Every day, sitting down at his workplace in the office, a person takes a mouse in one hand and begins to perform his duties. He knows why he needs a keyboard, a printer, a scanner, but he does not even imagine that they have their own official name. All this - and the output of information.
How it works
All devices in a personal computer are controlled by a central processing unit. To ensure interaction with it, the output and input devices make requests to the logic element of the motherboard. It serves to provide communication and processing requests from external devices to the north bridge or the central processor if there is no bridge.
In general, computer science deals with the study of the structure of a personal computer. It defines input and output devices as the components of a typical personal computer that provide the user with the computer. But before proceeding with the description of all devices, the basic I / O device deserves special mention. It's also BIOS. This chip on the motherboard of a personal computer provides an initial check of all connected devices and starts the operating system.
Classification
Personal computer input and output devices can be classified in different ways. The determining factor for this will be their functional responsibilities.
The first item is the main input-output devices. In fact, only one item could be specified here - the keyboard, since without it, not a single user computer will continue to boot. You can turn off the monitor and mouse completely, but the computer will not work without a keyboard. The exception is server computers that work without external devices connected at all. So, the main input / output devices, without which a normal user will not be able to work, are:
- keyboard;
- monitor;
- mouse.
You can also select additional I / O devices:
- printers;
- scanners;
- joystick;
- projector;
- I/O devices also include sound devices.
This is not a complete list of possible devices that interact with the user, it is possible to list them for a very long time. Therefore, let's look at the input / output devices of the computer in more detail.
Monitors
Computer monitors have undergone many changes throughout their history. Starting from the old ones using a cathode ray tube, and ending with modern LCDs.
The monitor or display itself is a device that serves to output to the end user. They can be divided according to several criteria.
1. By type of information.
- Alphanumeric. These displays are designed to display textual information only.
- Graphic. We encounter these monitors every day, sitting down at a personal computer. They are intended to present information in graphical form, including video.
2. By screen type.
- on the basis of such you may have worked in 2000.
- LCD is a liquid crystal "flat" display, which is now used everywhere. This type of monitor is also used in laptops.
- Plasma.
- Laser - has not yet entered mass production.
Keyboards
What can be said about keyboards? The fantasy of manufacturers in this area has stepped far forward, and a sense of humor pushes for the most daring experiments.
Among the keyboards, you can find minimalistic options - without a side additional panel with numbers, and huge gaming keyboards with built-in joysticks, additional buttons and speakers. There are keyboards with an additional USB-connector and pink keyboards with "incomprehensible buttons" for "blondes". There are also silicone keyboards that roll up to make them easier to carry around, or simply fold up three times.
If you are going to buy a keyboard for yourself, just go to a computer store and choose the one that suits your taste.
mouse
Computer mice are such computer input / output devices, without which the work of an ordinary user is impossible. If an advanced user can navigate through folders and files, as well as some programs and games exclusively using the keyboard, then an ordinary person is simply not able to do this. For all the time of existence, computer mice have undergone not so strong changes.
The first mice worked on the basis of a ball in the base. Moving it in different directions, the ball rotated and controlled the controllers.
Then he was replaced by optical mice based on LEDs. The first generation of optical mice required the obligatory presence of a special mat, on which shading was applied, which contributes to increased light reflectivity of the surface. Moreover, the first mice had personal mats, they could not be replaced with others.
The second generation of optical mice has a more complex device. A mini video camera is installed on the bottom of the mouse, which continuously takes microphotographs of the surface and compares them with each other to determine the displacement of the device.
Mice are newer devices. Among their advantages are low power consumption, reliability, lack of luminescence.
Another version of the mouse is found as an addition to the graphics tablet. Such induction mice are quite inconvenient to use, since they cannot be replaced with more comfortable ones that fit the hand, and the increased accuracy is discredited by the small ability to move away from the tablet with it.
Printers
These are printing devices. For all the time of its existence, printers have not changed much. Technologies are developing, laser printers are replacing inkjet printers, however, previous generations continue to live. What is the reason for this? The fact is that different types of printers are suitable for different types of printing. They all perform the same function and do not differ much in design. There are the following types of printers:
- matrix;
- jet;
- laser;
- thermal printers.
In the matter of choosing such a device, people usually adhere to personal preferences and habits. However, if you are going to print photos on it, and not just text documents, then laser is more suitable for you due to the increased print quality.
Scanners
An input device for a computer. The peculiarity lies in the fact that scanners enter information into the PC exclusively in graphical form. The development of scanners has stalled solely on changing their sizes. At first they became smaller and more compact, and then they were replaced by huge "combines" - output and input devices that combine a copier, printer and scanner.
Sound
Each of us likes to watch movies, listen to music at home. Speakers, headphones, audio systems and home theater systems, as well as headsets and microphones, all refer to audio output and input devices.
There are many different microphones and speakers, differing in the quality of audio recording or playback, respectively. Probably, anyone can determine for himself how good the sound of a speaker is. When choosing an audio system, it is also recommended to be guided by the design and power to your taste.
Video
To work with video graphics, special output and input devices are distinguished - cameras and projectors.
A projector is a device designed to create an image of an object on a large screen. There are the following types of projectors:
- Diascopic. The image appears due to the passage of light rays through a transparent film with a picture.
- Episcopal. Creates an image using the projection of reflected rays.
- epidiascopic creates an image of both transparent and opaque objects on the screen.
- Multimedia the projector is directly related to the topic of the article. This is a device for outputting graphic information from a computer to a large surface.
As for the cameras, there is no need to tell anyone. In most cases, the higher the resolution of the shooting camera, the better the finished picture. With the advent of laptops, USB cameras began to be replaced by built-in laptop monitors.
After reading this article, you learned what output and input devices exist, what types they are divided into, and what types of them are relevant today. If you are going to independently equip your work and play space, as well as independently choose the devices that you want to have at hand at home, then this article should help you with choosing gadgets.
Remember the main rule of the buyer: more expensive does not mean better. In a computer store, when purchasing a printer or headset, you may well overpay for the brand, and then regret your purchase for a long time.
HP printers are an example. Yes, they are considered one of the best, but replacing an empty cartridge or just a small malfunction will cost you a pretty penny solely because of the manufacturer's fame.
When buying a sound system, feel free to check the sound and performance of the speakers. And if you are going to buy a webcam, then test its image, since the resolution declared in the documentation may not always correspond to the existing one.
And the main rule. When purchasing any product, check with the seller for warranty information. For example, for some devices, services require the box in which the unit was shipped. A good example is Asus laptops. In most cases, nowhere on the store's website does it contain information that manufacturers require a branded box when contacting a service center.
Be careful and happy shopping!
1. Monitor (display) refers to the main devices of any PC, without which effective work is impossible. During operation, the display screen shows both the commands and data entered by the user, and the system's reaction to them.
Monitors can work in two modes: text and graphic. In test mode, monitors can only display a limited set of characters, and characters can only be displayed in certain positions on the screen (most often, 24 or 25 lines of 40 or 80 characters per line can be displayed on the screen); in graphics - they display both graphic and textual information, while the screen is divided into many dots (pixels), each of which can have one or another color. From these luminous points, an image is formed.
