Input Devices

History of computing:

Originally, the term "computer" referred to a person who performed numerical calculations, often with the aid of a mechanical calculating device. Examples of these early calculating devices, the first ancestors of the computer, included the abacus and the Antikythera mechanism, an ancient Greek device for calculating the movements of planets, dating from about 87 BC.[1] The end of the Middle Ages saw a reinvigoration of European mathematics and engineering, and Wilhelm Schickard's 1623 device was the first of a number of European engineers to construct a mechanical calculator.[2] The abacus has been noted as being an early computer, as it was like a calculator in the past. In 1801, Joseph Marie Jacquard made an improvement to existing loom designs that used a series of punched paper cards as a program to weave intricate patterns. The resulting Jacquard loom is not considered a true computer but it was an important step in the development of modern digital computers. Charles Babbage was the first to conceptualize and design a fully programmable computer as early as 1820, but due to a combination of the limits of the technology of the time, limited finance, and an inability to resist tinkering with his design, the device was never actually constructed in his lifetime. A number of technologies that would later prove useful in computing, such as the punch card and the vacuum tube had appeared by the end of the 19th century, and large-scale automated data processing using punch cards was performed by tabulating machines designed by Hermann Hollerith.

During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated, special-purpose analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. These became increasingly rare after the development of the programmable digital computer.

A succession of steadily more powerful and flexible computing devices were constructed in the 1930s and 1940s, gradually adding the key features of modern computers, such as the use of digital electronics (largely invented by Claude Shannon in 1937)[3] and more flexible programmability. Defining one point along this road as "the first digital electronic computer" is exceedingly difficult. Notable achievements include the Atanasoff-Berry Computer (1937), a special-purpose machine that used valve-driven (vacuum tube) computation, binary numbers, and regenerative memory; the secret British Colossus computer (1944), which had limited programmability but demonstrated that a device using thousands of valves could be made reliable and reprogrammed electronically; the Harvard Mark I, a large-scale electromechanical computer with limited programmability (1944); the decimal-based American ENIAC (1946) — which was the first general purpose electronic computer, but originally had an inflexible architecture that meant reprogramming it essentially required it to be rewired; and Konrad Zuse's Z machines, with the electromechanical Z3 (1941) being the first working machine featuring automatic binary arithmetic and feasible programmability.

The team who developed ENIAC, recognizing its flaws, came up with a far more flexible and elegant design, which has become known as the Von Neumann architecture (or "stored program architecture"). This stored program architecture became the basis for virtually all modern computers. A number of projects to develop computers based on the stored program architecture commenced in the mid to late-1940s; the first of these were completed in Britain. The first to be up and running was the Small-Scale Experimental Machine, but the EDSAC was perhaps the first practical version that was developed.

The Apple II, an early personal computer

Valve (tube) driven computer designs were in use throughout the 1950s, but were eventually replaced with transistor-based computers, which were smaller, faster, cheaper, and much more reliable, thus allowing them to be commercially produced, in the 1960s. By the 1970s, the adoption of integrated circuit technology had enabled computers to be produced at a low enough cost to allow individuals to own a personal computer of the type familiar today.

Input Devices

1. Webcam:

A web camera (or webcam) is a real-time camera whose images can be accessed using the World Wide Web, instant messaging, or a PC video calling application.

Web-accessible cameras typically involve a digital camera which uploads images to a web server, either continuously or at regular intervals. This may be achieved by a camera attached to a PC, or by dedicated hardware. Videoconferencing cameras typically take the form of a small camera connected directly to a PC.

History:

Started in 1991, the first webcam was pointed at the Trojan room coffee pot in the computer science department of Cambridge University. This webcam is now defunct, as it was finally switched off on 22 August 2001. The final image captured by the camera can still be viewed at the webcam's homepage [1].

