Information input devices are: Alternative input devices. Questions to Consider
1. Keyboard. 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 software. The keyboard driver is usually supplied with the operating system. This program allows the user to select the alphabet and implement the key layout.
All keys can be divided into the following groups:
Alphanumeric keys;
Cursor keys;
Special control keys;
Function keys;
Additional keyboard.
| Home | Move the cursor to the first position of the line |
| End | Move the cursor to the last position of a line |
| PgUp | Move through text towards the beginning of one page (usually 25 lines) |
| PgDn | Move text forward one page towards the end of the text |
| Ins | Switching the keyboard from replace mode to insert mode and back |
| Delete | Deleting the character indicated by the cursor on the screen |
| Esc | Cancel any actions or exit the program |
| Ctrl | |
| Alt | Used with other keys, changing their actions |
| Enter | Key for entering information and carriage return, used to complete the entry of the next line |
| Backspace | Move back one screen position to the left, deleting the previous character |
| Tab | Moving the cursor to the right by the number of positions specified on request or, predetermined by the program, moving |
| Shift | Case change key |
| Print Screen | Printing information displayed on the screen |
| Caps Lock | Fixing uppercase/lowercase letters |
| Num Lock | Fixing the operating modes of the small numeric keypad |
| Scroll Lock | Switching the display mode |
| Pause/Break | Interrupting (pausing) the execution of programs and procedures, such as displaying information on the screen |
Function keys F1-F12 are located at the top of the keyboard. These keys are designed for various special actions; they are programmable and have their own purpose for each software product.
2. Manipulators. Mouse manipulator- a device for entering commands, which is small device with multiple keys. Moving the mouse pointer across the screen is done by moving the mouse across the table. There are mechanical, optical and wireless devices. The mechanical device consists of a rubber ball that rotates when the mouse moves, and two mutually perpendicular rollers. The roller rotation sensors transmit signals to the computer. The “tail” of wires through which signals travel gives the device the name “mouse.” Electronic devices movements use the principle of processing reflected light pulses from the surface on which the mouse moves. Such devices are much more reliable than mechanical ones. Mice are produced that transmit information to the computer via an infrared channel (wireless). The characteristic of a mouse is resolution. It 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. The ballistic effect is the dependence of the accuracy of mouse positioning on the speed of its movement. 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.
Joystick– control device in computer games Oh. 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.
Light pen– one of the tools for entering graphic data into a computer. 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 manipulator - to perform additional operations and enable additional modes.
3. Scanner– translation device graphic information to digital. The function of a scanner is to obtain an electronic copy of a document created on paper. 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 are hand-held and desktop (portable page or sheet-fed, flatbed, slide scanners, drum scanners); they can be black and white (up to 64 shades of gray) and color (256 - 16 million colors).
Handheld scanners resemble a “mouse” in appearance big size, which the user moves across 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.
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 from individual sheets, as well as 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 system automatic feeding paper ensures uniform scanning across the entire width of the sheet.
Slide scanners are highly specialized devices designed to capture images from transparent material (photographic film) with high resolution and image quality. They have a pronounced professional orientation and high cost.
Drum scanners are professional stationary devices designed for use in printing and scanning large-format images. The main advantages are high scanning speed and accuracy due to a permanently fixed scanning element and high uniformity of rotation of the drum with the scanned image placed on it.
The main characteristics are:
Resolution (optical resolution), that is, the number of recognizable dots (pixels) per inch;
Scanning speed is a performance indicator that is equal to the time spent processing one line of an image;
Dimensions of the scanned sheet (scanning area);
Bit width - determines the maximum number of colors or shades of gray that the scanner can perceive.
The scanner driver is designed to control the scanning process and configure basic scanner parameters. Sometimes drivers are supplemented with means for manipulating scanned images (change brightness, contrast, etc.). Scanners can be used to easily transfer images (photos, drawings, etc.) into computer memory or onto a display screen, or for quickly entering text documents. In the second case from graphic image it is necessary to select (recognize) letters, numbers, spaces, tabs, columns, that is, convert the image into text format. Optical character recognition programs are designed to convert scanned texts into text codes.
4. Touch devices. Digitizer(graphics tablet) 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:
The working area is usually equal to one of the standard paper formats (A7-A0);
Resolution – step of reading information;
The number of degrees of freedom describes the number of characteristics of the relative position of the tablet and the 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(touchpad) is a pointing input device, most often used in laptops. Touchpads work by measuring the capacitance of your 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.