According to the number of reproducible colors, monitors are monochrome and color. Monochrome devices are capable of reproducing information in only one color, possibly with different shades (gradations of brightness). Color displays provide display of information in several shades of color (from 16 shades to more than 16 million). In fact, modern displays can display as many shades as the video card allows, whose memory stores information about the colors of the screen pixels.
According to the principles of image formation, displays based on a cathode ray tube, liquid crystal, plasma, and LED are distinguished.
Cathode ray tube (CRT) displays work like a television. Under the influence of electric fields in the "electron gun" the flow of electrons accelerates. Then, with the help of electromagnetic fields, the beam is deflected in the desired direction. Then this flux is focused, reaches the screen and makes a small speck of phosphor (screen grain) glow with a brightness proportional to the beam intensity. This is how monochrome devices work. In color monitors, the screen grain consists of three specks of a phosphor of different colors (red, green and blue) and electron flows are sent by three "guns", and the electron beam for each color must fall on its own phosphor. Advantages: modern CRT displays have high image quality, are quite cheap and reliable. Disadvantages: Such displays are quite bulky, consume a lot of energy, have a higher level of radiation than other types of displays.
Liquid crystal displays or LCD displays. Their action is based on the effect of liquid crystals losing their transparency when an electric current is passed through them. Advantages: liquid crystal displays do not create radiation harmful to the health of the user, are the most economical in energy consumption, and provide good image quality. Disadvantages: if you look at the screen from the side, you can hardly see anything.
Gas-plasma displays. The action is based on the glow of gas when an electric current is passed through it. The scheme is as follows: there are two sheets, between them there is an inert gas; one of the sheets is transparent, and the second contains electrodes to which voltage is applied. Typically, gas-plasma indicators consist of several similar elementary cells, the number of points in each of which is chosen in the most optimal way to display single characters.
LED matrices (LED displays). Usually used in embedded computers (used in automated lines in industrial production, in robotics, and so on) to display small amounts of textual information.
Diagonal screen size;
Screen grain size - the distance in millimeters between two adjacent phosphors of the same color;
Resolution - the number of pixels (screen dots) horizontally and vertically. It depends on the screen size and screen grain size, but can be changed (within certain limits) using software settings;
The number of transmitted colors (depends on the amount of memory of the video card);
The frame rate (sync frequency) is the number of images on the monitor screen redrawn by the electron tube beam per unit of time. Measured in hertz.
Compliance with safety standards: monitors with internal shielding and reduced radiation levels, the permissible level of radiation of the monitor, anti-glare coating, etc.
2. Video card is a device that controls the display and provides the output of images on the screen. It determines the resolution of the display and the number of colors displayed. The signals that the display receives are generated by the video card.
The ability of a PC to display information is determined by the combination (and compatibility) of the technical characteristics of the display and its video card, that is, the video system as a whole. Almost all modern video cards belong to combined devices and, in addition to their main function - the formation of video signals - they accelerate the execution of graphic operations. To do this, special processors are installed on the video card, allowing you to perform many operations with graphic data without using the central processor. Such devices are called video adapters. They significantly speed up the display of information on the display screen when working with graphical software shells, three-dimensional graphics and when playing dynamic images.
3. Printer- a printing device for obtaining a "hard" copy of a document. All printing devices are divided according to the principle of operation into matrix, inkjet, laser.
The principle of operation of dot matrix printers is that the head with needles, hitting the ink ribbon, leaves a symbol formed from a set of dots on paper. The advantages of this type of printers are high reliability and low cost of consumables. Disadvantages: strong noise, low quality and print speed, lack of automatic paper feed.
In inkjet printers, through special holes - nozzles - ink is blown out under pressure, thereby forming an image. Their productivity is noticeably higher than that of dot matrix printers. They work silently, have a fairly high print quality and automatic paper feed. The main advantage is affordable color printing. Disadvantages: the high cost of consumables, when moisture gets on the image, it leads to its spreading.
The work of laser printers is based on the principle of xerography - the image is transferred to paper from a special drum, to which particles of special ink (toner) are electrically attracted. When a sheet of paper is rolled along the drum, the design is transferred to the paper and then fixed by heat or pressure. Laser printers are very quiet and much faster than dot matrix and inkjet printers and produce high quality prints - very clear, high contrast. Disadvantages: requires very high quality paper, expensive color printing.
Main user characteristics:
Resolution;
The print speed is determined by two factors - the time of the mechanical paper feed and the speed of processing incoming data;
memory size; printers are usually equipped with a processor and internal memory (buffer) that receive and process data.
4. Plotter or plotter. The plotter is an output device that is used only in special areas. It is designed to display such graphic materials as drawings, graphs, diagrams, diagrams included in the set of design or technological documentation. The writing knot has several pins for fixing special felt-tip pens. The pins can be raised off the paper (no line is drawn) or lowered to draw. The node moves along the paper along special guides. Plotters are flatbed and rolled.
5. Video projectors- devices for displaying information on a light vertical surface (screen, wall).
6. Speakers, headphones– audio output devices.
I welcome you to the expanses of the blog about computers - the site. In today's third lesson, we will talk about additional devices that can be connected to the computer.
You can learn about the main devices of a computer in the lesson. Additional may be devices for input, output and input-output of information from a computer.
Output devices- These are devices that convert the digital type of data (located in a computer) into a form that is convenient for a person to perceive. For example, there is some document in the computer that you can print on the printer. In turn, the printer is an output device, that is, it displays in a tangible form what you see on the computer screen.
Input Devices are devices that are used to enter information into a computer. If the previous term meant that we take information from a computer, then the opposite is true here. For example, a computer mouse is an input device. We turn mechanical actions into a digital signal that is transmitted to a computer.
Let's consider what devices for input and output of information can be. Let's take the main ones that are used by both novice and hardened computer users.
Output devices
Let's start with the device that was mentioned above - the printer.
Printer is a device that translates text and graphics from a computer onto a piece of paper. This is the output of information from an electronic form to a physical one.
speakers and headphones- sound output devices, they convert the electrical signal that the computer produces into sound. I think everyone is familiar with them, I will not go too deep.
Projector- a device for displaying graphic and text information from a computer. Projects an image on a flat surface, magnifying it many times over.
The monitor (display) also belongs to the output devices, in fact, without it it is not possible to work at the computer (you could see it in the first lesson).
Input Devices
The most used input devices are the mouse and keyboard. The mouse can be called a continuous input device because it changes its position quite often and quickly. They are basic, but in today's article we are talking about additional devices, so let's move on.
Microphone A device that converts sound into an electrical current. The computer picks up these same current fluctuations and converts it into information (into an audio track) that you can record and listen to later on the same speakers.
Scanner A device that converts text and graphics from a physical object into an electronic one. Simply put, a scanner is the opposite of a printer.
Joystick- an input device that is often used in games. Replaces the mouse and keyboard.
I/O devices
These devices can both input information into a computer and output it. These devices include:
Flash drive(flash drive) - a device that stores information. This information can be manipulated. For example, copy files from a computer to a USB flash drive and vice versa.
