A scroll wheel is a hard plastic or rubbery disc on a computer mouse, perpendicular to the mouse surface. It is located between the left and right mouse buttons, it is used, for scrolling. It can also be used as a third mouse button by pressing on it; the wheel is – but not always – engineered with detents to turn in discrete steps, rather than continuously as an analog axis, to allow the operator to more intuit how far they are scrolling. Some modern mice can scroll horizontally as well as vertically, using a tilting scroll-wheel, scroll ball, pointing stick, optical sensor, or a second scroll wheel. Logitech mice with'Free Spinning' scroll wheels use a 14 gram scroll wheel with high rotational inertia like a flywheel that can be used to scroll through long pages and lists. A peculiar early example was a mouse by Saitek. Scroll wheels are prevalent on modern computer mice and have become an integral part of the hardware interface. However, non-wheeled mice are still available. Scroll wheels can be found on such handheld devices such as PDAs, portable digital audio players such as the original Apple iPod, or mobiles phones such as early Sony models and BlackBerry devices.
The scroll wheel on a mouse has been invented multiple times by different people unaware of the others' work. Other scrolling controls on a mouse, the use of a wheel for scrolling both precede the combination of wheel and mouse; the earliest known example of the former is the Mighty Mouse prototype developed jointly by NTT, Japan and ETH Zürich, Switzerland in 1985. It had a thumb-operated combined analog button/toggle switch on the side for smooth scrolling. At the ACM SIGCHI conference in 1989, Gina Danielle Venolia from Apple presented a mouse prototype with a horizontal thumb-wheel for scrolling and for moving along the Z-axis. In her patent application from 1992 were wheels were on vertical wheels. Jack McCauley claims to having developed an early mouse prototype with a top-mounted wheel for the Z-axis, at about the same time. In 1995, the Taiwanese company KYE Systems released the first commercial mouse with scroll wheel, it was named Genius EasyScroll and was available as Mouse Systems ProAgio.
The scroll wheel was popularized by the Microsoft IntelliMouse in 1996 along with support for the mouse wheel in Microsoft Office 97. It had been based on ideas developed by Eric Michelman since 1993 with input from Chris Graham. In the 21st century, scroll wheels patterned after the mouse's started appearing on keyboards as well on Logitech and Microsoft models, it was located to the left of the caps lock key. The implementation of scroll wheels on laptop computers has faded, while touchpads are programmed with a pointing device gesture to substitute for them. In many applications, holding down the control key while rolling the scroll wheel causes the text size to increase or decrease, or an image in an image-editing or map-viewing program to zoom in or out, if such a feature is available. Clicking the link with a scroll wheel button makes the link open in a new tab, clicking on the opened tab closes it. In first-person shooter games, the scroll wheel is set to change weapons; because of this some gaming mice, such as Logitech G500, implement a locking feature that lets the mouse switch between scrolling in steps and continuous scrolling.
The scroll wheel is sometimes used to control the zoom of scoped weapons and binoculars. FPS games with an emphasis on realism may choose to use the wheel for changing between stances or adjusting the range settings on iron sights. Since the introduction of tilting scroll-wheels, many FPS games use the left-right motion of the scroll wheel to cause the player to lean left and right. A less common use is to use the mouse wheel to adjust the player's speed of movement. Real time strategy games use the mouse wheel to change the altitude of the camera. CAD applications such as AutoDesk's AutoCAD use the mouse wheel to navigate the space in which the user is drawing; this has become a de facto standard in 3D applications such as Trimble's SketchUp where the wheelscroll is zoom, wheelclick with a mouse drag is orbit. Scroll lock
Synaptics is a publicly owned San Jose, California-based developer of human interface hardware and software, including touchpads for computer laptops. Synaptics sells its products to original equipment manufacturers and display manufacturers. Since its founding in 1986, the company's notable innovations include the first computer touchpad, touch technology for the click wheel on the classic iPod, touch sensors used in numerous Android phones and display driver integrated chips, biometrics technology for fingerprint sensors. All touch and fingerprint technology was based on capacitive sensing up until the introduction of optical fingerprint sensing in late 2016. Scientists and engineers Federico Faggin and Carver Mead founded Synaptics in 1986, inspired by their interest in neural networks and how technology might imitate neural networks. Faggin and Mead applied their research and discoveries on neural networks and transistors on chips to build pattern recognition products; the name of the company is blending synapse and electronics.
