper media and entering typewritten texts, graphs, pictures, drawings into a PC;
• graphics tablets(digitizers) - for manually entering graphic information and images by moving a special pointer (pen) across the tablet; when you move the pen, the coordinates of its location are automatically read and these coordinates are entered into the PC;

The keyboard consists of miniature switches assembled in a certain order. The microprocessor built into the keyboard monitors the state of these switches and, when each key is pressed or released, sends a corresponding message (interrupt) to the computer, and the computer programs (operating system) process these messages.

Computers use different types of keyboards. The most common is the universal keyboard (the so-called 101-key), sometimes used with minor modifications on most modern desktop computers (Fig. 2.6). Its keys represent letters from one or two natural languages, ten numbers, symbols used in program texts, and control keys.

To work with many modern programs, it is almost mandatory to use a mouse or other device that replaces it. When you move the mouse across a table or other surface on the computer screen, the mouse pointer (usually an arrow) moves accordingly.

The classic mouse had a mechanical device; the movement of the cursor depended on a rolling ball. There are other options on the market now: optical the mouse sends a beam to a special mat, which, after being reflected from the mat, enters the mouse and is analyzed by electronics; V infrared mouse movement is recorded mechanically and converted into an infrared signal; V radio- mice transmit information via radio signals. Regardless of the way this device is implemented, the principle of its operation is always the same: when it is necessary to perform this or that action (for example,

Rice. 2.6.

complete the menu item on which the mouse pointer is positioned), the user presses a particular button.

A scanner is a device that allows you to enter text, drawings, slides, photographs, etc. into a computer in graphic form. There are several classifications of scanners, but all such devices have:

• light sources;
• a mechanism for moving the sensor (or a system of deflecting mirrors) along the original or moving the original relative to the sensor;
• electronic device(to convert the read information into digital form).

Based on the method of moving the scanner's reading head and paper relative to each other, scanners are divided into two groups: hand-held and desktop.

Manual scanning is carried out by sequentially moving the scanner relative to the original. The advantages of such a scanner include low cost, small size, and wide selection of originals. The disadvantages are the inconsistent speed of the scanner relative to the original, which causes distortion of the scanned image, and limited possibilities for use in conjunction with recognition programs.

Desktop scanners come in flatbed, roller, drum and projector types. The main distinguishing feature of a flatbed scanner is that the scanning head moves relative to the paper using a stepper motor. This scanner is simple and easy to use, but has large dimensions.

In a roller scanner, the original is passed through the rollers of the paper feed mechanism and falls into the field of view of a line of sensors. The scanner operates in two modes: scan mode and fax mode. It is compact, can function automatically, and has a low cost. Disadvantages include the difficulty of aligning originals, a limited range of original types, inconvenience of working with sheets of different sizes, and the possibility of damage to the original.

Drum scanners, as the name implies, have a drum in the form of a transparent cylinder made of organic glass, on the surface of which the original is fixed. Nearby scanning sensors read the image. Scanning is performed with the highest resolution from an original of almost any type, but drum scanners are large and expensive. In addition, they cannot directly scan books and magazines.

Projection scanners resemble a photographic enlarger or projection machine. The advantages of such a scanner include: ease of alignment of the original; small footprint; a variety of scanned originals (including three-dimensional); the ability to combine flat and three-dimensional originals. Disadvantages are dependence on an external lighting source; restrictions on the size of the original; difficulty in arranging non-standard originals (for example: unfolded books).

To devices information output include printers and plotters (plotters).

Printers are printing devices for recording information on paper. Printers are divided into:

• color and monochrome;
• percussive and unaccented.

Impact printers include dot matrix printers. Dot matrix printers form an image using special print head needles. Matrix printers are unpretentious, reliable, easy to operate and have a long working life. They remain the undisputed leader in the implementation of such functions as obtaining several copies of a document at once (using carbon paper). The lifetime of the print head is about 700 million characters. The printing speed of dot matrix printers lies within a very wide range of 200-1400 characters/min. However, today it is insufficient. In addition, the dot matrix printer has a high noise level. This, as well as the relatively high price, render the described printing method obsolete.

Features of an inkjet printer include: low level noise, dependence of speed on print quality, inability to use paper on a roll. Inkjet print heads end in microscopic holes, or nozzles, through which ink is applied to the paper. The number of nozzles can vary from tens to several hundred.