12. Types and purpose of information input and output devices.
Keyboard(keyboard) – a traditional device for entering data into a computer.
Joystick is a control stick and is most often used in computer games. Designed to enhance realism during a simulation game of a car, airplane, spaceship, etc.
Touch manipulator.
Scanner
Mouse
Light pen
Since the user often needs to enter computer system new information, input devices are also needed.
Printer
To obtain information about the results, it is necessary to supplement the computer with output devices that allow them to be presented in a form accessible to human perception. The most common output device is monitor, capable of quickly and efficiently displaying both text and graphic information on its screen.
Microphone is a device for inputting audio information: voice or music.
A plotter, or plotter, is a drawing machine that allows you to draw complex large-sized graphic images with high accuracy and speed: drawings, diagrams, maps, graphs, etc.
Modem
Network card (or LAN card) serves to connect computers within one enterprise, department or room located at a distance of no more than 150 meters from each other.
13. Types and purpose of peripheral devices of a personal computer.
Peripherals– these are any additional and auxiliary devices that are connected to a PC to expand its functionality. Input devices
(keyboard, mouse, trackball, joystick, scanner, microphone, etc.)
Trackball (trackball)- this is a ball located along with the buttons on the surface of the keyboard (an inverted mouse).
The pointer moves around the screen by rotating the ball.
Touch manipulator. It is a mousepad without a mouse. In this case, the cursor is controlled by simply moving your finger across the mat.
Digitizer (graphics tablet) Allows you to create or copy drawings. The drawing is made on the surface of the digitizer with a special pen or finger. The results of the work are displayed on the monitor screen.
Scanner- a device for entering information into a computer from paper. Scanners come in flatbed, desktop and handheld types.
Mouse- information input device. Converts mechanical movements on the table into an electrical signal transmitted to the computer.
Light pen- with it you can draw pictures and write handwritten texts that immediately appear on the screen.
Output devices
(monitor, printer, plotter, speakers, etc.)
Monitor- the main peripheral device for displaying information visible to a computer.
Modem- a device for connecting computers to each other over long distances via a telephone line. Using a modem you can connect to the Internet.
Printer- a device for displaying information on paper. Printers can be matrix (ink ribbon), inkjet (ink cartridge), laser (cartridge with toner powder).
Microphone-audio information input device: voice or music.
Plotter, or plotter, is a drawing machine that allows you to draw complex large-sized graphic images with high accuracy and speed: drawings, diagrams, maps, graphs, etc.
Personal computers have really become widespread relatively recently. Today, a PC or laptop is perceived as essential Appliances, and the level of awareness of users about the basics of their work is negligible.
Simply put, many modern “users” are perplexed by the simplest questions that once did not cause any excitement. For example, what is a primary input device? This term looks scary, it can have several interpretations at once, and therefore needs more detailed analysis and comments. However, that is why this article was created.
Basic Concepts
It is known that the processor of any computer has many input/output ports through which the “stone” exchanges data with peripheral devices. However, let's correct ourselves: some ports are really intended for exchanging information with peripherals, but many are necessary for contacts with a variety of internal hardware (video card, RAM etc.). The latter play a particularly important role, since without them the normal functioning of the machine is simply impossible. However, school computer science talks about all this. Input devices also work through ports.
What are they?
You should know that ports are divided by type. They are parallel (better known as LPT1-LPT4), as well as serial asynchronous (designated COM1-COM3). It should be noted that the first category has already sunk into oblivion: these ports were faster, but had a lot of operational difficulties. In addition, the COM variety is available not only in a physical form (connector), which almost no one uses anymore, but also in the form of a “virtual” port. In particular, USB modems, printers and similar peripherals are connected through them.
But the main port today is USB. They are very fast (especially the latest specifications) and provide seamless interaction with a huge number of devices.
Why did we tell all this?
How does all of the above help us understand what a basic input device is? The whole point is that you should have a rough idea of the ways in which this very device exchanges data with the computer. Now that all the “formalities” have been settled, it’s time to proceed to the main topic of our article.
Input devices are those designed to “translate” human languages or gestures into machine code that a computer can understand. Therefore, information input devices are:
- Keyboards and similar input devices.
- Scanning technology.
- Cameras and video cameras (digital, of course).
- Microphones.
- Mice, trackballs.
- Touch input devices.
Keyboards
Do you know the most basic input device? A keyboard is a device for entering text and numbers, the basis of which are keys. In addition, it can be used to send certain coded signals (hotkeys). There are also devices that have additional keys. As a rule, the latter serve for some specific multimedia functions, and they can (often) be assigned independently.