In 1991, Synaptics patented a refined "winner take all" circuit for teaching neural networks how to recognize patterns and images, so called because it uses basic physics principles in order to select the strongest signal from the array of different processors. During Synaptics' early years, the laptop industry was struggling to make devices thinner because the spherical trackballs included in them required thicker device builds. Synaptics' founders recognized this issue and in 1992, used the pattern recognition techniques it developed to build the world's first touchpad. By 1994, Twinhead and Epson America had adopted Synaptics' touchpad for their computers, followed by Apple in 1995 and by other leading computer manufacturers of the time, including Compaq and Dell; as adoption of the touchpad grew, Synaptics sought to integrate the technology with other products and expand the company with a range of human interface technologies. In 1999, Francis Lee took over as CEO; the company had an initial public offering in 2002.
In 2004, Apple debuted the iPod Mini and fourth-generation iPod, both featuring a scrolling click wheel enabled by Synaptics' capacitive touch technology, Synaptics provided a similar, vertical solution for the click wheel of the Creative Zen Touch portable media player. In 2005, Synaptics sensors were featured in the Samsung B310, the first mobile phone to use capacitive-touch technology – and as early 2017, Samsung and many other Android phone manufacturers continued to use Synaptics sensors in their phones. In October 2006, Synaptics provided a live demonstration of the Onyx, a concept smartphone with a color touchscreen enabled by its ClearPad touch controller technology; the Onyx's touch sensor could tell the difference between a finger and a cheek, preventing accidental inputs during calls. In 2007, LG launched its Prada phone, the world's first mobile phone with a capacitive touchscreen, featuring Synaptics' touch sensors. Synaptics' touchscreen technology was featured in Logitech's Harmony line of universal remote controls with capacitive-touch capabilities, which debuted in 2008.
In 2009, Synaptics revealed the Fuse concept smartphone, which included several features that are now standard in modern smartphones, showcased it at the Consumer Electronics Show in January 2010. The Fuse offered touch sensitivity on the back of the phone, the ability to interact with the phone by squeezing, animated icons, a user interface sensitive to the phone's orientation and tilt, haptic gestures. In 2011, the company appointed Rick Bergman to succeed Francis Lee as CEO. In 2012, Synaptics introduced the first full-function capacitive-touch product that used pressure recognition to allow for multi-finger and variable-force input. In late 2013, Synaptics acquired Validity Sensors, a fingerprint sensor vendor, adding capacitive fingerprint sensing to Synaptics' portfolio. Synaptics acquired Renesas SP Drivers Inc. a Japanese company specializing in chips that manage LCD displays, in 2014. The acquisition enabled Synaptics to integrate offerings of touch and display driver technologies into a single "TDDI" chip.
With its growing portfolio of touch and fingerprint offerings, in 2015 the company expanded into additional markets, including automotive, wearables and PC peripherals. In July 2015, Synaptics debuted a unique “match-in-sensor” fingerprint authenticator for laptops and other devices that authenticates the fingerprint within the chip itself for greater security; the company debuted the Clear ID FS9100, its first optical-based fingerprint sensor, in December 2016, after improving the technology, sent it into full production a year later. In January 2018, the Chinese company Vivo announced the X20 Plus UD, a smartphone featuring Synaptics’ Clear ID optical fingerprint sensor; this was the world’s first full-production smartphone with fingerprint authentication directly in the OLED display. In July 2017, Synaptics acquired Conexant Systems, an Amazon Alexa partner that creates voice and audio software and silicon products for smart homes, for $300 million in cash and 726,666 shares of stock. At the same time, Synaptics acquired Marvell Technology Group's Multimedia Solutions unit, which creates video and audio processing technology, for $95 million.