As with many new technologies, webcams and webcam chat found early commercial adoption and aggressive technology advancement through use by the pornography industry. The adult industry required 'live' images and requested a Dutch developer to write a piece of software that could do this without using so called 'plugins'. This led to the birth of the 'live streaming webcam', which is still available in various forms today.

Videoconferencing:

As webcam capabilities have been added to instant messaging text chat services such as Yahoo Messenger, AOL Instant Messenger (AIM), MSN Messenger and Skype, one-to-one live video communication over the internet has now reached millions of mainstream PC users worldwide. Increased video quality has helped webcams encroach on traditional video conferencing systems. New features such as lighting, real-time enhancements (retouching, wrinkle smoothing and vertical stretch) can make users more comfortable, further increasing popularity.

Many companies have tried to jump on the 'live video' bandwagon, most notably 'vdolive' (an Israeli company), Spotlife (a Logitech daughter company) and many others; most of these have since failed.

2.Digital paper:

Digital paper is patterned paper used in conjunction with a digital pen to create handwritten digital documents. The proprietary printed dot pattern uniquely identifies the position coordinates on the paper. The digital pen uses this pattern to store the handwriting and upload it to a computer.

The pattern

Digital paper uses a proprietary pattern, a kind of 2-D barcode, the most common of which is the Anoto pattern. Each dot is spaced about 0.3mm apart. The full Anoto pattern consists of 669,845,157,115,773,458,169 dots. The full Anoto pattern encompasses an area exceeding 4.6 million km^2. This corresponds to 73 trillion letter-size papers.

The paper

The paper pattern space is divided into various domains. These domains can pre-define paper types or may be used to indicate paper purpose such as memo formatting, personal planners, notebook paper, Post-it notes or forms of any sort.

Printing

The Anoto pattern can be printed onto almost any paper with a printing process of 600 dpi resolution or better. The paper may be any shape or size greater than 2x2 mm. Standard printing techniques with standard carbon-based printing ink is used. The carbon-based ink will absorbe the pen's infrared light that makes the pattern visible to the Digital Pen. Other colors of ink, including noncarbon-based black, can be used to print information visible to the user, but not visible to the digital pen.

Digital paper should not be confused with electronic paper.

3. D-Pad:

A D-pad (short for directional pad) is a plus sign–shaped control found on nearly all modern video game console gamepads and game controllers, with one button on each point. Like early video game joysticks, the vast majority of D-pads are digital; in other words, only the directions provided on the D-pad buttons can be used, with no intermediate values. However, combinations of two directions (up and left, for example) do provide diagonals. The D-pad first came to prominence on the controller for the Famicom.

Although digital D-pads offer less nuance and flexibility than analog sticks, they can easily be manipulated (requiring little movement of the thumb) with very high accuracy. In recent years, D-pads have been developed which can measure different levels of pressure, giving a degree of analog control.

History

A precursor to the standard D-pad was used by the Intellivision console, which was released by Mattel Electronics in 1980. The Intellivision's unique controller featured the first alternative to a joystick on a home console, a circular pad that allowed for 16 directions of movement by pressing it with the thumb. A precursor to the D-pad also appeared on Entex's short lived "Select A Game" cartridge based handheld system; it featured non-connected raised left, right, up and down buttons aligned to the left of a row of action buttons.

The first "connected" (pad) style D-pad appeared appropriately enough in 1981 on a handheld game system- "Cosmic Hunter" on Milton Bradley's Microvision. The pad was operated the same way today's dpads do, using the thumb to manipulate the onscreen "hero" character in any of four directions.

In 1982, Nintendo's Gunpei Yokoi updated this idea, shrinking it and altering the points into the familiar modern "cross" design for their Donkey Kong handheld game. The design proved to be popular for subsequent Game & Watch titles, although the previously introduced non-connected D-pad style was still utilized on various later Game & Watch titles, including the Super Mario Brothers handheld game. This particular design was patented.

