Introduction to Computers Lecture # 5
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The document provides an overview of computer hardware and input devices. It discusses the basic components of a computer system including the input, processing, storage and output units. It then describes various commonly used input devices such as keyboards, mice, scanners, microphones, webcams and touchscreens. Specific input devices like optical mark readers, bar code readers and digitizers are also explained along with their uses.
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Introduction to Computers Lecture # 5
- 1. Introduction to Computer Lecture # 5 Course Instructor : Sehrish Rafiq Govt. Girls Degree College Maneri Swabi Higher Education Department KP
- 2. LectureOverview • Computer Hardware • Organization of a computer system • Input Devices
- 3. ComputerHardware • The physical components of a computer system are known as hardware. • Hardware refers to machines in computer system. • Those components of a computer system which can be seen, touched and felt are known as hardware. • The mechanical and electrical components of a computer system are known as hardware.
- 4. Organizationof a ComputerSystem • Every digital computer is made of four basic units. Input Unit Central Processing Unit Storage Unit Output Unit
- 5. Responsibilitiesof Input Unit • It accepts or reads instructions or data from outside world. • It converts these instructions and data in computer acceptable form(machine language). • It supplies the converted instructions and data to the computer system memory for further processing.
- 6. Responsibilitiesof ProcessingUnit • Execution of program instructions • Control other units of computer
- 7. Responsibilitiesof Output Unit • It accepts the results produced by the computer which are in coded form (machine language) and hence cannot be easily understood by humans. • It converts these coded results in to human understandable form. • It supplies the converted results to outside world.
- 8. Responsibilitiesof StorageUnit • Store data and instructions required for processing (received from input devices). • Store intermediate results of processing. • Store final results of processing before they are released to an output device.
- 10. Commonlyused input devices • Keyboard devices • Point and draw devices • Data scanning devices • Digitizer • Electronic cards based devices • Microphones • Webcams • Speech recognition devices • Vision based devices
- 11. KeyboardDevices • Allow entry in to a computer by pressing a set of keys (labeled buttons) neatly mounted on a board connected to a computer system. • 101-keys QWERTY keyboard is most popular. • In laptops the keyboard buttons are mounted in the machine and are not on a separate board, therefore it is called keypad.
- 12. KeyboardDevices
- 13. Point & DrawDevices • Used to rapidly point to and select a graphical icon or menu item from multiple options displayed on the screen. • Used to create graphic elements on screen such as lines, curves and freehand shapes • Examples: Mouse Track ball Joy stick Light pen Touchpad Touch screen
- 14. Mouse • It is a hand-held pointing device that detects two- dimensional motion relative to a surface. • This motion is typically translated into the motion of a pointer on a display, which allows a smooth control of the graphical user interface. • Types of mouse Mechanical mouse Optical mouse
- 15. TrackBall • It is a pointing device which consists of a ball held by a socket containing sensors to detect a rotation of the ball about two axes. • It is like an upside-down mouse with a ball that sticks out. • The user rolls the ball with the thumb, fingers or the palm of the hand to move a cursor. • Applications General Purpose Computers Radar consoles in an air-traffic control room Sonar equipment on a ship or submarine
- 16. Joy Stick • A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. • Joysticks are often used to control video games, and usually have one or more push-buttons whose state can also be read by the computer. • It performs the same function to the arrow keys in the keyboard but they provide eight direction movement. • Applications Video games Controlling flight of an aircraft controlling cranes, trucks, underwater unmanned vehicles
- 17. Light Pen • A light pen is an input device which looks like an ordinary pen but its tip is a contains light sensitive detector. • It is used in conjunction with a computer's CRT display. • When its tip touches the screen, the computer locates its position in the form of X-Y coordinates. • • It allows the user to directly point to displayed objects or draw on the screen in a similar way to a touchscreen but with greater positional accuracy.
- 18. Touch pad • A touchpad is also known as a track pad. • It is a pointing device which contains a tactile sensor. • It is a specialized surface which can translate the motion and position of a user's fingers to a relative position on screen. • It is a common feature of laptops and is used as a substitute for a mouse where desk space is scarce. • Because they vary in size, they can also be found on personal digital assistants (PDAs) and some portable media players. • Wireless touchpads are also available as detached accessories.