The two acquisitions were intended to aid Synaptics' expansion into the Internet of things market. As of July 2017, Synaptics held more than 1,900 granted or pending patents for human interface technologies. Many Synaptics
Olivetti S.p. A. is an Italian manufacturer of typewriters, tablets, smartphones and other such business products as calculators and fax machines. Headquartered in Ivrea, in the Metropolitan City of Turin, the company has been part of the Telecom Italia Group since 2003; the first commercial programmable "desktop computer", the Programma 101, was produced by Olivetti in 1964 and was a commercial success. The company was founded as a typewriter manufacturer by Camillo Olivetti in 1908 in Italy; the firm was developed by his son Adriano Olivetti. Olivetti opened its first overseas manufacturing plant in 1930, its Divisumma electric calculator was launched in 1948. Olivetti produced Italy's first electronic computer, the transistorised Elea 9003, in 1959, purchased the Underwood Typewriter Company that year. In 1964 the company sold its electronics division to the American company General Electric, it continued to develop new computing products on its own. In the 1970s and 1980s they were the biggest manufacturer for office machines in Europe and 2nd biggest PC vendor behind IBM in Europe.
In 1980, Olivetti began distributing in Indonesia through Dragon Communication. In 1981, Olivetti installed the electronic voting systems for the European Parliament in Strasburg and Luxembourg. In September 1994, the company launched. From 2003 is part of the TIM Group. Olivetti was famous for the attention it gave to design: preoccupation with design developed into a comprehensive corporate philosophy, which embraced everything from the shape of a space bar to the color scheme for an advertising poster. In 1952, the Museum of Modern Art held an exhibit titled "Olivetti: Design in Industry". Another major show, mounted by the Musée des Arts Décoratifs in Paris in 1969, toured five other cities. Olivetti was renowned for the caliber of the architects it engaged to design its factories and offices, including Le Corbusier, Louis Kahn, Gae Aulenti, Egon Eiermann, Figini-Pollini, Ignazio Gardella, Carlo Scarpa, BBPR, many others. From the 1940s to the 1960s, Olivetti industrial design was led by Marcello Nizzoli, responsible for the Lexicon 80 and the portable Lettera 22.
Mario Bellini and Ettore Sottsass directed design. Bellini designed the Programma 101, Divisumma 18 and Logos 68 calculators and the TCV-250 video display terminal, among others. Sottsass designed the Tekne 3 typewriter, Elea 9003 computer, the Praxis 48 typewriter, the Valentine portable typewriter, others. Michele De Lucchi designed the Gioconda calculator. During the 1970s Olivetti sold two ranges of minicomputers. The'A' series started with the typewriter-sized A4 through to the large A8, the desk-sized DE500 and DE700 series. George Sowden worked for Olivetti from 1970 until 1990, designed their first desktop computer, Olivetti L1, in 1978. In 1991, Sowden won the prestigious ADI Compasso d'Oro Award for the design of the Olivetti fax OFX420. Olivetti paid attention to more than the importance of product design. Giovanni Pintori was hired by Adriano Olivetti in 1936 to work in the publicity department. Pintori was the creator of the Olivetti logo and many promotional posters used to advertise the company and its products.
During his activity as Art Director from 1950, Olivetti's graphic design obtained several international awards, he designed works that created the Olivetti image and became emblematic Italian reference in the history of 20th-century design. Those designers created the Olivetti Synthesis office furniture series which were used to be installed in Olivetti's own headquarters, worldwide branch offices and show rooms. Olivetti produced some industrial production machinery, including metal working machines of the Horizon series. Olivetti began with mechanical typewriters when the company was founded in 1909, produced them until the mid 1990s; until the mid 1960s they were mechanical, models such as the portable Olivetti Valentine were designed by Ettore Sottsass. With the Tekne/Editor series and Praxis 48, some of the first electromechanical typewriters were introduced; the Editor series was used for speed typing championship competition. The Editor 5 from 1969 was the top model of that series, with proportional spacing and the ability to support justified text borders.