Initially intended to be a compact controller for the Game & Watch handheld games alongside the prior nonconnected style pad, Nintendo realized that Gunpei's updated design would also be appropriate for regular consoles, and Nintendo made the D-pad the standard directional control for the hugely successful Famicom/Nintendo Entertainment System. All major video game consoles since have had a D-pad on their controllers. Arcade games, however, have largely continued using joysticks.

A recent trend in modern consoles, beginning with the Nintendo 64, has been to provide both a D-pad and a compact thumb-operated analog stick; depending on the game, one type of control may be more appropriate than the other.

4. 3D scanner

A 3D scanner is a device that analyzes a real-world object or environment to collect data on its shape and possibly color. The collected data can then be used to construct digital, three dimensional models that are used in a wide variety of applications. These devices are used extensively by industry in the production of such things as movies and video games. Other applications include industrial design and prototyping, computer vision and documentation of cultural artifacts.

Functionality

The purpose of a 3D scanner is usually to create a point cloud of geometric samples on the surface of the subject. These points can then be used to extrapolate the shape of the subject (a process called reconstruction). If color information is collected at each point, then the colors on the surface of the subject can also be determined.

3D scanners are very analogous to cameras. Like cameras, they have a cone-like field of view, and like cameras, they can only collect information about surfaces that are not obscured. While a camera collects color information about surfaces within its field of view, 3D scanners collect distance information about surfaces within its field of view. The “picture” produced by a 3D scanner describes the distance to a surface at each point in the picture. If a spherical coordinate system is defined in which the scanner is the origin and the vector out from the front of the scanner is f=0 and ?=0, then each point in the picture is associated with a f and ?. Together with distance, which corresponds to the r component, these spherical coordinates fully describe the three dimensional position of each point in the picture, in a local coordinate system relative to the scanner.

For most situations, a single scan will not produce a complete model of the subject. Multiple scans, even hundereds, from many different directions are usually required to obtain information about all sides of the subject. These scans have to be brought in a common reference system, a process that is usually called aligment or registration, and then merged to create a complete model. This whole process, going from the single range map to the whole model, is usually known as the 3d scanning pipeline[1].

The pistol-shaped gun has two expansion slots that are compatible with the VMU and the vibration pack. This allows the player(s) to save their games and get a more authentic arcade-like experience. The gun has been acclaimed by users as being extremely accurate.

5. Light pen

A light pen is a computer input device in the form of a light-sensitive wand used in conjunction with the computer's CRT monitor. It allows the user to point to displayed objects, or draw on the screen, in a similar way to a touch screen but with greater positional accuracy. A light pen can work with any CRT-based monitor, but not with LCD screens, projectors or other display devices.

A light pen is fairly simple 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 resolves the X,Y position of the pen. This is usually achieved by making the light pen cause an interrupt, at which point the scan position can be read off from a special register, or computed from a counter or timer. The pen position is updated on every refresh of the screen.

The light pen became moderately popular during the early 1980s. It was notable for its use in the Fairlight CMI, and the BBC Micro. However, due to the fact that the user was required to hold his or her arm in front of the screen for long periods of time, the light pen fell out of use as a general purpose input device.

The first light pen was used around 1957 on the Lincoln TX-0 computer at the MIT Lincoln Laboratory. Contestants on the game show Jeopardy! use a light pen to write down their wagers and answers for the Final Jeopardy! round. Light pens are used country-wide in Belgium for voting.

6. Light Gun

The NES Zapper, Nintendo´s light gun and regarded as the quintessential device of this nature. Shown is the grey version, which would later be replaced by an orange edition due to striking similarities with real arms.

A light gun is a pointing device for computers and a control device for arcade and video games. The first light guns appeared in the 1930s, following the development of light-sensing vacuum tubes. It wasn't long before the technology began appearing in arcade shooting games, beginning with the Seeburg Ray-O-Lite in 1936. These early light gun games used small targets (usually moving) onto which a light-sensing tube was mounted; the player used a gun (usually a rifle) that emitted a beam of light when the trigger was pulled. If the beam struck the target, a "hit" was scored. Modern screen-based light guns work on the opposite principle -- the sensor is built into the gun itself, and the on-screen target(s) emit light rather than the gun. The first light gun of this type was used on the MIT Whirlwind computer.