Despite all the efforts of touch screen adherents, the keyboard is the main information input device. It is simple, does not require special skills to learn, and allows you to communicate information to the computer in any existing human language. It is possible that with the development of technology something more convenient and universal will be invented, but so far this is far from happening. Today, keyboards are a mandatory input device on any computer equipment.
If you list input devices but forget about the keyboard, you will receive a failing grade.
Manipulators (mice, touchpads, trackballs)
These devices are most often connected to the serial port of a computer. To control the computer, a cursor is used that moves across the monitor or display in synchronization with the movements of the mouse or finger on the touchpad. Almost all devices of this kind have buttons that are used to fix a specific cursor position. These devices are divided into two categories - relative and absolute.
Until recently, almost all manipulators came with their own set of drivers, but today this one only applies to gaming mice, which has a huge number of additional keys, to which macros independently written by the user can often be “tied”.
Mice
Despite all of the above (regarding keyboards), many users are inclined to think that the main information input device is the mouse, which in ancient Soviet times was called a “kolobok”. invented it wonderful device back in the 70s of the last century, so mice are only slightly younger than keyboards.
It is safe to say that you will not be able to work in a Windows OS system without it: the user will instantly get bogged down in dozens of windows and submenus. With Linux the situation is somewhat different, since there almost everything can be done from the console, but with graphic editors Without a mouse, you won't be able to do anything meaningful. Not long ago, there was a widespread classification according to which “rodents” were divided into models with two and three keys. Today, this method of typing is clearly outdated: classic three-button mice are found only in museums and organizations with very limited funding. Gaming models can have 20 (!) buttons, and in place of the third key today there is almost always a wheel.
As we have already said, the functional purpose of the buttons can be changed. In addition, today you can find many utilities that greatly simplify such actions. It is generally accepted that the main indicator of the quality of a mouse is its resolution, which is measured in dots per inch (DPI).
Classification of mice
- Mechanical devices designed to input information. Today they practically never occur. A distinctive feature of such a mouse is a rubberized ball located at the bottom of the mouse. Older users remember very well that in order to position the cursor normally they had to frequently wipe it with alcohol. In addition, if there were cats or dogs in the house, the mechanism often jammed due to hair getting into it.
- Optical-mechanical varieties. In principle, the design contains the same ball, but its movement is monitored using control LEDs.
- The cursor movement is controlled only by LEDs. The light they emit performs the functions of the same ball.
- Wireless mice. The signal to the computer is transmitted not over a wire, but through an infrared port or “Blue tooth”.
Touchpad
The touchpad evolved from the trackball. The latter was a “reverse mouse”, when the cursor was controlled by only one ball. The touchpad is built on a slightly different principle, when the cursor moves following the movement of the fingers along the touch surface.
Here again we should make a digression and again mention trackballs: unlike mechanical mice, such devices are still used in some varieties computer equipment, as they ensure ideal cursor positioning.
Unlike mice, touchpads in most cases are quite primitive: equipping them with additional keys (and not just the “right” and “left” buttons), as well as a scroll bar, is entirely up to the manufacturer. Until recently, touchpads were not very popular with people whose profession involved typing and similar work, since the number of false positives (from light touches of the hands) was prohibitively large. Modern models are almost completely free from this drawback.
Scanning technology
Scanners are needed to convert images, photographs, texts and drawings into digital format. They are indispensable in archives and libraries, where there is often a huge amount of work involved in digitization. Simply put, such devices input graphic information.
Scanning equipment can be hand-held (such a device is very reminiscent of reader scanners in supermarkets), roll-based and flatbed. Sometimes you come across projection models. Again, in the above-mentioned archival institutions it is not so rare to see slide scanners designed for digitizing filmstrips. Like mice, this technique is rated by the number of pixels per inch, only in this case the DPI characteristics are decisive: a scanner with poor performance can turn even high-quality text on completely white paper into an unreadable “mess”.
Digital photos and video cameras
Oddly enough, digital cameras are also considered input devices. However, there is nothing unusual about this: such cameras and video cameras convert images and video into “digital”, which is so dear to computer processors. Unlike scanning, this approach leaves no room for errors and interference, allowing you to immediately begin processing high-quality materials in graphic editors.
As a rule, connecting the camera itself to a computer requires a whole package of drivers, which the manufacturer supplies with the device. However, such complications are not needed so often: it is enough to remove the memory card and read information from it directly.