In 1972 the electromechanical typeball machines of the Lexicon 90 to 94C series were introduced, as competitors to the IBM Selectric typewriters, the top model 94c supported proportional spacing and justified text borders like the Editor 5, as well as lift-off correction. In 1978 Olivetti was one of the first manufacturers to introduce electronic daisywheel printer-based word processing machines called TES 401 and TES 501; the ET series typewriters without LCD and different levels of text editing capabilities were popular in offices. Models in that line were ET 121, ET 201, ET 221, ET 225, ET 231, ET 351, ET 109, ET 110, ET 111, ET 112, ET 115, ET 116, ET 2000, ET 2100, ET 2200, ET 2250, ET 2300, Et 2400 and ET 2500. For home users in 1982 the Praxis 35, Praxis 40 and 45D were some of the first portable electronic typewriters. Olivetti added the Praxis 20, ET Compact 50, ET Compact 60, ET Compact 70, ET Compact 65/66, the ET Personal series and Linea 101; the top models were 8 lines LCD based portables like Top 100 and Studio 8
Apple Inc. is an American multinational technology company headquartered in Cupertino, that designs and sells consumer electronics, computer software, online services. It is considered one of the Big Four of technology along with Amazon and Facebook; the company's hardware products include the iPhone smartphone, the iPad tablet computer, the Mac personal computer, the iPod portable media player, the Apple Watch smartwatch, the Apple TV digital media player, the HomePod smart speaker. Apple's software includes the macOS and iOS operating systems, the iTunes media player, the Safari web browser, the iLife and iWork creativity and productivity suites, as well as professional applications like Final Cut Pro, Logic Pro, Xcode, its online services include the iTunes Store, the iOS App Store, Mac App Store, Apple Music, Apple TV+, iMessage, iCloud. Other services include Apple Store, Genius Bar, AppleCare, Apple Pay, Apple Pay Cash, Apple Card. Apple was founded by Steve Jobs, Steve Wozniak, Ronald Wayne in April 1976 to develop and sell Wozniak's Apple I personal computer, though Wayne sold his share back within 12 days.
It was incorporated as Apple Computer, Inc. in January 1977, sales of its computers, including the Apple II, grew quickly. Within a few years and Wozniak had hired a staff of computer designers and had a production line. Apple went public in 1980 to instant financial success. Over the next few years, Apple shipped new computers featuring innovative graphical user interfaces, such as the original Macintosh in 1984, Apple's marketing advertisements for its products received widespread critical acclaim. However, the high price of its products and limited application library caused problems, as did power struggles between executives. In 1985, Wozniak departed Apple amicably and remained an honorary employee, while Jobs and others resigned to found NeXT; as the market for personal computers expanded and evolved through the 1990s, Apple lost market share to the lower-priced duopoly of Microsoft Windows on Intel PC clones. The board recruited CEO Gil Amelio to what would be a 500-day charge for him to rehabilitate the financially troubled company—reshaping it with layoffs, executive restructuring, product focus.
In 1997, he led Apple to buy NeXT, solving the failed operating system strategy and bringing Jobs back. Jobs pensively regained leadership status, becoming CEO in 2000. Apple swiftly returned to profitability under the revitalizing Think different campaign, as he rebuilt Apple's status by launching the iMac in 1998, opening the retail chain of Apple Stores in 2001, acquiring numerous companies to broaden the software portfolio. In January 2007, Jobs renamed the company Apple Inc. reflecting its shifted focus toward consumer electronics, launched the iPhone to great critical acclaim and financial success. In August 2011, Jobs resigned as CEO due to health complications, Tim Cook became the new CEO. Two months Jobs died, marking the end of an era for the company. Apple is well known for its size and revenues, its worldwide annual revenue totaled $265 billion for the 2018 fiscal year. Apple is the world's largest information technology company by revenue and the world's third-largest mobile phone manufacturer after Samsung and Huawei.
In August 2018, Apple became the first public U. S. company to be valued at over $1 trillion. The company employs 123,000 full-time employees and maintains 504 retail stores in 24 countries as of 2018, it operates the iTunes Store, the world's largest music retailer. As of January 2018, more than 1.3 billion Apple products are in use worldwide. The company has a high level of brand loyalty and is ranked as the world's most valuable brand. However, Apple receives significant criticism regarding the labor practices of its contractors, its environmental practices and unethical business practices, including anti-competitive behavior, as well as the origins of source materials. Apple Computer Company was founded on April 1, 1976, by Steve Jobs, Steve Wozniak, Ronald Wayne; the company's first product is the Apple I, a computer designed and hand-built by Wozniak, first shown to the public at the Homebrew Computer Club. Apple I was sold as a motherboard —a base kit concept which would now not be marketed as a complete personal computer.