Print speed inkjet printers lies in the range of 2-4.5 ppm for text (about 200 characters per second) and 0.3-1.5 ppm for graphics. The maximum value of printed pages per minute is up to seven.

Despite strong competition from inkjet printers, laser printers currently offer more high quality print. Most laser printer manufacturers use the same printing mechanism as copiers. The printing speed of a laser printer is determined by two factors: mechanical paper feeding and data processing speed. Usually laser printer equipped with its own processor. Since a laser printer is a page printer (i.e. it forms for printing full page), printing speed is measured in pages per minute. The average laser printer prints 4, at best 8 pages per minute. High-speed printers, which are typically used in computer networks, can print up to 20 or more pages per minute.

To obtain a color image with a quality close to a photograph, or to make pre-press color proofs, thermal printers are used, or, as they are also called, high-end color printers. Currently, three technologies for color thermal printing have become widespread: inkjet transfer of molten dye (thermoplastic printing); contact transfer of molten dye (thermal wax printing); thermal dye transfer (sublimation printing).

Plotters are used to output graphic information (graphs, drawings, drawings) from a PC onto paper. Plotters are an output device that is used only in special areas. They are usually used in conjunction with computer-aided design programs. The result of almost any such program is a set of design and/or technological documentation, a significant part of which consists of graphic materials. Thus, the plotter is based on drawings, diagrams, graphs, diagrams, etc. For this, the plotter is equipped with special auxiliary tools.

All modern plotters by design can be classified into two large classes:

• 1) tablets for the AZ-A2 format (less often A1 - AO);
• 2) drum (roll) plotters with a paper width of A1 or AO format; they use rolls of paper up to several tens of meters long and allow you to create long drawings and drawings.

There are vector plotters with drawing images using a pen and raster plotters: thermographic, electrostatic, inkjet and laser.

Most plotters have a pen-type writing unit. Special markers are used with the ability to automatically replace them (at a signal from the program) from the available set. In addition to felt-tip pens, ink pens, ballpoint pens, rapidographs, cabirafes and many other devices are used that provide different line widths, saturation, color palette, etc.

Recently, cutting plotters have been created based on pen plotters. The writing unit in such plotters is replaced by a cutter. The image is not transferred to paper, but, for example, to self-adhesive film or similar media. Letters or characters produced using a cutting plotter can be seen on shop windows, signs, signs, etc.

Communication and telecommunication devices are used for communication with devices and other automation equipment (interface adapters, adapters, digital-to-analog and analog-to-digital converters, etc.) and for connecting PCs to communication channels, to other computers and computer networks (network interface cards, “joints”) ", data transmission multiplexers, modems).

Multimedia is a set of hardware and software that allows a person to communicate with a computer using a variety of natural media: sound, video, graphics, texts, animation, etc.

Multimedia is used to create virtual reality, an interactive mode, when the user becomes not a passive observer of events, but an active participant. This applies not only to computer games, but also to other special software. In addition, multimedia-equipped PCs can create and process dynamic images in real time. The multimedia product must provide:

• acoustic effects of Sh-Bts quality
• visual dynamic and 3D effects;
• interaction with the user in such a way that acoustic and visual effects were combined with each other at his request.

Fast-growing media include speech input/output devices. These are microphone speaker systems(for example, "sound mice", the software of which allows you to recognize letters and words spoken by a person, identify them and encode them) and sound synthesizers, which convert digital codes into letters and words reproduced through loudspeakers (speakers) or sound speakers connected to a computer .

Security questions

• 1. The structure of a computer according to von Neumann and its differences from the modern organization of a PC.
• 2. Personal computer devices located inside the system unit.
• 3. Purpose and composition of the microprocessor.
• 4. Computer storage devices: classification, functions, main characteristics.
• 5. Types internal memory PC.
• 6. Magnetic external storage devices. Classification of magnetic disks.
• 7. Classification of optical storage devices.
• 8. Magneto-optical disks and flash memory.
• 9. Types of information input/output devices.
• 10. Monitor. Purpose, composition, modes and operating principle of the monitor.
• 11. Input devices: keyboard and mouse.
• 12. Purpose of the scanner. Classification and general characteristics scanners.
• 13. Classification of printers based on the principle of applying an image to paper.
• 14. Purpose and classification of plotters.

Purpose: entering alphanumeric characters, cursor control.