Microphones
A microphone is a device that converts information into electrical (or digital) impulses that a computer can understand. The scope of use is incredibly wide: they are used not only in theater and television, but also in science. Particularly sensitive microphones can even pick up the sound of growing grass, so scientists use them very actively.
As we have already said, the principle of operation is the transformation of acoustic vibrations. Since there are many obstacles along this path in the form of numerous interferences and inaccuracies in coding, a high-quality microphone must meet a number of mandatory requirements:
- The microphone's own level of electrical noise should not interrupt the recorded acoustic signal. This is especially true for sensitive scientific models.
- The resulting recording must contain a minimum amount of distortion.
- All acoustic information must be transmitted practically without distortion, which practically eliminates the use of wireless communication channels (possible interference) in particularly complex equipment of this class.
There are many types of microphones, but today you can most often find semiconductor and electrostatic models. This audio input device allows you to provide the highest quality sound.
Touch devices
In recent years, this technology has developed to its full potential. Almost every second first-grader has smartphones with touch controls, so it doesn’t make much sense to explain all the advantages and disadvantages of this technology. Therefore, we will focus on describing devices that are actively used today.
Digitizer
So, information input devices include digitizers. This device is designed for entering graphic information, and therefore has received particular recognition among professional designers and artists. As a rule, these devices are made in the form factor of well-known tablets. That’s why they are often called graphics tablets.
They are constantly used in computer graphics, animation and development of three-dimensional models. Let us immediately note that just in the case of constructing complex geometric models A digitizer is far from the best solution. But for artists, in most cases it is indispensable. What other information input devices of this type can still be found in a professional environment?
Touch displays
Touch screens, as we said above, are extremely common today. In the thickness of such a display there are many sensors that track the location of the finger in real time. The controller processes the received information and sends it to the processor for final processing.
Benefits of touch screens
Theoretically, you can do without a mouse and keyboard. But if this is true in relation to mice, then long-term use of a touch keyboard can make any fingers beg for mercy. What’s more important is that even older people, for whom using a mouse was akin to sophisticated torture, can easily get used to the same tablets.
In some industries and in medicine, such screens are sometimes the only right choice, since they can work in an aggressive environment (they can easily be protected from moisture and other factors by placing them in a case). In addition, today many especially durable varieties have been created (for terminals and ATMs) that can work in public places. What is the name of the information input device, which is often used in conjunction with graphics tablets?
Light pen
Another type of manipulator. At first glance, it looks like an ordinary pencil or ballpoint pen connected with a wire to a computer. To adjust parameters on the pen there are several buttons, the functionality of which allows you to flexibly “tailor” the instrument to a specific situation. The pen tip has a photocell that performs the same function as its “colleagues” in a conventional optical mouse. Currently, such a technique is found only as an element of digitizers. Of course, light pens are most widely used among professional artists and designers.
These devices allow you to create an almost reliable simulation of using a regular pencil, which is extremely important for many specialists.
Conclusion
Simply put, any input devices text information, graphics or sound are not only indispensable assistants for any user, but also tools that allow us to work productively with the computer. Without the same keyboard, you are unlikely to be able to do anything worthwhile without spending an unreasonable amount of labor resources.
Currently, work is quite actively underway aimed at creating new input tools. Some devices turn out to be relatively successful, while others are left to wait in the wings. Be that as it may, this process does not stop, and therefore it is possible that our grandchildren will already remember some of the devices listed in the article as a terrible anachronism.
The PC processor contains ports through which it communicates with external devices I/O
Definition 1
Input devices- These are devices that convert information from a form understandable to humans into a digital form that is perceived by a computer.
Keyboard
The most important and almost irreplaceable device for entering information into a PC is the keyboard, which is considered one of the main components of a PC.
Definition 2
Keyboard is a device for entering numerical and text information, as well as computer control, which contains a standard set of keys and additional keys - control, function keys, cursor control keys and a small numeric keypad.
Picture 1.
Pointing (coordinate) input devices
Devices that are used to directly enter information by indicating a command or location for data entry with a cursor on the monitor screen. Using these devices, the user moves the cursor or other program objects across the two-dimensional space of the monitor screen.
Such input devices form a group of manipulators.
Computer mouse
Computer mouse is a traditional input device and allows you to move the cursor across the monitor screen synchronously with moving the mouse on the table.
Using the mouse keys, you can specify one or another type of operation with an object. The main characteristic of a mouse is its resolution, which is measured in dots per inch.
The variety of manipulators has been amazing lately.
Based on the type of device and method of functioning, mice are classified into:
- Mechanical - today their production has been discontinued.