The Apple I went on sale in July 1976 and was market-priced at $666.66. Apple Computer, Inc. was incorporated on January 3, 1977, without Wayne, who had left and sold his share of the company back to Jobs and Wozniak for $800 only twelve days after having co-founded Apple. Multimillionaire Mike Markkula provided essential business expertise and funding of $250,000 during the incorporation of Apple. During the first five years of operations revenues grew exponentially, doubling about every four months. Between September 1977 and September 1980, yearly sales grew from $775,000 to $118 million, an average annual growth rate of 533%; the Apple II invented by Wozniak, was introduced on April 16, 1977, at the first West Coast Computer Faire. It differs from its major rivals, the TRS-80 and Commodore PET, because of its character cell-based color graphics and open architecture. While early Apple II models use ordinary cassette tapes as storage devices, they were superseded by the introduction of a 5 1⁄4-inch floppy disk drive and interface called the Disk II.
The Apple II was chosen to be the desktop platform for the first "killer app" of the business world: VisiCalc, a spreadsheet program. VisiCalc created a business market for the Apple II and gave home users an additional reason to buy an Apple II: compatibility with the office. Before VisiCalc, Apple had been a distant third place c
In electrical engineering, capacitive sensing is a technology, based on capacitive coupling, that can detect and measure anything, conductive or has a dielectric different from air. Many types of sensors use capacitive sensing, including sensors to detect and measure proximity and displacement, humidity, fluid level, acceleration. Human interface devices based on capacitive sensing, such as trackpads, can replace the computer mouse. Digital audio players, mobile phones, tablet computers use capacitive sensing touchscreens as input devices. Capacitive sensors can replace mechanical buttons. Capacitive sensors are constructed from many different media, such as copper, indium tin oxide and printed ink. Copper capacitive sensors can be implemented on standard FR4 PCBs as well as on flexible material. ITO allows the capacitive sensor to be up to 90% transparent. Size and spacing of the capacitive sensor are both important to the sensor's performance. In addition to the size of the sensor, its spacing relative to the ground plane, the type of ground plane used is important.
Since the parasitic capacitance of the sensor is related to the electric field's path to ground, it is important to choose a ground plane that limits the concentration of e-field lines with no conductive object present. Designing a capacitance sensing system requires first picking the type of sensing material. One needs to understand the environment the device will operate in, such as the full operating temperature range, what radio frequencies are present and how the user will interact with the interface. There are two types of capacitive sensing system: mutual capacitance, where the object alters the mutual coupling between row and column electrodes, which are scanned sequentially. In both cases, the difference of a preceding absolute position from the present absolute position yields the relative motion of the object or finger during that time; the technologies are elaborated in the following section. In this basic technology, only one side of the insulator is coated with conductive material.
A small voltage is applied to this layer. When a conductor, such as a human finger, touches the uncoated surface, a capacitor is dynamically formed; because of the sheet resistance of the surface, each corner is measured to have a different effective capacitance. The sensor's controller can determine the location of the touch indirectly from the change in the capacitance as measured from the four corners of the panel: the larger the change in capacitance, the closer the touch is to that corner. With no moving parts, it is moderately durable, but has low resolution, is prone to false signals from parasitic capacitive coupling, needs calibration during manufacture. Therefore, it is most used in simple applications such as industrial controls and interactive kiosks. Projected capacitive touch technology is a capacitive technology which allows more accurate and flexible operation, by etching the conductive layer. An X-Y grid is formed either by etching one layer to form a grid pattern of electrodes, or by etching two separate, parallel layers of conductive material with perpendicular lines or tracks to form the grid.
The greater resolution of PCT allows operation with no direct contact, such that the conducting layers can be coated with further protective insulating layers, operate under screen protectors, or behind weather and vandal-proof glass. Because the top layer of a PCT is glass, PCT is a more robust solution versus resistive touch technology. Depending on the implementation, an active or passive stylus can be used instead of or in addition to a finger; this is common with point of sale devices. Gloved fingers may not be sensed, depending on the gain settings. Conductive smudges and similar interference on the panel surface can interfere with the performance; such conductive smudges come from sticky or sweaty finger tips in high humidity environments. Collected dust, which adheres to the screen because of moisture from fingertips can be a problem. There are two types of PCT: self capacitance, mutual capacitance. Mutual capacitive sensors have a capacitor at each intersection of each column. A 12-by-16 array, for example, would have 192 independent capacitors.