Drive- allows you to write information from a computer to a medium (disk), and then copy it from the medium to a computer (for example, you recorded a hundred of your favorite songs and gave it to a friend, he copied them to his computer).
On this optimistic note, we end our tour of input and output devices. What have we learned in this lesson? We learned what additional computer devices are, what input and output devices are, and looked at examples of what they can be and their purpose. I wish you easy learning without suffering!
Today, the vast majority of desktop PC users are armed with a familiar mouse and keyboard. These input devices have long proven their viability and are the most versatile tools for most of today's common tasks. Nevertheless, in addition to these two "pillars", there are a huge number of alternative input devices of the most diverse design and purpose popular with certain user groups or existing only in the form of a few demonstration prototypes. This review is devoted to consideration of such devices.
Non-traditional keyboards
It seems that the principle "the best the enemy of the good" has long been discarded as unnecessary by the developers of computer keyboards. It would seem that there is nothing to improve: by trial and error, the optimal key sizes, their layout, etc. were found. But keyboard makers are constantly coming up with new ideas and trying some very unusual and daring technical solutions. And in this case, we are not talking about such cosmetic measures as placing a group of additional shortcut buttons (now this is already perceived rather as the norm), but about much more serious design changes.
About four years ago, the first serial models of flexible keyboards appeared. One of the pioneers in this direction was Flexis, which released the FX100 keyboard for use with keyboardless PDAs. Silicone is used as the main material for the manufacture of such a keyboard, since its properties allow the product to fully restore its original shape even after prolonged storage in a deformed (folded) form. In addition, the silicone keyboard is water and dust resistant, which greatly increases its reliability and durability, especially when working in the field. If the surface of the keyboard is heavily soiled, you can rinse it under running tap water (of course, do not forget to close the interface connector first). Another positive point is the extremely small thickness and weight - only 68 g with dimensions of 85X250X4 mm. Unlike many models of hard keyboards produced for use with PDAs, Flexis does not require the installation of batteries for operation, receiving the current necessary for operation from the device itself.
Currently, Flexis produces a whole series of flexible keyboards designed for both PDAs (with a universal interface that allows you to connect to models from different manufacturers) and desktop computers and laptops (with USB interface). Flexible keyboards are also produced by Plycon and several other manufacturers.
Another interesting direction is the "crossing" of keyboards of various types. Late last year, Creative released the Prodikeys keyboard, which features a conventional 104-key computer keyboard at the top and a three-octave music keyboard with velocity-sensitive keys at the bottom. The music section of the keyboard (37 keys) can be closed with the included cover, which, when used with a conventional keyboard, also functions as a wrist rest. In addition to the music keys, on the left side there are two MIDI controller wheels (controlling transposition and volume) and a music software shortcut button.
While some manufacturers are increasing the number of buttons on keyboards, others are trying to reduce their number as much as possible. The main goal of such innovations is to reduce the dimensions of the keyboard, while maintaining the convenience of its use. Experiments in this area are actively engaged in the developers of a small American company FrogPad. On the mini-keyboard of the same name created by them (127X89X10 mm) there are only 15 main full-size keys and 5 modifier keys. The design of FrogPad is optimized for typing with one hand and, despite the small number of buttons, allows you to not only enter all letters, numbers, punctuation, standard characters, but also use the function and navigation keys. In this case, the user does not need to press more than two keys at the same time.
According to the developers, due to the intuitive key layout principle, you can master typing on FrogPad in 6-10 hours.
And thanks to its small size, this keyboard can be used when working with desktop PCs, laptops, pocket and tablet computers (FrogPad modifications are available with USB and Bluetooth interfaces). Versions of FrogPad are currently shipping, adapted for typing in English and Japanese. Whether there will be localized versions of FrogPad for other languages is still unknown: unlike conventional keyboards, which can be “localized” with transparent stickers, FrogPad will require major software development.
The projected keyboard in action. Perhaps in the future, such solutions will become widespread in the CPC.
Minimization peaks were reached by the creators of the so-called virtual keyboard from iBiz Technology, who decided to do without buttons at all. The image of the keyboard is projected by a laser onto any flat surface, and special sensors track the "pressing" of the user's fingers on the virtual buttons. This lighter-sized device weighs approximately 60 g. It uses a lithium-ion battery as an autonomous power source, providing 3 to 4 hours of operation without recharging.
Modifications of the virtual keyboard have been developed for various models of PDAs, as well as desktop PCs and laptops. The device is ready for mass production, and the iBiz website has already begun accepting pre-orders. Deliveries of iBiz Technology virtual keyboards were supposed to begin this spring, but the company faced some difficulties in finding a partner willing to provide its production facilities for the mass production of these devices.
trackballs
At present, trackballs have almost been forgotten, but it is impossible not to mention them: firstly, some models of these devices are still produced to this day, and secondly, for a number of tasks that require special accuracy (for example, architectural and design programs), trackballs are suitable much better than mice.
If we ignore the details, then the trackball is a classic mouse 1 turned upside down with its “belly”. Accordingly, it is controlled not by moving the manipulator itself (as in the case of a traditional mouse), but by rotating the ball in the desired direction with the fingers or the back of the hand.
In diameter, the trackball ball is much larger than the similar element of the mouse, but, as a rule, it is lighter. As a result, trackballs provide more precise control than mice. In addition, the trackball requires much less space than a mouse because it does not need to be moved around the table during operation. By the way, due to this, the load on the muscles of the hand is reduced and the risk of occupational diseases associated with this is significantly reduced. Another advantage of the trackball is the possibility of full control even if the manipulator is not on the table, but directly in the user's hands (this can be useful, in particular, to control an electronic presentation).
Unlike mice, different models of trackballs can vary significantly in design. In traditional trackball designs, the ball is located in the center of the manipulator, and in this position it can be scrolled with the index, middle and ring fingers or the back of the hand. However, today you can find the most unexpected and sometimes very controversial designs: the ball can be shifted to the side or located on the side (under the thumb or under the ring and index fingers).
As in mice, almost all modern models of trackballs use optical sensors this avoids the problems associated with the loss of performance of the manipulator when the ball is dirty. And in addition to the two main buttons inherited from mice, modern trackball models are often equipped with additional controls scroll wheel and additional keys.
1 In this context, we are talking about mechanical and optical-mechanical models of mice, the main structural element of which was a rubberized ball that drives the axis of the displacement sensors.
Graphic tablets
To work with many graphic applications, the mouse is often too rough and uncomfortable tool, significantly limiting the potential of these products. More specifically, a traditional mouse design does not provide the necessary positioning accuracy and (more importantly) is not able to perceive changes in pressure (pressure), which, in turn, makes it impossible to use the traditional pencil and brush drawing technique. To verify this, you can conduct a simple experiment: try to draw your autograph with the mouse in the window of any graphics editor in most cases, the result is very far from what you want.
For full-fledged work with graphic applications, special devices were created - graphic tablets, or, as they are sometimes called, digitizers. Tablets work with special tools pens (styluses) and mouse-like manipulators. The first models of such devices were very expensive and were intended mainly for professional use in computer graphics and computer-aided design systems.