The light gun, and its descendant, the light pen, are now rarely used as computer pointing devices, because of the popularity of the mouse and changes in monitor display technology -- light guns can only work with standard CRT monitors.

7. Touchpad

A touchpad is an input device commonly used in laptop computers. They are used to move the cursor, using motions of the user's finger. They are a substitute for a computer mouse. Touchpads vary in size but are rarely made larger than 50 cm² (8 in²). They can also be found in PDA's.

Touchpads commonly operate by sensing the capacitance of a finger, or the capacitance between sensors. Capacitive sensors are laid out along the horizontal and vertical axis of the touchpad. The location of the finger is determined from the pattern of capacitance from these sensors. This is why they will not sense the tip of a pencil or even a finger in a glove. Moist and/or sweaty fingers can be problematic for those touchpads that rely on measuring the capacitance between the sensors.

Touchpads are relative motion devices. That is, there is no isomorphism from the screen to the touchpad. Instead, relative motion of the user's fingers causes relative motion of the cursor. The buttons below or above the pad serve as standard mouse buttons. Depending on the model of touchpad and drivers behind it, you may also click by tapping your finger on the touchpad, and drag with a tap following by a continuous pointing motion.

8.Trackball

A trackball is a pointing device consisting of a ball housed in a socket containing sensors to detect rotation of the ball about two axes—like an upside-down mouse, but with the ball sticking out more. The user rolls the ball with their thumb, fingers, or the palm of their hand to move a cursor. Tracker balls are common on CAD workstations for ease of use and, before the advent of the touchpad, on portable computers, where there may be no desk space on which to use a mouse. Some clip onto the side of the keyboard and have integral buttons which have the same function as mouse buttons.

Trackballs are sometimes seen on computerised special-purpose workstations, such as the radar consoles in an air-traffic control room or sonar equipment on a ship or submarine. Modern installations of such equipment may use mice instead, since most people now already know how to use one. However, military mobile anti-aircraft radars and submarine sonars tend to continue using trackballs, since they can be made much more durable and are better fit for fast emergency use.

2. Output Devices:

1. Focus-plus-context screen:

The original focus-plus-context screen prototype consisted of an 18" LCD screen embedded in a 5' front-projected screen. The callout shows the different resolutions of focus and context area.

A focus-plus-context screen is a specialized type of display device that consists of one or more high-resolution "focus" displays embedded into a larger low-resolution "context" display. Image content is displayed across all display regions, such that the scaling of the image is preserved, while its resolution varies across the display regions.

The original focus-plus-context screen prototype consisted of an 18"/45cm LCD screen embedded in a 5'/150cm front-projected screen. Alternative designs have been proposed that achieve the mixed-resolution effect by combining two or more projectors with different focal lengths Escritoire.

While the high-reolution area of the original prototype was located at a fixed location, follow-up projects have obtained a movable focus area by using a Tablet.

2. Computer printer

A computer printer, or more commonly just a printer, is a device that produces hard copy (permanent human-readable text and/or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies). Many printers are primarily used as computer peripherals, and are permanently attached to a computer which serves as a document source. Other printers, commonly known as network printer, have built-in network interfaces (typically wireless or Ethernet), and can serve as a hardcopy device for any user on the network. In addition, many modern printers can directly interface to electronic media such as memory sticks or memory cards, or to image capture devices such as digital cameras, scanners; some printers are combined with a scanners and/or fax machines in a single unit. A printer which is combined with a scanner can essentially function as a photocopier.