A voltage is applied to the columns. Bringing a finger or conductive stylus near the surface of the sensor changes the local electric field which reduces the mutual capacitance; the capacitance change at every individual point on the grid can be measured to determine the touch location by measuring the voltage in the other axis. Mutual capacitance allows multi-touch operation where multiple fingers, palms or styli can be tracked at the same time. Self-capacitance sensors can have the same X-Y grid as mutual capacitance sensors, but the columns and rows operate independently. With self-capacitance, current senses the capacitive load of a finger on each row; this produces a stronger signal than mutual capacitance sensing, but it is unable to resolve more than one finger, which results in "ghosting", or misplaced location sensing. Capacitance is measured indirectly, by using it to control the frequency of an oscillator, or to vary the level of coupling of an AC signal; the design of a simple capacitance meter is based on a re
Personal digital assistant
A personal digital assistant known as a handheld PC, is a variety mobile device which functions as a personal information manager. PDAs were discontinued in the early 2010s after the widespread adoption of capable smartphones, in particular those based on iOS and Android. Nearly all PDAs have the ability to connect to the Internet. A PDA has an electronic visual display. Most models have audio capabilities, allowing usage as a portable media player, enabling most of them to be used as telephones. Most PDAs can access intranets or extranets via Wi-Fi or Wireless Wide Area Networks. Sometimes, instead of buttons, PDAs employ touchscreen technology; the technology industry has recycled the term personal digital assistance. The term is more used for software that identifies a user's voice to reply to the queries; the first PDA, the Organizer, was released in 1984 by Psion, followed by Psion's Series 3, in 1991. The latter began to resemble the more familiar PDA style, including a full keyboard; the term PDA was first used on January 7, 1992 by Apple Computer CEO John Sculley at the Consumer Electronics Show in Las Vegas, referring to the Apple Newton.
In 1994, IBM introduced the first PDA with full telephone functionality, the IBM Simon, which can be considered the first smartphone. In 1996, Nokia introduced a PDA with telephone functionality, the 9000 Communicator, which became the world's best-selling PDA. Another early entrant in this market was Palm, with a line of PDA products which began in March 1996. A typical PDA has a touchscreen for navigation, a memory card slot for data storage, IrDA, Bluetooth and/or Wi-Fi. However, some PDAs may not have a touchscreen, using softkeys, a directional pad, a numeric keypad or a thumb keyboard for input. To have the functions expected of a PDA, a device's software includes an appointment calendar, a to-do list, an address book for contacts, a calculator, some sort of memo program. PDAs with wireless data connections typically include an email client and a Web browser, may or may not include telephony functionality. Many of the original PDAs, such as the Apple Newton and Palm Pilot, featured a touchscreen for user interaction, having only a few buttons—usually reserved for shortcuts to often-used programs.
Some touchscreen PDAs, including Windows Mobile devices, had a detachable stylus to facilitate making selections. The user interacts with the device by tapping the screen to select buttons or issue commands, or by dragging a finger on the screen to make selections or scroll. Typical methods of entering text on touchscreen PDAs include: A virtual keyboard, where a keyboard is shown on the touchscreen. Text is entered by tapping the on-screen keyboard with stylus. An external keyboard connected via Infrared port, or Bluetooth; some users may choose a chorded keyboard for one-handed use. Handwriting recognition, where letters or words are written on the touchscreen with a stylus, the PDA converts the input to text. Recognition and computation of handwritten horizontal and vertical formulas, such as "1 + 2 =", may be a feature. Stroke recognition allows the user to make a predefined set of strokes on the touchscreen, sometimes in a special input area, representing the various characters to be input.
The strokes are simplified character shapes, making them easier for the device to recognize. One known stroke recognition system is Palm's Graffiti. Despite research and development projects, end-users experience mixed results with handwriting recognition systems; some find it frustrating and inaccurate, while others are satisfied with the quality of the recognition. Touchscreen PDAs intended for business use, such as the BlackBerry and Palm Treo also offer full keyboards and scroll wheels or thumbwheels to facilitate data entry and navigation. Many touchscreen PDAs support some form of external keyboard as well. Specialized folding keyboards, which offer a full-sized keyboard but collapse into a compact size for transport, are available for many models. External keyboards may attach to the PDA directly, using a cable, or may use wireless technology such as infrared or Bluetooth to connect to the PDA. Newer PDAs, such as the HTC HD2, Apple iPhone, Apple iPod Touch, Palm Pre, Palm Pre Plus, Palm Pixi, Palm Pixi Plus, Google Android include more advanced forms of touchscreen that can register multiple touches simultaneously.
