Input & Output Devices - Chapter 4 PDF

Chapter 4 Input & Output Key Topics Input & Output Concepts Text Input Point Input Visual Input Audio Input Visual Output Hardcopy Output Audio Output 2 Input & Output Concepts Data is commonly available in the form of text, point,...

Chapter 4 Input & Output Key Topics Input & Output Concepts Text Input Point Input Visual Input Audio Input Visual Output Hardcopy Output Audio Output 2 Input & Output Concepts Data is commonly available in the form of text, point, image, audio or video. Point data is used to work on objects shown on any screen. Data of all forms must be converted into bits for processing and storage. Input devices (and related software) convert text, point, image, audio or video into bits. Output devices (and related software) convert bits into different forms understandable to humans. 3 Input & Output Concepts 4  Text Input Keyboards Keyboard is an input device for text having keys arranged in typewriter configuration (QWERTY). › Can be used to input characters (letters, numbers and other symbols etc.) › Can be built-in as well as connected through ports, wires or wirelessly Text Input Keyboards Most Keyboards contain: › Standard alphanumeric keys › Numeric keypad › Function keys › Directional keys and special keys 6  Text Input Mobile devices also use: › On-screen keyboards which work with pen or touch › Slide-out keyboards › External keyboards built in cases or connected through ports 7 Point Input Pointing Device is an input device that moves a pointer (cursor, arrow or insertion point) to interact with objects on a screen. Often used to start programs, open files, move around content (scroll / swipe), edit documents (copy, cut, paste) and draw or edit images. Common types of pointing devices include:  Mouse  Electronic Pen / Stylus  Touch Enabled Screen  Touchpad, Tracking Ball, Joystick, Control Wheel 8 Point Input Mouse is the most common pointing device that a user slides on a flat surface to move a pointer on the screen. It is clicked to interact with objects.  Older mechanical mice use a ball.  Optical or laser mice track movements using light.  Touch mice do not have buttons or scroll wheels. They respond to two- dimensional gestures and taps.  Mice typically connect to a computer through a USB port or a wireless connection like Bluetooth. 9 Point Input Traditional Mouse vs. Touch Mouse Touch Mouse responds to swipes for scrolling and taps for clicking 10 Point Input Stylus is a pen-like pointing device used to draw or write electronically on the screen.  Also called digital pen, electronic pen, or pen.  Pen input is often used with mobile devices and tablets.  Can also be used with desktop and portable computers if the display screen supports it. 11  Point Input Touch Screens are display devices that are touched with a finger or stylus to select commands or otherwise provide point input to the computer.  Common on portable computers, smartphones, kiosks, Point of Sales systems and other devices.  Multi-touch screens can recognize input from more than one finger at a time. 12  Point Input Other pointing devices include: › Gaming Devices › Trackballs › Control Buttons and Wheels › Touch Pads 13 Visual Input Scanner (optical) is an input device that captures image of an object in digital form. It can scan photos, documents, images, etc. 14 Visual Input Common types of scanners: 1. Flatbed scanners (scan flat objects one page at a time) 2. Portable scanners (scan objects while on the go) , Eg. Doxie 15  Visual Input Common types of scanners: 3. 3D scanners (scan objects in 3D) 4. Task-specific scanners, such as receipt and business card scanners 16  Visual Input Biometric Readers are smart scanners used to input biometric data such as an individual’s fingerprint, retina, facial features or voice. Can be stand-alone readers or built into another piece of hardware. Most often used for access control, to authorize electronic payments, and to log on to secure web sites. 17  Visual Input Digital Cameras take pictures and record them in the form of digital images. › Primary appeal is that images are immediately available. › Camera quality is measured in Mega Pixels (MP). › Typically use flash memory for storage. Digital video cameras record videos in digital form. › Examples include Digital Camcorders, PC video cameras (PC cams), webcams etc. 18 Audio Input Audio can be of two types:  Voice narrations (like podcasts etc.) for which Microphone is used for input.  Sound from instruments (from MIDI keyboards etc.) which connect directly to the sound card. Speech Recognition System is a voice input system which enables a computer to recognize human voice and respond to it.  Can be used for dictation as well to as issue commands to a device.  Usually incorporated into smartphones, GPS systems and other mobile devices. 19 Visual Output Display Screens present output visually (text, image, video) on a suitable type of screen. Monitors are display devices typically used with a desktop computer. Display screens are built into a variety of devices like: › Notebook and other portable computers › Smartphones and mobile devices › Handheld gaming devices, home entertainment devices, kitchen appliances › Digital photo frames, e-book readers, smart watches, wearable glasses › Digital signage systems, digital billboards 20 Visual Output Display Screens have pixels (picture elements) which are illuminated to show text or images. › All colours shown on displays are made by mixing three basic colours which are Red, Green and Blue (RGB). Quality of a display screen is determined by: › Size of the screen measured diagonally › Resolution of the screen described by maximum number of pixels along the horizontal and vertical sides › Technology used to illuminate pixels like CRT, LCD, LED and OLED 21 Visual Output Data Projectors, also known as Multimedia Projectors, display output from a computer to a wall or projection screen › Often found in classrooms, offices, conference rooms and theaters › Can be wireless or integrated into devices › Some contain docks for smartphones 3D Projectors can show three dimensional output with special 3D glasses › 3D Projectors can also show holograms https://www.youtube.com/watch?v=4N0Ewb_OVsU Hardcopy Output Printers produce hard copy output on paper, cloth, metallic sheet or any suitable surface. › Common printers use liquid ink or toner. › Output can be coloured or “Black-and-White”. Printer quality is determined by:  Resolution measured in dots per inch (DPI).  300 DPI is suitable for general use, 1,200 DPI for photographs and 2,400 DPI for high quality prints used in marketing.  Print Speed measured in pages per minute (PPM) or images per minute (IPM). › PPM ranges between 10 to 65. 23 Hardcopy Output Connection options for printers include USB ports, wired networks, Wi-Fi or Bluetooth. › Personal printers connect directly to a single computer. › Network printers connect directly to a home or an office network and some can even perform Cloud Printing. Multi-Function Devices (MFDs) combine several functions like copy, fax, scan and print. Integrated printers are built into a smartphone, digital camera, etc. Large-Format printers print posters, maps, signs, blueprints, etc. 24 Hardcopy Output All colours shown on prints are made by mixing three basic colours which are Cyan, Magenta and Yellow. Black ink or toner is often provided separately as it is needed more often. Laser printers use toner (powder) and heat to produce output on paper or slides. Inkjet printers spray droplets of ink to produce output on paper or any supported surface. Laser printers are faster and produce better quality output while inkjet printers are cheaper. 25 Audio Output Speakers are the most common output device for audio output (voice, music, and other audible sounds). › Headphones and Earbuds also include small speakers. › Screen Readers use speakers and special software to provide audible version of data shown on a screen for those who are visually impaired. 26 Special Purpose Devices 3D Printers use plastic or other materials to form output in layers to build a 3D version of an object. https://www.youtube.com/watch?v=Llgko_GpX bI 27  Multi-Function Devices Some devices have both input and output functionality. Examples are: › Touch Screen Displays › Headsets and Earpods 28 Questions ??? 29