- Optical-mechanical.
- Optical.
- Infrared.
Figure 2.
Trackball
Trackball resembles a mouse “in reverse”, i.e. the device itself remains stationary, and the cursor movement is controlled by rotating the ball, which is located at the top of the trackball. At the same time, such control allows you to position the cursor more accurately. Trackballs are used mainly when working with graphics packages, packages for computer-aided design and so on.
Figure 3.
Touchpad
Built-in manipulator for laptop PCs, the cursor is moved by touching the touchpad with your fingers. It is an alternative to a mouse in laptops.
Gaming input devices
Joystick
A manipulator for controlling computer games, made in the form of a lever on a stand that can be tilted in two planes. In addition to computer games, it is used in training programs and educational simulators.
Figure 4.
Gamepad
Manipulator for computer games. Made in the form of a remote control, which is held with two hands and controlled with the thumbs.
Figure 5.
Computer steering wheel
A device that simulates a car steering wheel for playing a car simulator (computer game).
Dance platform
A flat panel input device designed for use in dance games.
Light gun
A device intended for use in television game consoles, which allows you to “shoot” at the TV screen with a “hit-and-miss” result.
Touch input devices
Made in the form of sensitive surfaces, coated with a special layer and connected to the sensor. The cursor is driven by moving your finger across the sensor surface.
Touch screen or touchscreen
It is an integral part of any sensory device or equipment. Made in the form of a glass or plastic plate, which is specially attached on top of the monitor screen or built inside the case. Sensors connected to the plate collect information from the surface of the screen. The controller, which comes complete with a touch screen, processes the information received from the sensors and transmits it to the PC.
Usage touch screen autonomous from other input devices. Provides the user high speed control, reliability and resistance to harsh external influences.
Figure 6.
Light pen
A type of manipulator for entering graphic data into a PC. Made in the form of a ballpoint pen or pencil, which is connected by a wire to one of the PC I/O ports.
Data input involves touching or drawing lines with a pen on the surface of the monitor screen using a photocell mounted on the end of the pen, which registers changes in screen brightness at a point. Often a light pen comes with a graphics tablet (digitizer).
Used in pocket PCs, design and design systems.
Figure 7.
Graphics tablet (digitizer)
Made in the form of a tablet. It is used for point-by-point coordinate input of images in automatic design systems, computer graphics, animation and handwritten text in a PC. Can be used to input finished paper images into a PC.
Figure 8.
Other input devices
Scanner
A device for converting graphic data (texts, pictures, slides, photographs, drawings) into digital ones.
They are classified according to the method of moving the reading head and the image relative to each other: manual, roll, flatbed and projection. Slide scanners are a type of projection scanners.
Figure 9.
Digital photo and video cameras
Instead of film, a special memory element is used that stores photo or video data transferred from the lens in the form of uncompressed or compressed file with subsequent transfer to a PC.
Figure 10.
Microphone
A device for converting sound vibrations into electrical vibrations, connected to the input of the sound card. Used in telephones, radios, television systems, sound reinforcement and recording systems.
Webcam
A small digital photo or video camera that is capable of capturing images in real time for subsequent transmission over a computer network.
Figure 11.
The list of devices for inputting information into a PC is not limited to the above elements, the variety of which never ceases to amaze.
Keyboard
Nowadays, the main widespread device for entering information into a computer is the keyboard (keyboard device). It implements interactive communication between the user and the PC:
Entering user commands to provide access to PC resources;
Recording, adjusting and debugging programs;
Entering data and commands in the process of solving a problem.
The MFII keyboard standard has now been adopted. Conventionally, we can distinguish five groups of keys that carry their own functional load:
· a group of alphanumeric keys is intended for entering character information. Each key can operate in several modes (registers) and, accordingly, can be used to enter several characters;
· group function keys(from F1 and F12) defining. Functions operating in this moment programs:
· service keys: Shift, Enter, Ctrl, Alt, Tab, Esc, Back space, Print Screen, Scroll Lock, Pause/Brear;
· two groups of cursor control keys. A cursor is a screen element that indicates the location for entering character information. One group, the arrow keys, moves the cursor in the direction indicated by the arrow. The other has the following keys: Page Up/Page Down – moves the cursor one page up or down.
Home and End – move the cursor to the beginning or end of the current line.
Insert – switches insertion and replacement modes.
Delete – designed to delete characters located to the right of
current cursor position;
· a group of keys on a small numeric keypad or additional panel is mainly intended for entering numbers. However, they can also duplicate cursor control keys. The transition from one mode of their use to another is carried out by pressing the Num Lock key.