The qualitative leap in the development of digitizers was largely due to the efforts of Wacom developers. It was they who first created a tablet that is sensitive to the pressure of the stylus, as well as a tablet with a wireless pen.
Wacom Volito Affordable graphics tablet with wireless, battery-free pen and mouse
Thanks to the advent of such devices, artists were able to use the traditional technique of working with charcoal, pencil and paint to create works on a computer. Then there were models with a wireless batteryless pen, powered directly from the active area of the tablet.
In the late 90s, budget models of graphics tablets began to appear on the market, aimed at the non-professional market (mainly home PC users), and today almost any owner of a home computer can purchase an inexpensive graphics tablet. In addition, recently the number of small-sized tablet models oriented to office use has been increasing (such models are often equipped with programs for handwriting recognition).
Recently, there are more and more graphics tablets focused on working with office applications.
Currently, Wacom products account for about 80% of the graphics tablet market. In addition, devices manufactured by KYE Systems (Genius) and Aiptek are also represented on the Russian market.
Wacom Cintiq 18sx 18" LCD and professional pen tablet hybrid
In 1998, Wacom introduced a revolutionary new product, the LCD combined with a graphics tablet. Compared to traditional graphics tablets, this device is more convenient because it allows you to draw directly on the screen, almost the same as on paper or canvas. True, due to the high price, such devices are not widely used.
Wacom currently produces two tablet display models called the Cintiq based on 15-inch (1024X768) and 18.1-inch (1280X1024) LCD displays. These devices can be connected to both analog (VGA) and digital (DVI-D) outputs of the video adapter, and a serial port and USB are provided for entering information into a computer.
It is worth mentioning that attempts were made to create a stylus that could be used without a tablet at all. For example, Logitech's line of input devices includes the io Personal Digital Pen. This device looks like an ordinary fountain pen and allows you to write with ink on plain paper, and a sensor hidden inside the body tracks the trajectory of the pen on paper and stores it in the built-in memory that can hold up to 40 handwritten pages.
Recharging the io Personal Digital Pen and copying the drawings recorded in the device's memory to a PC is carried out using a special cradle connected to the USB port. The software installed on the computer allows you to recognize handwritten text and edit it electronically.
Hand scanners
Oddly enough, hand-held scanners remain in the arsenal of PC users to this day, although, of course, modern representatives of this type of device have little in common with hand-held scanners produced in the early 90s.
C-Pen hand-held scanners are designed for line-by-line input of text and numeric data from various opaque originals: books, printouts, magazines, newspapers, etc. This is a very handy tool for those who work with large volumes of printed materials, selecting individual quotes, numbers, addresses, and so on. In order to enter a single line, word or symbol, you do not need to scan the entire page just move the scanner tip over the desired section of text, as is done when highlighting text fragments with a marker.
C-Pen 10 handheld scanner allows you to enter text information from various originals
The C-Pen 10 scanner is connected to a computer via a USB interface, from the port of which it also receives the power supply necessary for operation. In terms of dimensions (122X19X23 mm), this model is quite comparable to a conventional marker. The size of the input area is 7.2x5.5 mm, and the scanning resolution is about 400 ppi. The characteristics of the C-Pen 10 allow it to be used for entering typed text in sizes from 5 to 22 points, with a maximum speed of 15 cm/s. The scanner comes with special software for Windows OS, which allows automatic recognition of numbers and texts in 23 languages.
In combination with the included special mat C-Pen 10 can also be used as a manipulator (instead of a mouse or touchpad). The mat has 10 areas that act as customizable shortcut keys.
The C-Pen 600mx is actually a specialized mini-computer for processing text data and allows you to perform text recognition offline. In addition to the scanning unit, the C-Pen 600mx is equipped with a monochrome LCD graphic display, a universal control (rocker) and an infrared interface. Thus, C-Pen 600mx allows you to scan and automatically recognize text (unlike C-Pen 10, this operation is performed inside the device itself), store recognized text fragments in internal memory, exchange various text data with desktop, portable and pocket PCs, as well as recognize letters and numbers "written" by the user using the C-Pen. In addition, the C-Pen 600mx can also be used as a pocket translator: for this, you only need to download the dictionary databases of the desired language from the manufacturer's Web site.
Interactive touch screens
Interactive touch screens greatly expand the functionality of large screen display panels used in educational institutions, press centers, exhibitions, etc. The touch screen with a transparent pressure-sensitive surface is mounted directly on the body of the liquid crystal or plasma display panel. A wide range of interactive touch screens under the SmartBoard brand for display panels from various manufacturers is produced by SMART Technologies.
Touch screens can significantly expand the functionality of display panels with large screen sizes
By installing the SmartBoard touch screen on the display panel and connecting it to a computer, you can control the movement of the cursor with your finger (pointing to the desired point on the screen). In order to focus the attention of the audience on a certain part of the image or text, there are special markers located on a special stand (Pen Tray). You can use the markers on the screen to draw lines, fill areas, and write handwritten text. The applied elements appear directly on the screen image, which allows, if necessary, to save or print the current picture with the marks made. To remove unnecessary lines or inscriptions, the user has a special tool "eraser".
An important component of the touch screen is specialized software. In the program settings, you can set the color and line thickness for each of the markers used, as well as activate the text underline mode (in this case, the letters are displayed over the line drawn by the marker). In addition, the software package includes applications that implement virtual keyboard and handwriting recognition modes.
One of the undoubted advantages of interactive touch screens is their ease of mastering - usually only a few minutes are enough for training, so even people who are completely ignorant of a computer can work with them.
Game controllers
If we evaluate the degree of popularity of various types of alternative input devices, then, apparently, the main contenders for the top position will be game pads. With the development of such game genres as simulators of various vehicles, it became clear that the use of a traditional keyboard and mouse, in principle, does not provide the proper convenience and flexibility in controlling the gameplay. As a result, whole classes of specialized game manipulators have appeared, the design of which is optimized in accordance with the features of games of one kind or another. Perhaps one of the most important events that had a huge impact on the development of devices in this class was the advent of haptic feedback technology in 1995 (for more details, see the sidebar).
Haptic FeedbackConsidering the modern industry of game manipulators, it is impossible not to touch on the topic of tactile feedback (force feedback). The main goal pursued by the developers of tactile feedback mechanisms for game manipulators was to make the gameplay more realistic and exciting. To the two main channels through which the user perceives the virtual space, that is, to hearing and vision, a third tactile is added. To fully implement the functions of haptic feedback, two main components are needed: firstly, special mechanical drives inside the manipulators, and secondly, a unified set of commands (API), through which game applications will control the active mechanisms of the manipulators. In 1995, the developers of Immersion Corporation created both of these components TouchSense technology (on the basis of which the active manipulator hardware is implemented) and an API called I-Force. Subsequently, I-Force became the most common tactile feedback API for PC-based computer game controllers equipped with movable controls (joysticks, steering wheels, helms, etc.). To a large extent, this was facilitated by the close cooperation between Immersion and Microsoft: an improved version of this API (I-Force 2.0) was included in DirectX 5 and was retained in subsequent versions of DirectX.