Printers are designed for low-volume, short-turnaround print jobs; requiring virtually no setup time to achieve a hard copy of a given document. However, printers are generally slow devices (10 pages per minute is considered fast; and many consumer printers are far slower than that), and the cost-per-page is relatively high, In contrast, the printing press (which serves much the same function), is designed and optimized for high-volume print jobs such as newspaper print runs--printing presses are capable of hundreds of pages per minute or more, and have an incremental cost-per-page which is a fraction of that of printers. The printing press remains the machine of choice for high-volume, professional publishing. However, as printers have improved in quality and performance, many jobs which used to be done by professional print shops are now done by users on local printers; see desktop publishing.

3. RepRap

The RepRap Project is an active undertaking that seeks to create self replicating robots. It is attempting to prove the following hypothesis:

Rapid prototyping and direct writing technologies are sufficiently versatile to allow them to be used to make a von Neumann Universal Constructor.

A Universal Constructor, or Clanking replicator, is a machine which uses self-replication to create new generations of itself. It is speculated that the RepRap will eventually demonstrate evolution in this process as well as being able to increase in number exponentially.

As RepRap is a self-replicating rapid prototyping machine, from a practical point of view this means it will be possible to cheaply distribute new rapid prototypers to people and communities giving them the capability to easily create products and artifacts for themselves (or download designs from the internet) without the need for large and expensive industrial infrastructure. RepRap has the potential to be a disruptive technology.

4. Monitor

A computer display, monitor or screen is a computer peripheral device capable of showing characters and/or still or moving images generated by a computer and processed by a graphics card. Monitors generally conform to one or more display standards. Sometimes the name "display" suits better than the word "monitor", as the latter term can also ambiguously refer to a "machine-level debugger" or to a "thread synchronization mechanism". Some people also refer to computer displays as "heads", especially when talking about multiple displays connected to a single physical computer. Once an essential component of a computer terminal, computer displays have long since become standardized peripherals in their own right.

5. Video projector

A video projector takes a video signal and projects the corresponding image on a projection screen using a lens system. All video projectors use a very bright light to project the image, and most modern ones can correct any curves, blurriness, and other inconsistencies through manual settings. Video projectors are widely used for conference room presentations, classroom training, and home theatre applications.

Video projectors may also be built into cabinets which use a rear projection screen to form a single unified display device, now popular for "home theater" applications.

Common display resolutions for a portable projector include SVGA (800x600 pixels), XGA (1024x768 pixels), and 720p (1280x720 pixels).

The cost of a device is not only determined by its resolution, but also by its brightness. While most modern projectors will provide sufficient brightness at night or under controlled lighting such as in a basement with no windows[38], a projector with a higher lumens rating is required for a room with a higher amount of ambient light. A rating of 1000 to 1500 ANSI lumens or lower is suitable for smaller rooms with controlled lighting or low ambient light.[38][39] Between 1500 to 3000 ANSI is suitable for medium sized rooms with some ambient light or dimmed light. Over 3000 ANSI is appropriate for very large screens in a large room with no lighting control (for example, a conference room). Projected image size is also important, as the total amount of light does not change, as size increases, brightness decreases. An increase in a widescreen image from 80 inches diagonal to 100 inches diagonal reduces the image brightness by 35 percent.

6.Speakers

Speakers are the amazing devices that are used to play all sorts of music and sounds from your computer! They take the electric signals stored CDs and Sound is produced when an object vibrates through the air. When the object vibrates, it disturbs the air particles around it, which in turn disturb the air particles around them, which in turn disturb the air particles around them, etc. All of these air particles carry the pulse of the vibrating object through the air. These moving particles create different levels of pressure throughout the atmosphere. Thus, a vibrating object sends a wave of pressure fluctuations that eventually reach your ear, where your brain converts it to a series of different sounds.

When you want to listen to certain music, your sound card will retrieve it from your computer's hard disk, where it is stored as electric signals. Your speakers will take these signals and convert them to sound waves, which will travel to your eardrums.