The document provides an overview of input and output devices used in human-computer interaction. It discusses various types of input devices like keyboards, mice, touchscreens, and their characteristics. It also covers different types of output devices such as computer screens, printers, speakers. The document aims to help users identify appropriate input/output devices for tasks based on factors like user abilities, task requirements, and environment.

21. Ergonomical Dvorak Keyboard Imran Zakir

22. Ergonomical Dvorak Keyboard - Zoom Imran Zakir

27. Special Keys and Facilities Device Cursor control keys “ Soft” function keys or control keys “ Hard” function keys Scroll bars and arrows Screen buttons Description Four keys with arrows showing the direction in which a cursor on the screen will move when the key is pressed Keys that are pressed in combination with other keys (e.g., <control>). Labeled keys that perform a specific function (e.g., <page down>). Characteristics of a window that enable the user to move the contents of a window up or down. Areas of the screen that perform a function on selection. Sometimes also called soft keys or soft buttons. Key Features/Remarks Used for moving around a screen display. Keys are programmed to perform an action. Good for commonly used functions, and for providing rapid execution of commands. Can be difficult to remember. No standard arrangement. Cursor keys and the <enter> key are examples. Less obscure than soft keys since they are usually explicitly labeled. Scrolling facilities can be provided through the use of cursor keys and function keys, or by clicking a pointing device such as a mouse on a scroll bar or arrow. Usually labeled boxes or circles. Can be pressed or clicked. Imran Zakir

28. Scanners as Input Devices Device Bar code reader Optical character reader (OCR) Document scanner Magnetic ink character recognition (MICR) Optical mark reader (OMR) Description Pen- or gun-like device that reads black and white printed or magnetic bar code. Can also be embedded under a counter. Device that reads characters automatically. High-speed scanner that reads whole pages. Device that interprets characters with the use of special ink. Device that detects the position of marks made on documents. Key Features/Remarks Suitable where the amount of data is limited, and is not subject to rapid change. Example: supermarkets. Can handle a variety of data. Characters need to be well formed (i.e., hand-written characters may be misinterpreted). Used for inputting large amounts of text, diagrams, and pictures. Similar to OCR, but more reliable. Used mostly in banks (e.g., see the bottom of your check book). Specially designed forms are required so that the marks are correctly located. Example: Course evaluation sheets Imran Zakir

30. Pointing Devices Device Dataglove Footmouse Gesture Devices Graphics tablet Joystick Description Wired glove that allows the wearer to grasp objects in 3D space. A form of pedal that pivots. Small transmitting device held by the user, employed together with a receiving device associated with the computer. Flat panel that is placed on a table near the computer display. The tablet surface represents the display. Small stick that can be moved in any direction within a fixed socket. Key Features/Remarks Used for manipulating objects and gesturing. Now being studied for virtual environments. The direction that the pedal is moved in causes a cursor on the screen to move correspondingly. Useful when hands are otherwise occupied or for physically challenged users. The receiving device places the position and movement of the transmitting device in space. Facial gestures may be used in combination with speech. Movement of a stylus across a surface causes a cursor to move across the screen or a line to be drawn. Very good for graphical input. Often used for cursor-positioning tasks where precision is required. Requires a high level of concentration to use. Fine control is limited. Imran Zakir

31. Pointing Devices (cont.) Device Light pen Mouse Pen and notepad Touch screen Trackball Digital Image/Video Description Pen that emits a light beam when a button is pressed. Continuous input device with one or more buttons for discrete input. Unlike the trackball or joystick, it is not fixed, so the user can move it around on a flat surface. A pen is used with a small electronic notebook. Data can be entered using familiar techniques involving menus, forms, etc. Special screen that detects the position of a finger touching it. Rotatable ball embedded in a surface in a fixed socket. Similar to a mouse turned upside down. Digital image or video camera. Key Features/Remarks Good for pointing and simple input. Has to be used against a vertical plane, not very accurate, difficult to use if grip is weak. Most common and popular. Highly versatile. May be tethered or wireless (radio, infrared); mechanical (rollers), optical (requires a special pad). Objects are manipulated by pressing control button(s) embedded in the mouse. Most impressive feature is ability to input free-hand drawings and handwriting. Must be taught to recognize hand writing. Some gesture recognition is possible. Stationary. Needs frequent cleaning. Very easy to use. Not very accurate Can be moved by drawing the fingers or the palm of the and over the surface or by flicking. Requires little force. Fast, and does not require a good grip for accurate use. Ability to capture images or video. Imran Zakir

37. Speech Recognition (cont.) Device Isolated word recognition (also known as discrete word recognition) Continuous speech recognition Speaker-dependent recognition (also known as speaker- trained recognition) Speaker-independent recognition Speaker-adaptive recognition Description Individual words Recognition of words within strings of words Recognition only for specific users Recognition for all users Combines speaker-dependent and speaker-independent recognition Key Features Limited vocabulary. Pauses between words. Users typically need some training. Less limited vocabulary, but works by recognizing words from a continuous stream of speech. More susceptible to error than isolated word recognition, but does not require special raining of users. System learns to recognize the speaker, who must train the system. Template matching. Easier to implement than speaker-independent systems, but highly sensitive to user characteristics (e.g., cold, different locations, etc.) Fairly large vocabulary. Based on phonemes. Many speech tokens needed. Problems with accents, non-native speakers. Requires arbitration between speaker-trained and speaker-independent recognition. Imran Zakir

38. Eye and Head Movement Device Electrophysiological sensing Photo-electric reflection Head movement tracking Description Records muscle movement. Records movements in reflected light from the eye. Lightweight headset, transmits ultrasonic signals to a special measurement unit. Key Features/Remarks Electrodes have to be secured to the skin to detect muscle movement, and are therefore subject to general body movement. Uncomfortable and confining. Not well suited for tracking over small target or where fine control is required. User must maintain a stable image on the fovea. Not easy to achieve or maintain. Not great for tracking small targets or where fine control is required. Keyboard is a display on the computer screen. The system detects slight movements of the user’s head and moves the cursor accordingly. To operate a key, the user must locate the cursor, and then blow on a blow switch in the headset mouth piece. This type of device can be used by severely handicapped users (e.g., Stephen Hawkings). Imran Zakir

45. Auditory Output Methods Device Speech output concatenation Speech output: text- to-speech synthesis Description Digital playback of concatenated speech utterances. Conversion of text to speech with synthetic playback. Key Features/Remarks Fragments of speech are digitally recorded and then re-assembled and played back to produce the desired words and sentences. Limited value, tedious, discontinuities are often difficult to mask. Examples: speaking clock,numbers in bank transactions via phone, routing of messages. Synthesis of words and sentences is controlled by rules of phonemics and rules that relate to the context of a sentence or phrase. Used in conjunction with a database. Pitch and tone can be varied, but the speech produced can sound unnatural, synthetic, tinny, and mechanical. Improving (e.g., stock quotation system). Imran Zakir