TrustMaster Top Gun AfterBurner Force Feedback "aviation" joystick with full support for haptic feedback effects With the help of I-Force commands, you can implement control of three different types of tactile effects:
It is worth noting that the TouchSense technology allows you to implement tactile feedback effects in a wide variety of manipulators both in gaming and in conventional ones (for example, in mice). Depending on the capabilities supported by the manipulator, all devices equipped with a tactile feedback mechanism can be divided into three classes:
Logitech WingMan RumblePad vibration-enabled gamepad The first joystick with a tactile feedback mechanism was released in 1996 by CH. Over the next two years, virtually every leading gamepad manufacturer licensed TouchSense technology and began producing gamepads with tactile feedback. As such devices spread, so did the number of games with force feedback support. Today on the shelves of computer stores you can find a huge number of a wide variety of game controllers equipped with a tactile feedback mechanism. The tools available to developers make it possible to use tactile effects not only in games, but also when working with a wide range of applications: office programs, flash, Internet browsers, etc. |
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The use of tactile feedback mechanisms has caused significant changes in the internal structure of game manipulators. Firstly, electric motors appeared in them, through special drives acting on the controls and the body of the manipulator to create "power" effects. Secondly, to control the operation of electric drives (which requires real-time processing of a large flow of information coming from both the computer and the sensors of the controls), they began to use a specialized processor built directly into the body of the manipulator. Thus, game controllers, which were originally rather primitive structures built on the basis of several passive elements, in a very short time turned into very complex electronic devices equipped with their own microprocessors.
Joysticks
Joysticks of classical design, that is, made in the form of a vertical lever, became the first mass type of computer game manipulators. Such joysticks are most popular among fans of flight simulators and other games related to the control of various aircraft.
Logitech WingMan Force 3D classic design joystick with haptic feedback mechanism
Since its inception, joysticks have gone through several stages of evolution, and today on sale you can find both very simple and very intricate designs, equipped with tactile feedback mechanisms and equipped with handles of the most bizarre shapes. Some manufacturers are experimenting with "crossing" manipulators of different classes: for example, Saitek SP550 Pad & Stick Fusion is an original combination of a classic joystick and gamepad.
Currently, quite a few models of specialized aviation joysticks are being produced, made in the form of controls for real-life aircraft models (in particular, the TrustMaster HOTAS Cougar copies the controls of the American F-16 military aircraft). Such manipulators are equipped with an additional engine control handle (Throttle), which in some cases is made in a separate housing and, if necessary, can be detached from the main module.
TrustMaster HOTAS Cougar replica F-16 aircraft controls
Recently, fans of flight simulators have become increasingly popular with joystick models equipped with a tactile feedback mechanism. The most striking example is the TrustMaster Top Gun AfterBurner Force Feedback, which has a removable unit with an engine control handle. The tactile feedback mechanism of this device is implemented using Immersion TouchSense technology: two powerful electric motors located inside the joystick simulate the vibrations of the aircraft body, the aerodynamic load on the controls, impacts during collisions, shocks during rocket launches and other effects.
Gamepads
Gamepads, or gamepads as they are more commonly known, came to the world of computer accessories from the related field of television game consoles. A typical gamepad is a compact unit with buttons placed on it. Due to the smaller number of buttons (compared to a standard computer keyboard) and the special shape of the case, the gamepad is convenient to use while holding it in your hands.
TrustMaster Firestorm Digital 2 traditional design gamepad
As gamepads developed, their design gradually became more complicated. Along with the usual buttons for this class of manipulators, other controls began to appear over time. So, in modern models of gamepads, a mini-joystick is widespread a small four-position swinging pointer that can be controlled with one finger. On sale you can find models of gamepads equipped with both one and two mini-joysticks.
On some models of gamepads, flat multi-position pointers are installed. Functionally, they are similar to mini-joysticks, but they are made in the form of a flat rocker key, which allows, depending on the design, to receive pressing in four or eight directions.
A number of models of modern gamepads (for example, the Logitech WingMan RumblePad) even have sliders that allow you to smoothly change the values of the parameters associated with them.
Manufacturers are also experimenting with non-traditional control methods. So, in a number of gamepad models (as a rule, the word tilt is present in their name), special sensors (accelerometers) are used to register the tilt of the manipulator body in four directions (forward, backward, left and right). Examples of such devices include the Gravis Destroyer Tilt and the Saitek P2000 Tilt Pad. True, such solutions have not yet received wide distribution.
There are also models of gamepads with a tactile feedback mechanism, but most of them support only a limited set of tactile effects, namely vibration effects (rumble feedback).
Belkin Nostromo SpeedPad n52 gamepad that complements the mouse and is designed for the left hand
In addition to the many gamepads made in the already familiar “two-horned” case, very original designs are also being produced. For example, this year Belkin introduced a device called the Nostromo SpeedPad n52, designed to be used with a computer mouse. The design of this gamepad, installed on the surface of the table, is designed for the left hand. Nostromo SpeedPad n52 is equipped with ten “keyboard” buttons, a flat eight-position pointer placed under the thumb, and a rotating wheel.
TrustMaster Tacticalboard gamepad for fans of strategy games
Until recently, manufacturers of game controllers did not honor fans of strategic games with their attention. But this gap was filled by TrustMaster, which created a specialized strategic gamepad called Tacticalboard. It is equipped with 42 keys, for the convenience of users, painted in different colors and distributed over several functional groups.
Steering wheels and pedals
A significant part of the computer games released today are racing simulators remember at least last year's triumph of Need for Speed: Underground or the agonizing wait for the new version of Colin McRae Rally. Therefore, it is not surprising that every year the number of game manipulators, made in the form of ground vehicle control tools - steering wheels and pedals, is increasing. Currently, rudders with a tactile feedback mechanism are in the greatest demand.
In addition to the steering wheel itself, most models of manipulators of this class are provided with paddle levers (one or two pairs). Most often, these controls are ordinary switches (usually used to control the gearbox), however, in some models of manipulators (for example, in the TrustMaster F1 Force Feedback Racing Wheel), the paddles allow you to smoothly change the values of the parameters associated with them in this case, they can be used instead of the accelerator and brake pedals.
Steering wheel with paddle shifters and gearshift lever (right) operating in sequential mode
A less common control is the shift lever, which can be mounted directly on the steering wheel assembly or made as a separate module. In most models of manipulators, the lever deviates in two directions, allowing only sequential (sequential) gear shifting. However, in a number of expensive models of automobile manipulators, the possibility of arbitrary gear shifting according to the H-shaped scheme more familiar to road cars is provided. For example, in addition to the basic kit of the Act Labs Force RS manipulator, you can purchase a separate RS Shifter unit, which allows you to shift gears both in random order (in an H-pattern) and in sequential mode.
Available from Act Labs, the RS Shifter add-on unit allows you to control the shifting of gears in the usual H-pattern for road cars
As for the pedals, the vast majority of car manipulators are equipped with a floor platform with two pedals (accelerator and brake by default). For connoisseurs of absolute realism, kits are available that are equipped with three pedals, and the third pedal is made removable so that the manipulator can be used in games that do not support the clutch control function. However, for such delights you have to lay out a very impressive amount, and besides, one cannot ignore the fact that only a very limited number of car simulators have the ability to fully control the clutch.