- 19. Touch Screen • A touchscreen is a computer screen that can be used by touching it with a finger or a stylus pen. • It enables the user to interact directly with what is displayed. • It can be described as a touchpad with a screen built-in to it. • Today, all kinds of devices, both big and small, make use of touchscreens. • However, tablet computers and smartphones have made them popular and are the most widely known and used products that use touchscreens.
- 21. • Input devices that enable direct data entry in to a computer from source document are known as data scanning devices. • They eliminate the need to key in text data in to computer. • Due to reduced human effort in data entry, these devices improve data accuracy and increase the timeliness of information processed. • They demand high quality of input documents. • Some of them are capable of recognizing marks or characters. • Examples: • Image Scanner • Optical mark Reader • Bar Code Reader • Magnetic Ink Character Reader DataScanning devices
- 22. • Scanner translates paper documents in to electronic format for storage in computer. • Electronic format of a scanned image is its bitmap. • Stored image can be altered or manipulated using image processing software. ImageScanner
- 23. • It is a scanner equipped with a character recognition software. • It photo-scans text character-by-character, analyzes the scanned-in image, and translates it into character codes. • It utilizes light beams to read alpha numeric characters of both hand written or typed text. • It is extremely complex because it is difficult to make computer recognize an unlimited number of fonts. • They are used for large volume processing applications such as scanning of utility bills of customers etc. OpticalCharacterRecognition(OCR) Device
- 24. • It is a scanner capable of recognizing a pre-specified type of mark by pencil or pen. • It can capture human-marked data from document forms such as surveys and tests. • They are used to read questionnaires, multiple choice examination paper in the form of shaded areas. OpticalmarkReader
- 25. • A bar code reader is an electronic device that can read data in the form of bars/lines known as Universal Product Code (UPC) in to the computer. • UPC contains the detailed product information and is used for labeling goods and stock in a shop. • After detecting the code, it transmits the product data in to computer which locates item price, updates the stock and prints the receipt for the customer. Bar Code Reader
- 26. • MICR is a device capable of recognizing characters written with special ink and in specific font. • It is mostly used by banks for faster processing of large volume of cheques. • Numbers and characters (consisting of check number and account number) are printed using Magnetic Ink on bottom of cheques. • MICR provides a secure, high-speed method of scanning and processing information. • MICR supports only 14 symbols. MagneticInk CharacterReader (MICR)
- 27. Magnetic Ink Character Reader
- 28. • Digitizer is an input device used for producing pictorial images. • It enables the user to write/draw something on the tablet like surface using stylus. • The tablet senses where the stylus touched it and sends the x-y coordinates of each point to the computer. • It is mostly used by architects and engineers to design cars, buildings, medical devices, robots etc. • It is also used for digitizing maps available in paper form. Digitizer
- 29. • Electronic cards are small plastic cards having encoded data appropriate for the application for which they are used. • Electronic card reader is used to read data encoded on an electronic card and transfer it to the computer for further processing. • Used together as a means of direct data entry in to a computer system. • Used by banks for use in Automated Teller Machines (ATM’s) and organizations for controlling access of employees to physically secured areas. ElectronicCard Reader
- 30. Microphone • Microphone is an input device to input sound that is then stored in a digital form. • The microphone is used for various applications such as adding sound to a multimedia presentation or for mixing music.
- 31. Webcam • A webcam is a video camera that is used for capturing snaps or videos. • When "captured" by the computer, the videos/ pictures may be saved, viewed or sent on to other networks using internet or can be e-mailed as an attachment. • When sent to a remote location, the videos/ pictures may be saved, viewed or on sent there. • A webcam is generally connected by a USB cable or built into computer hardware, such as laptops.
- 32. SpeechRecognitionDevices • Input device that allows a person to input data to a computer by speaking to it is known as speech recognition device. • Today speech recognition devices are limited to accepting few words within a relatively small domain and can be used to enter only limited kinds and quantities of data. • Types of speech recognition devices • Single word Recognize a single word Speaker independent • Continuous speech recognition systems Recognize sentences Speaker dependent
- 33. Usesof speechrecognitionsystems • For inputting data to a computer by user in situations where their hands are busy or their eyes must be fixed on a measuring instrument or some other object. • For data input by dictation of long text or passage for later editing and review. • For authentication of a user by a computer system based on voice input. • For limited use of computers by individuals with physical disabilities.
- 34. Vision-Input Systems • Allow computer to accept input just by seeing an object. • Input data is normally an object’s shape and features in the form of an image. • Mainly used today in factories for designing industrial robots that are used for quality-control and assembly processes.