A cursor is a special icon on the display screen (dash, arrow, highlighted rectangle, cross, etc.) that marks the place where a character entered from the keyboard will appear, or the designation of a command (program, document) that needs to be executed.

Operating principle. The keyboard keys are connected to a pin matrix. Each key or key combination is assigned its own number (code). There is a separate microprocessor inside the keyboard. Each press of a key closes a contact. In this case, in accordance with the contact matrix, the microprocessor generates a code for the pressed key. This code is stored in a special area (microprocessor buffer) and becomes available for processing by software.

Keyboards come in mechanical, semi-mechanical and membrane types. Some keyboards make a mechanical click when you press a key, while others are silent.

the number of times each key is pressed until it fails,

Mouse manipulator

Purpose: control of the mouse cursor (pointer), input of control information.

With the advent of graphical shells, the mouse became necessary for efficient work on the computer.

Operating principle. A mouse is a small box with buttons. It contains a ball rolling on the surface of the table. Two mutually perpendicular rollers are pressed against the ball, which it rotates. The roller rotation sensors transmit signals to the computer. The “tail” of wires through which signals travel gives the device the name “mouse.” The mouse cursor is controlled by moving the mouse across the table. Control information is entered by clicking the mouse buttons.

Mice come in one-, two-, and three-button types. They can be connected to the computer by wire or using radio transmitters (wireless). There are optical mice without a ball, equipped with photocells, and optomechanical mice. A type of mouse can be considered a trackball, which can be compared to a mouse that lies on its back with its spherical belly up.

Main user characteristics:

number of button presses until it fails;

reaction to hand movement or ballistic effect;

resolution step (resolution);

design and ease of use (ergonomics).

Resolution is measured in dpi (dot per inch - dots per inch). If a mouse has a resolution of 900 dpi and is moved 1 inch (2.53 cm) to the right, then the mouse drive receives information through the microcontroller about a shift of 900 units to the right. Normal mouse resolution is from 200 to 900 dpi.

The ballistic effect is the dependence of the accuracy of mouse positioning on the speed of its movement.

Software support. The mouse driver is supplied with the device. Modern operating systems contain drivers for most manipulators of this type and automatically select the most suitable one when you turn on the computer.

Touchpad (English touchpad - touch pad), touch panel

A pointing input device, most often used in laptops.

Like other pointing devices, a touchpad is typically used to control the "pointer" by moving your finger across the surface of the device. Touchpads come in different sizes, but usually their area does not exceed 50 cm².

The operation of touchpads is based on measuring the capacitance of the finger or measuring the capacitance between the sensors. Capacitive sensors are located along the vertical and horizontal axes of the touchpad, which allows you to determine the position of your finger with the required accuracy.

Since the device operates by measuring capacitance, the touchpad will not work if you move a non-conductive object, such as the base of a pencil, over it. If you use conductive objects, the touchpad will only work if there is sufficient contact area. (Try touching the touchpad with your finger only slightly.) Wet fingers make the touchpad difficult to operate.

Trackball

A pointing device for entering relative motion information for a computer. Similar to a mouse in terms of operation and functions. The trackball is functionally an inverted mechanical (ball) mouse. The ball is located on the top or side and the user can rotate it with the palm or fingers without moving the body of the device. Despite the external differences, the trackball and the mouse are structurally similar - when moving, the ball rotates a pair of rollers or, in a more modern version, it is scanned by optical motion sensors (as in an optical mouse).

Currently, trackballs are rarely used in home and office computers, but they have found application in industrial and military computers, where the user has to work in conditions of limited space and vibration. Thus, trackballs are used in the control cabins of the S-300 missile system.

Joystick (eng. Joystick = Joy + Stick)

Device for inputting information into an electronic device, manipulator, part of the user interface. Used to change the position of an interface element (in particular, the cursor), as well as to iterate through list elements. Is one of standard means input for computers and many mobile phones. Widely used in computer games. It is a lever on the base that can be moved in one, two, or three planes. The lever usually contains buttons and switches for various purposes.