Along with the dominant positions of automobile manipulators, the so-called motorcycle direction has recently been developing in this class. The number of models of such steering wheels is still significantly inferior to car manipulators, but they can be found in some domestic computer stores. An example of a motorcycle steering wheel is the Thrustmaster FreeStyler Bike manipulator, which allows you to perceive not only the turn of the steering wheel, but also the tilt of the upper body relative to the base. The FreeStyler Bike handlebar has one revolving knob and two levers. There are also much more familiar controls 11 buttons and a flat four-position pointer.
On the way to a 3D interface
according to unofficial information, elements of a three-dimensional interface will be used in the next version of Windows. Similar rumors come from developers of operating systems for mobile devices. Naturally, for the comfortable use of such innovations, a serious modernization of input devices will be required, and work in this direction is already underway.
It is likely that one of the main technologies of the future will be gesture recognition. The most affordable devices today that allow you to implement gesture recognition on a PC are Web cameras. In a number of modern gaming applications, the possibility of changing the viewing area depending on the position of the user's head, as well as entering some commands using gestures, has already been implemented. However, it is likely that other, more reliable and easy-to-use "gesture catchers" will appear soon.
So, in one of the laboratories of the Massachusetts Institute of Technology, work is underway to create a manipulator capable of registering movements in three dimensions. In addition to registering the current coordinates in three-dimensional space, using such a manipulator, it will be possible to recognize gestures and, using specialized software, convert them into certain commands.
And the research division of Toshiba has developed an unusual remote control for household appliances. This pager-sized remote is worn on the wrist and, thanks to the presence of accelerometers (acceleration sensors), allows you to control equipment using gestures (a total of nine types of gestures are recognized). For example, by pointing at a device with your hand, you can turn it on or off, and by moving your hand up or down, you can adjust certain parameters (for example, the desired air temperature when controlling the air conditioner).
Or Graphics tablet, - a device for digitizing graphic images, which allows you to convert an image obtained as a result of the movement of the operator's hand into a vector format.
Digitizers are used in computer-aided design (CAD) systems to enter graphic information into a computer in the form of drawings and drawings: the designer moves the pen-cursor over the tablet, and the image is recorded as a graphic file.
The digitizer consists of two elements: base (tablet) and pointing device (pen or cursor) moved on the surface of the base. When you press the cursor button, its position on the surface of the tablet is fixed and the coordinates are transferred to the computer.
Digitizers are divided into electrostatic and electromagnetic, depending on the mechanism for determining the location of the pointing device.
Graphic tablets of digitizers are made on firmaments (tablet digitizers) and flexible bases (flexible digitizers). Flex-based digitizers are lighter, more compact, easier to transport, and cheaper.
Pointing devices in digitizers, they are performed in the form of a cursor or a pen.
The pen is a pointer equipped with one, two or three buttons. There are pens that determine the force with which the pen tip is pressed against the tablet, and have 256 degrees of pressure. The thickness of the line, the color in the palette and its shade depend on the degree of pressure. To realize artistic possibilities, you need software such as Adobe Photoshop , CorelDRAW and etc.
Cursors are mainly used by CAD designers. They are performed by 4-, 8-12-, 16-keys. Usually two to four keys are used, the rest are programmed in application programs, for example, in Autocad. One of the best is the 4-button cursor from CalComp.
Lesson topic. Information output devices.
About 10 years ago it was only a dream to work on your computer like a typewriter or organize a mini-printing house with it, watch TV programs, listen to CDs.
But time flies quickly, and today everyone knows those peripheral hardware that help bring the possibilities of personal computers closer to almost limitless.
Of course, we are talking about all kinds of information output devices, the main purpose of which is to convert the information contained in binary digital form in the machine's memory into a form understandable for human perception.
Output devices are computer hardware designed to output digital information from it by converting it into an analog form and presenting it in a form understandable to a person.
The hardware of any output device, as well as the input device, includes the device itself, the control unit - the controller (or adapter), interface cords with connectors corresponding to the ports on the motherboard, and the driver of this particular device.
We know that thanks to their senses, a person can perceive visual, symbolic, audio information, tactile (tactile) information, smells and tastes.
From these forms today's personal computer, perhaps, cannot satisfy only our sense of smell and taste buds - the output of "smelling" and "tasty" information is the prospect of the future. But the computer gives out all the other forms understandable to us in a completely real form.
According to this, we can divide all information output devices into several classes:
Monitors - output of video information;
Printers - output of sign-written information;
- plotters(plotters) - output of graphic information;
Speakers, headphones, speakers - output of sound information;
Virtual reality devices - output of tactile information.
Lesson topic. Monitors: classification, characteristics and principle of operation.
1. Monitors: classification, characteristics and principle of operation.
Monitor— this is a device for displaying symbolic and graphic information on the screen, by converting its computer (machine) representation into a form understandable to humans.
It can be said that a monitor is a device for displaying visual (visual) information.
Otherwise, monitors are called displays, less often - video terminals (usually this is the name of a monitor remote from other parts of the computer). The monitor is one of the main parts of a PC, and the convenience of using a computer largely depends on its characteristics.
The monitor is connected to the motherboard through a video adapter board (video card), and its normal operation is ensured by a set of drivers - a special program that comes with the monitor.
The combination of a monitor, video card and their drivers forms the video system of a personal computer.
Today you can meet a huge number of monitors of various brands and models. In order to somehow understand their diversity, you need to clearly understand the signs by which they are classified.
We will consider their classification according to:
1) the size, which is determined, as with TVs, along the diagonal of the screen;
2) functional features - alphanumeric or graphic;
3) the number of reproducible colors - monochrome or color;
4) the physical principles of image formation - based on a cathode ray tube (CRT), liquid crystal, plasma and electroluminescent.
A reasonable choice in terms of "screen size" among monitors can be a display with a diagonal of 17 inches or more.
Alphanumeric monitor(today, by the way, you will not find it anywhere) can only reproduce a limited set of characters. It can be compared to the display of conventional electronic wristwatches, where only numbers and letters can be seen. You can’t reproduce complex pictures on it.
Graphic monitors adapted to reproduce any information: both digital and graphic.
Monochrome monitor can reproduce the image in any one color with different gradations of brightness. A color monitor displays an image in several colors at once. Their number can be from 16 to 16,800,000.
Plasma displays are a set of gas-discharge cells - they are expensive, and their energy consumption is quite high.
Fluorescent displays consist of a matrix of active indicators that give a high-quality image, but they are also very energy-intensive and expensive.
Base monitors cathode ray tube (CRT) They work according to the same “principle as ordinary TVs: the electron beam emitted by the electron gun is modeled by special electrodes and hits a screen covered with a phosphor. An image on a screen is made up of many individual dots called pixels.
Pixel— the minimum size of the image on the screen.
Under the action of the sweep, the electron beam slides across the screen line by line and forms an image.