This classification is strictly conditional, since in reality, depending on the program being executed, almost any key can perform both functional and service duties, and can also be blocked by the program. Therefore, the description of each software product must have a section outlining the functions of the keyboard.
Mouse
It is used to enter data or single commands selected from menus or text messages of graphical shells displayed on the monitor screen.
The mouse is connected to the computer using a special cord and requires special software support.
To operate the mouse, you need a flat surface; for this purpose, rubber mats (Mouse Pad) are used.
Because you cannot enter a series of commands into the computer using a mouse. Therefore, the mouse and keyboard are not interchangeable devices. The purpose of graphical shells is to provide initialization of many commands without lengthy typing of them from the keyboard. This reduces the likelihood of typos and saves time. On an object in the form of a textgram, a menu item or symbol is selected and initialized by clicking the mouse button. Of course, when typing or performing certain functions, using the mouse may be irrational if, for example, these functions are performed by pressing function keys.
Currently there is also optical mouse, where the signal is transmitted using a mouse beam to a special pad and analyzed electronically. While the tailless (cableless) infrared mouse is less common (the principle of its operation is similar to the operation of remote controls remote control) and radio mouse.
Trackball
In portable PCs (Lapton, Notebook), the mouse is usually replaced with a special ball built into the keyboard on a stand with two keys on the sides, called a trackball.
The principle of its operation is the same as the principle of the mouse. Despite the presence of a trackball, a laptop PC user can also use a regular mouse.
Joystick
Hand-held manipulators also include a joystick, which is a movable handle with one or two buttons that have the same purpose as the mouse keys.
This input device is most common in the field of computer games. IN game consoles Digital joysticks are used, while computers use analog joysticks. An analog joystick has many advantages over a digital joystick, the most important being greater control accuracy and the absence of the need to use a special card and adapter to connect to a computer.
Light pen
To enter drawings into a PC, a so-called light pen can be used. It is used relatively rarely, since it is suitable for working with large objects, but is very unreliable when selecting small objects.
The light pen was further developed with its sharing with a digitizer (digitizer), where you simply write with a pen, then special programs convert the handwritten text or drawing into a digital code. Professional light pens can determine line thickness, pen pressure, and other parameters.
Digitizer
Is the standard input device for professional graphic works. By using software hand movement is converted into vector graphics format. The digitizer is capable of determining and processing absolutely precise coordinates, which is inaccessible to other input devices.
Scanner
Optical scanners are used to directly read graphic information from paper or other media into a PC. The scanned image is read and converted into digital form by elements of a special device: CCD chips. There are many types and models of scanners. Which one to choose depends on the tasks for which the scanner is intended. The simplest scanners recognize only two colors: black and white. These scanners are used to read bar codes.
Handheld scanners - the simplest and cheapest. The main disadvantage is that the person himself moves the scanner around the object, and the quality of the resulting image depends on the skill and steadiness of the hand. Another drawback is the small scanning bandwidth, which makes reading wide originals difficult.
Drum scanners used in professional printing activities. The principle is that the original on the drum is illuminated by a light source, and photosensors convert the reflected radiation into a digital value.
Sheet scanners. Their main difference from the previous two is that during scanning, a ruler with CCD elements is fixedly fixed, and the sheet with the scanned image moves relative to it using special rollers.
Flatbed scanners. This is the most common type for professional work today. The object to be scanned is placed on a glass sheet, the image is read line by line at a uniform speed by a reading head with CCD sensors located at the bottom. The flatbed scanner can be equipped with a special slide attachment device for scanning transparencies and negatives.
Slide scanners used for scanning micro images.
Projection scanners. A relatively new direction. A color projection scanner is a powerful multifunctional tool for inputting any color images, including three-dimensional ones, into a computer. It can easily replace a camera.
Nowadays, scanners have another application - reading handwritten texts, which are then special programs character recognitions are converted into ASC II codes and can subsequently be processed by text editors.
Digital camera
A digital camera is used to input video images into a computer.
The operating principle is similar to that described for scanners. Although the camera has photo optics similar to those of a camera, there is no need for photographic film, just like a projection scanner. The image scanned by the camera is immediately received and converted into digital form. Rapid progress and reduction in prices for related equipment are expected in this area.
Microphone
Used to input audio information (speech) into the computer. Microphones come in two modifications - attached to headphones and independent devices. The entered information is saved as sound files.
Related information.