According to the number of degrees of freedom and, accordingly, planes in which the position of the controlled object can be changed, joysticks are divided into:

one-dimensional (control of object movement either up-down or left-right)

two-dimensional (object control in two planes)

three-dimensional (object control in all three planes)

Graphics tablet (or digitizer)

This is a device for entering handwritten drawings directly into a computer. Consists of a pen and a flat tablet that is sensitive to pressure or proximity of the pen. A special mouse may also be included. Graphics tablets are used both for creating images on a computer in a way that is as close as possible to how images are created on paper, and for general work with interfaces that do not require relative input (although entering relative movements using a tablet is possible , it is often inconvenient).

In addition, they are convenient to use for transferring (rendering) ready-made images to a computer.

Scanner

A device that, by analyzing an object (usually an image, text), creates a digital copy of the object’s image. The process of obtaining this copy is called scanning.

Purpose. A scanner is a device for converting graphic information into digital information. The function of a scanner is to obtain an electronic copy of a document created on paper.

Entering data into a computer is one of the most tedious and error-prone tasks, scanners make this job easier.

Operating principle. The lamp illuminates the scanned text, the reflected rays fall on a photocell consisting of many photosensitive cells. Each of them, under the influence of light, acquires electric charge. The analog-to-digital converter assigns a numerical value to each cell, and this data is transmitted to the computer.

Scanners can be hand-held, portable-page, flatbed-office, network (high-speed), large-format; they can be black and white (up to 64 shades of gray) and color (256 - 16 million colors).

Hand-held scanners look like a large “mouse” that the user moves over the scanned image. However, manual movement of the device along the paper and the small size of the scanned area do not provide sufficient speed and require careful joining of individual sections of the image. hand scanner

Desktop scanners include flatbed, roller (portable page), drum and projection scanners.

The main distinguishing feature of a flatbed scanner is that the scanning head moves relative to the stationary paper. They are simple and easy to use, allowing you to scan images both from individual sheets and from books and magazines.

With handheld page scanners, the paper moves relative to the scanning head. They are quite compact, but it is unlikely that you can scan a drawing from a book with them. This type of scanner is used to input document pages in formats from business cards to A4; the automatic paper feeding system ensures uniform scanning across the entire width of the sheet.

Main user characteristics:

resolution (optical resolution), that is, the number of recognizable dots (pixels) per inch (measured in dpi - dots per inch). Typically 600-1200 dpi;

scanning speed - an indicator of performance, which is equal to the time spent processing one line of the image;

dimensions of the sheet being scanned (scanning area);

bit depth - determines the maximum number of colors or shades of gray that the scanner can perceive.

Webcam

A digital video or photo camera capable of capturing images in real time, intended for further transmission over the Internet (in programs such as Instant Messenger or in any other video application).

Besides their obvious use in video conferencing, webcams quickly gained popularity as a means of allowing some Internet users to view the world through cameras connected to the Internet by other users.

There are cameras that broadcast via the Internet images of bird nests, city streets, private homes, countryside, offices, city panoramas, erupting volcanoes, cable cars, bakeries, etc. Today, there are web cameras even in space (for example, on International Space Station).

Digital camera

A device that is a type of camera in which the photosensitive material is a matrix or several matrices, consisting of individual pixels, the signal from which is represented, processed and stored in the camera itself in digital form.

Digital cameras can be divided into several classes:

Compact (“soap dish” of traditional sizes). Characterized by small size and weight. The small physical size of the matrix means low sensitivity or high noise levels. Also, this type of camera is usually characterized by the absence or insufficient flexibility manual settings exposition.

Ultra-compact, miniature. They differ not only in size, but often in the absence of a viewfinder and screen.

Built into other devices. They are distinguished by the absence of their own controls.

Pseudomirror - appearance resemble a SLR camera, and, as a rule, in addition to a digital display, are equipped with an eye viewfinder. The image in the viewfinder of such a device is formed on a separate digital screen, or on a rotating main screen. As a rule, they have a thread on the lens for attaching attachments and filters (for example, Konica Minolta series Z models).

Half-mirror is a slang term that describes a class of devices in which there is a focus on frosted glass through a shooting lens, but there is no way to change the lens. In such devices, the optical circuit contains a beam splitting prism, which directs from 10 to 50% of the light flux to the ground glass, and the rest is transmitted to the matrix. (examples - Olympus E-10, E-20)

Audio input device

Microphone (from micro- and phōnē - sound) is an electro-acoustic device that converts sound vibrations into vibrations electric current. Connects to the microphone input on the sound card. The sound card converts the electrical signal from the microphone into a digital discrete signal.