Colors on the monitor(as on a television screen) are obtained by an additive (total) mixture of three primary colors: RGB, i.e. red (Red), green (Green) and blue (Blu). This triad, mixed with the same intensity, gives a white color, and in order to achieve color shades, the intensity of each of these colors is dosed in the required proportion.
The electromagnetic radiation of CRT monitors is generated by a gun that accelerates electrons and is located at the back of the monitor, and X-ray radiation occurs at the moment of collision of electrons with the inner surface of the screen. Of course, modern CRT monitors have anti-radiation protection, but it is not possible to completely suppress the resulting radiation.
LCD monitor does not have these shortcomings: its electromagnetic fields are at the level of the background from the power supply, and the image it creates does not flicker at all. This circumstance alone makes those who are professionally connected with computer technology seriously think about purchasing an LCD panel. The disadvantages of the LCD monitor include not-yet-sufficiently accurate color reproduction, as well as uneven image brightness. In favor of purchasing an LCD monitor is its ergonomics. This applies to those who spend a lot of time in front of the TV screen. The fact is that some models of LCD monitors, in addition to the standard VGA input for connecting to a computer, also have a video input, to which you can send a signal from a TV, TV tuner or VCR. This makes it possible to get rid of the harmful effects of a television CRT, which is much stronger than that of a CRT monitor.
Modern thin-film semiconductor liquid crystal monitors use TFT technology. The liquid crystal substance is located between two layers of glass.
The high efficiency of LCD monitors is due to the low consumption of materials and energy.
Traditional CRT monitors update the image on the screen by one pixel, so the frame rate is extremely important for them, which determines the refresh time of the image. The visual flickering of the image on the screen depends on its value. In LCD monitors, the image is updated progressively, so it does not judder at almost any reasonable frame rate.
With the same size and high image contrast, LCD panels have an undeniable advantage over traditional CRT monitors: they are much lighter and take up very little space, and some models can be hung on the wall, which completely saves you from having to allocate space under the monitor in the workplace. table.
Attention should be paid Another convenient feature that some models of LCD monitors have is the ability to rotate the display by 90 ° and thus change the landscape orientation of the screen to portrait. This is very useful when working with Web pages or large documents, where the extra height of an image in portrait orientation is very useful.
The main features of monitors are permissiveability, the sizescreen coverage points and frame rate.
Resolution is the maximum number of dots (pixels) that this type of monitor can display horizontally and vertically.
It is clear that the more these points fit horizontally and vertically, the better the picture on the monitor will be.
The resolution depends both on the characteristics of the monitor itself and, even to a greater extent, on the characteristics of the video controller, which provides for two monitor operation modes: text and graphic.
The clarity of the image on the monitor screen depends on the resolution value, and it is generally accepted that in text mode monitors do not differ much from each other in image clarity, and in graphics mode, image quality increases with increasing resolution.
The image quality is significantly affected by such a physical parameter of the display as screen dot size, or, as computer scientists say, "phosphor grains." This parameter defines the distance between points.
For modern monitors currently on sale, this parameter varies from 0.32 mm to 0.25 mm. Do not confuse the concepts of "grain" and "pixel". The grain size cannot be changed, and the pixel size depends on the video adapter mode. A good monitor should be considered a display with a dot size of no more than 0.28 mm.
For another important feature monitors applies max. to adhr sweep frequency. Good stability of the image and the absence of flicker on the screen depend on it. The higher the frame rate, the less "ripple" your monitor screen will have.
It is recommended to use monitors with a refresh rate of at least 85 Hz, which means that the image on the screen is updated 85 times per second. A lower frequency is dangerous for the eyes - flickering is tiring and can lead to premature loss of vision.
note that all the most important characteristics of the monitor are directly related. Changing one of the parameters will lead to a change in the operation of the other, for example, by reducing the resolution, the number of supported colors will increase (as, indeed, the maximum scanning frequency).
Almost all modern monitors are equipped with a special digital control that allows you to manually adjust a variety of parameters:
· proportional compression/stretching of the image horizontally and vertically;
image shift horizontally or vertically;
Correction of "barrel-shaped distortions" (that is, those when the edges of the image on the screen are too convex or, conversely, concave);
trapezoidal and parallelogram distortions, also associated with the "geometry" of the image;
color "temperature", i.e. the ratio of the main screen colors - red, green and blue.
On professional monitors high-class, you can find dozens of other various settings and adjustments, many of which are carried out directly from the computer.
The back side of such monitors is decorated with many unusual connectors through which fine-tuning of colors and image parameters is carried out. In particular, the so-called "calibration" - the exact adjustment of colors on the monitor to the specified standards.
Lesson topic. Video adapters.
Video card (video adapter). The main purpose of a video card is to control the process of displaying information on the monitor screen, its characteristics must correspond to the monitor parameters. The higher the resolution of the monitor screen and its size, the higher the requirements for the video card. Structurally, a video card is usually made in the form of an expansion board, which is inserted into the corresponding slot on the motherboard. In older computers, ISA buses were used for this, then PCI. In modern computers, the video card uses a special slot - AGP.
The main components of a modern video adapter are a video controller, video BIOS, video memory, a special RAMDAC digital-to-analog converter, and interface chips with a system bus.
All modern video subsystems can work in two main video modes: text or graphics. Text mode in modern operating systems is used only at the boot stage.
In graphics mode 1 ... 32 bits are allocated for each image point (pixel) (from monochrome to color). The maximum resolution and the number of reproducible colors of a particular video subsystem primarily depend on the total amount of video memory and the number of bits per image element. There are several video card standards. The main parameters in these standards are resolution (the number of pixels horizontally and vertically), the number of colors displayed on the screen and the frame rate, which determines the frequency of redrawing (regeneration) of the image on the monitor screen.
Currently, all video cards must comply with the VESA SVGA standards, which defines the following main characteristics:
resolution - the number of horizontal pixels x the number of vertical pixels:
640x480; 800x600; 1024x768; 1152x864; 1280x1024; 1600x1280; 1800x1350;
color depth - the number of bits per pixel (colors).
Frame rates(56; 60; 72; 75; 85; 90; 120 Hz). Frame rate is an extremely important parameter in terms of ergonomics. The image on the monitor screen is drawn by an electron beam with a frame rate equal to the frame rate. If this frequency is below 75 Hz, then the eye has time to notice the flickering of the image, which is tiring for it. The flicker is most noticeable on a white background.
In order to set the desired color depth, open the Control Panel and select "Display" (or right-click on the desktop and select "Properties"). Go to the "Settings" tab. In the "Color Palette" section, select the desired mode and click the "Apply" button.
Set to HighColor or TrueColor for normal operation.
Video memory size. This parameter determines the ability of the card to support various options for displaying images on the monitor screen.
Video memory size required to support a particular mode is determined as follows: you need to multiply the number of image pixels horizontally and vertically by the number of bits and divide the resulting value by 8 (the number of bits in a byte). This way you can get the maximum possible resolution for different amounts of video memory. It is easy to determine that to support the maximum resolution of 1600x1280 at a color depth of 32 bits, 8 MB of video memory is required. Working with graphic applications, three-dimensional graphics and video imposes increased requirements on all the characteristics of a video card, especially on its memory. Therefore, cards with a memory capacity of at least 128 MB are currently being produced.
