Jeddie BereHCI Assignment 1Describe any 4 interaction devices in detail and explain the developments that occurredon these devices over the years. What does the future hold for them? 1. A keyboard- Is a typewriter-style keyboard which uses an arrangement of buttons or keys to act as mechanical levers or electronic switches. Following the decline of punch cards and paper type, interaction via tele-printer style became the main input device for computers. Despite the developments of alternative input devices such as the mouse, touch screen pen, character recognition and voice recognition. The keyboard remains the most commonly used and most versatile device used for direct human input into computers. There are 2 types of keyboards namely, a) MECHANICAL KEYSWITCH KEYBOARDS This type uses an individual switch for each key. Pressing a key creates a connection between 2 signal lines from the keyboard controller. When a connection is made the keyboard controller sends a signal to the computer with information about the type of key selected. b)CAPACITATIVE A keyboard will have 2 sheets of semi-conductive material separated by a thin sheet of Mylar .When a key is pressed the plunger presses the 2 sheets of semi-conductive material together , changing the total capacitance of the 2 sheets. The keyboard controller can tell the key selected by the amount of capacitance. A keyboard typically has characters engraved or printed on the keys and each press of keys typically corresponds to a single written symbol. Most keyboard keys produce letters, numbers or signs, other keys or simultaneous key presses can produce actions or computer commands. In normal usage a keyboard is used to type text and number into word processor, text editor or other programs. In a modern computer, the interpretation of key presses is generally the left to the right software. Keyboards are the only way to enter commands on a commandlineinterface. The history of the keyboard –while typewriters are the definite ancestor of all key-based text entry devices, the computer keyboard as a device for electromechanical data entry and communication derives largely from the utility of two devices, tele-printers and keypunches. It was through such devices that the modern computer keyboard inherited their layouts. In 1870s the keyboard on the tele-printer played a strong role in point to point and point to multipoint communication while the keyboard on the keypunch device played a strong role in data entry and storage. The keyboard remained primarily, most integrated computer peripheral well into personal computing until the introduction of a mouse as a consumer device in 1984. By this time text exclusive user interfaces with sparse graphics gave way to comparatively graphics rich icons on screen. However the keyboard remain control to human computer interaction to the
present , as even mobile personal computing devices such as smart phones and tablets adapt the keyboard as an optional virtual touch screen based means of data entry. Spectacular improvements have been developed for this device, a standard requirement for all PCs, since it has first appeared.With all kind of embedded functions, but essentially nothing has changed, at least up until now. However, things might take a different turn, with the extraordinary wireless keyboardconceptdevelopedbythecompanyOptimus.2. Monitor or display-is an electronic visual display for computers. Monitor comprises the display device circuitry and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display, while older monitors use a cathode ray tube about as deep as the size screen size. Originally, computer monitors were used for data processing while television receivers were used for entertainment. From 1980 onwards, computers and their monitors have been used for both data processing and entertainment while television has implemented some computer functionality. The history of monitors- the first monitors used was cathode ray tubes. Until early 1980s, they were known as video display terminal and were physically attached to the computer and keyboard. The monitors were monochrome, flickered and the image quality was poor. 1981 IBM introduced the Colour Graphic Adapter which could display four colours. In 1984 Enhanced Graphics Adapter was introduced which was capable of producing 16million colours and had a resolution of 640 by 350. CRT remained the standard for computer monitors through the 1990s. CRT technology remained dominant in the personal computer monitor market into the new millennium partly because it was cheaper to produce and offered viewing angles close to 180 degrees. The future vision is to create light weight, portable display surfaces that can be instantly updated and are used for everything from videos to foldable computer screens to wall paper. A research on paper-like displays focuses on investigating new materials and manufacturing costs.3. The mouse –is a pointing device that functions by detecting two dimensional motions relative to its supporting surface. Physically, a mouse consists of an object held under one of the user’s hands, with one or more buttons. The mouse sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features that can add more control or dimensional input. The mouses motion typically translates into the motion of a pointer on a display, which allows for fine control of a graphical user interface Computer mice began to appear in the early 1980s but many computers require an additional expansion board or card to use them during this period of history. Many mice were beige or white. In late 1980s a greater variety of IBM compatible computers began to be sold with a serial port built in and Apple Macintosh system were among the first to be sold with a mouse included. Most mice had either one or two buttons. Software was generally designed so that it could be used with or without a pointing device. A disadvantage
of serial computer mouse is that they must be plugged when other serial accessories are utilised on computers which have only one port of this type. In early 1990s one mice button had become relatively cheap. Microsoft offered a bundled mouse and windows 3.1 package, because of the significant advantage it provides in using windows. Mice with scroll wheels or USB cables have become more wide spread. A greater number of computers now have dark coloured exteriors and mice with similar coloration have been provided to match them. In 1999, Apple dropped the use of ADB mouse ports and replaced them with USB. Overally, the history of the computer mice has frequently involved different ports, more buttons and a trend in favour of including them with new systems. It remains to be seen whether the mouse will continue to undergo such changes during the next ten years or twenty years or if it will stay much the same. Mice might become obsolete, at least as far as the mainstream segment is concerned. The main reason for this situation is the appearance and rapid developments of touch screen technology and touch pads, which enable users to carry out the same functions as the ones previously enabled by the mice.4. Light pen – a light pen is an input device that is used with a cathode ray tube display to point at items on the screen or to draw new items or modify existing ones. The light pen had a photo sensor at the tip that responds to the peak illumination that occurs when the CRT scanning spot passes its point of focus. The display system correlated the timing of the pulse from the photo sensor with the item being displayed to determine the position of the light pen. A light pen can work with any CRT based display but not with LCD display. The light pen is used to draw items with the aid of a tracking cross. As the light pen is moved across the screen, the part of the tracking cross sensed changes thus allowing the direction of movement of the light pen to be ascertained. The tracking cross can be redrawn to locate it at the expected new centre of the light pen’s position and thus appears to follow the light pen. The user brings the pen button to make contact. The light pen is fairly easy to implement. The light pen works by sensing the sudden small change in brightness of a point on the screen when the electron gun refreshes that spot. By noting exactly where the scanning has reached at that moment, the X, Y position of the pen can be resolved. This is usually achieved by the light pen causing an interrupt, at which point the scan position can be read from a special register or computed from a counter or timer. The pen position is updated on every refresh of the screen. The history of the light pen- light pen became moderately popular during the early 1980s. It was notable for its use in the Fair light Computer Music Instrument (CMI) was the first polyphonic digital sampling synthesiser. It was designed in 1979 by the founders of Fairlight,
Peter Vogel and Kim Ryrie and based on a dual microprocessor computer designed by tonyFurse in Sydney, Australia.The first light pen was created around 1952 as part of theWhirlwind Project.While most people do majority of their writing on computers these days, there is still a hugemarket for pens especially innovative ones. These creative innovations go a way beyond thecolourful pen or sparkly gel writers. There is a whole new genre of digital pens, for example,that look like they will play significant roles in future. They allow people to write on anysurface, eliminating the need to destroy as the pen records motions digitally storing themfor future uploads on computers.