Security standards. There are several standards that leading monitor manufacturers adhere to. We list only the most famous.
Standard DPMS defines the power management modes that can be used when the monitor is idle.
In mode Standby only blanking of the screen occurs (switching off the high voltage on the kinescope), in the mode Suspend- decrease in the temperature of the filament of the CRT cathodes.
Modern motherboards support another mode - Hibernate("hibernation"). When you enter this mode, the entire contents of RAM are saved to the hard disk, the monitor and hard drives are turned off, after which the computer turns off. The advantage of this mode is that when the computer is activated, which is usually carried out by pressing any key on the keyboard, the state of the desktop, open and minimized windows is restored, i.e. the computer completely reproduces its state at the time of "falling asleep".
Swedish Nutek Specification- The National Council for Industrial and Technical Development of Sweden, requires that the monitor switch to the first energy conservation mode (Standby) occurs if the mouse or keyboard has not been used for more than 5 minutes (but less than 1 hour); at the same time, the monitor can return to its normal state in 3 s. In this mode, the power value must necessarily be less than 30 W, and preferably less than 15 W. After 70 minutes, the power consumed by the monitor must be reduced to a level of less than 8 W, and preferably to a level of less than 5 W. The exit time from the second mode (Off) is not defined. Nutek's energy efficiency levels have been included in the TCO"92 and TCO"95 rating systems.
The abbreviation TSO stands for as the Swedish Federation of Trade Unions. Initially, environmental standards applied only to monitors as the most dangerous element of a computer. The developers were only interested in minimizing the level of various radiations. TCO"92 turned out to be very tough in this sense. Its successor TCO"95 only expanded the scope of TCO, for the first time making an attempt to describe the requirements for other computer elements. In addition, special attention has been paid to the protection of the environment during the production process and to the safe disposal of all certified products after their useful life. The requirements of the TCO "99 standard are mainly focused on ergonomics, ecology and environmental protection. From now on, LCD monitors, computers, laptops and keyboards fall under the standard as a separate line.
All requirements of the TCO "99 standard are combined into seven groups:
1. visual ergonomic requirements (image clarity requirements);
2. visual ergonomic requirements (image stability requirements);
3. factors of external influence;
4. requirements for emissions and energy saving;
5. electrical safety requirements;
6. environmental requirements;
7. additional features.
Lesson topic. Additional video signal processing devices.
To better understand what will be discussed, imagine a stereo movie. Remember, in the recent past, we had stereo cinemas in our country, where before watching a movie, each viewer was given stereo glasses. And if a tree fell on the screen, then, looking at it through the stereo glass, the whole hall deviated, since there was an illusion that the tree fell exactly on you. It was the effect of "virtual reality".
Virtual reality is the process of modeling physical effects using video technology.
Image- this is what the user of a personal computer is dealing with. This means that in order to achieve the “stereo” effect on the monitor screen, it is necessary to make a “three-dimensional” image from a two-dimensional “image”. To do this, you just need to divide the picture on the monitor perceived by our eyes into two pictures, but specifically for the right and left eyes, and these pictures will differ from one another only by the angle of rotation relative to the user.
These pictures are required show at the same time, on the same screen, where they will overlap one another. And in order for the viewer to perceive them as a whole and look at the same time “in two eyes”, you need to put on him special multi-colored glasses, in which each eye perceives only the picture that is intended for it.
This technology is theoretically quite simple. The equipment for it, in addition to penny glasses, is not required. But whoever wants to create programs, games and films for such glasses should know that this is a very laborious and complex process. Therefore, all over the world there are only a couple of dozen games and encyclopedias created for multi-colored "virtual" glasses.
Later, another method appeared artificial division of the picture using the hardware of the PC itself. A small amount of "phase shift" is needed to create a copy of the picture on the screen. This copy, slightly rotated in relation to the original, is fed along with the original to the screen at the right moment, and the “three-dimensional” picture is ready, mind you, practically without the participation of a complex program. In this way, any toy can be “trimmed”, even if it knew absolutely nothing about “virtual reality”!
Then cheap plastic glasses were replaced by two small LCD monitors - one for the right, the other for the left eye, and they were moved closer to the eyes, at a distance of several centimeters, which, mind you, is very tiring for the eyes and causes a headache.
It is on this principle thundered 5 years ago was created "virtual reality helmet", which is still sold in a number of computer companies at a price of 500 to 700 dollars. There is another, perhaps optimal, both in terms of price and quality, the technology of "virtual reality" - liquid crystal glasses. By themselves, such glasses do not show anything. And they can only alternately cover either one or the other eye with special liquid-crystal "barriers". This process occurs at a high speed - and in parallel to it, pictures for the left and right eyes are fed to the monitor screen. In this case, a special device is engaged in the “breakdown” of a regular image, which is installed between the video card and the monitor.
The only drawback of this method- the frequency of the vertical scan of the image you see is halved due to the alternate display of the picture, which means that only the best monitors will “pull” the frequency of 120 Hz in the 800 x 600 mode. The last “squeak” of spectacle fashion is the so-called "virtual monitors". Behind this loud name are already familiar “glasses” with liquid crystal displays, in the arms of which solid headphones are inserted that imitate high-quality sound.
Lesson topic. Printers: classification, characteristics and principle of operation.
1. Printers - devices for outputting text and graphic information from a personal computer to paper.
In modern printer models, it is possible to output information not only to paper, but also to another kind of media, for example, synthetic film.
Printers- a rather extensive class of devices, including up to 1000 different modifications. To somehow determine the characteristics, printers are classified by:
color (color and black and white);
· printing speed (this parameter is measured in the number of printed characters per unit of time). For modern printers, this parameter can reach several thousand characters per second;
By resolution (this parameter reflects the ability of the printer to display small lines and dots and is measured by the maximum number of lines, the length of which is equal to their width, per square centimeter or inch). For modern printers, this parameter can reach several
thousand dots per inch (dpi - inch per pixel);
By the width of the printer carriage (this parameter reflects the maximum possible document format);
By printing methods (shock and unstressed);
on the formation of output information when printing: sequential - the document is formed character by character, parallel (linear) - the entire line is formed at once, and page - the image of the whole page is formed;
· for printing images on paper: letter, matrix, thermal, inkjet, laser.
All printers, as a rule, work in two modes: text and graphic.
In text mode, codes of characters that need to be printed are sent to the printer from the computer. Printers support the most common fonts and their varieties.
When printing, it is possible to choose one of four quality modes for the resulting image:
Draft print mode (Draft);
Near-print mode (NLQ);
Printer-quality print quality (LQ) mode;
Super Quality Mode (SLQ).
Switching operating modes, depending on the type of printer, can be carried out both in software and in hardware, by pressing the buttons available on the printers.
In graphics mode, codes are sent to the printer that determine the sequence and location of image dots. Modern printers in graphic mode, due to the pseudo-graphic symbols they have in their memory, make it possible to implement service printing modes (dense, double-width, two-pass printing, multi-color printing, etc.).