These "multi-touch" displays allow for more sophisticated interfaces using various gestures entered with one or more fingers. Although many early PDAs did not have memory card slots, now most have either some form of Secure Digital slot, a CompactFlash slot or a combination of the two. Although designed for memory, Secure Digital Input/Output and CompactFlash cards are available that provide accessories like Wi-Fi or digital cameras, if the device can support them; some PDAs have a USB port for USB flash drives. Some PDAs use microSD cards, which are electronically compatible with SD cards, but have a much smaller physical size. While early PDAs connected to a user's personal computer via serial ports or another proprietary connection, many today connect via a USB cable. Older PDAs were unable to connect to each other via USB, as their implementations of USB didn't support acting as the "host"; some early PDAs were able to connect to the Internet indirectly by means of an external modem connected via the PDA's serial port or "sync" connector, or directly by using an expansion card that provided an Ethernet port.
Most modern PDAs have a popular wireless protocol for mobile devices. Bluetooth can be used to connect keyboards, headsets, GPS receiver
In computing, multi-touch is technology that enables a surface to recognize the presence of more than one point of contact with the surface. The origins of multitouch began at CERN, MIT, University of Toronto, Carnegie Mellon University and Bell Labs in the 1970s. Multi-touch was in use as early as 1985. Apple popularized the term "multi-touch" in 2007. Plural-point awareness may be used to implement additional functionality, such as pinch to zoom or to activate certain subroutines attached to predefined gestures; the two different uses of the term resulted from the quick developments in this field, many companies using the term to market older technology, called gesture-enhanced single-touch or several other terms by other companies and researchers. Several other similar or related terms attempt to differentiate between whether a device can determine or only approximate the location of different points of contact to further differentiate between the various technological capabilities, but they are used as synonyms in marketing.
In computing, multi-touch is technology which enables a trackpad or touchscreen to recognize more than one or more than two points of contact with the surface. Apple popularized the term "multi-touch" in 2007 with which it implemented additional functionality, such as pinch to zoom or to activate certain subroutines attached to predefined gestures; the two different uses of the term resulted from the quick developments in this field, many companies using the term to market older technology, called gesture-enhanced single-touch or several other terms by other companies and researchers. Several other similar or related terms attempt to differentiate between whether a device can determine or only approximate the location of different points of contact to further differentiate between the various technological capabilities, but they are used as synonyms in marketing; the use of touchscreen technology predates the personal computer. Early synthesizer and electronic instrument builders like Hugh Le Caine and Robert Moog experimented with using touch-sensitive capacitance sensors to control the sounds made by their instruments.
IBM began building the first touch screens in the late 1960s. In 1972, Control Data released the PLATO IV computer, a terminal used for educational purposes, which employed single-touch points in a 16×16 array user interface; these early touchscreens only registered one point of touch at a time. On-screen keyboards were thus awkward to use, because key-rollover and holding down a shift key while typing another were not possible. An exception was a multi-touch reconfigurable touchscreen keyboard/display developed at the Massachusetts Institute of Technology in the early 1970s. In 1977, one of the early implementations of mutual capacitance touchscreen technology was developed at CERN based on their capacitance touch screens developed in 1972 by Danish electronics engineer Bent Stumpe; this technology was used to develop a new type of human machine interface for the control room of the Super Proton Synchrotron particle accelerator. In a handwritten note dated 11 March 1972, Stumpe presented his proposed solution – a capacitive touch screen with a fixed number of programmable buttons presented on a display.
The screen was to consist of a set of capacitors etched into a film of copper on a sheet of glass, each capacitor being constructed so that a nearby flat conductor, such as the surface of a finger, would increase the capacitance by a significant amount. The capacitors were to consist of fine lines etched in copper on a sheet of glass – fine enough and sufficiently far apart to be invisible. In the final device, a simple lacquer coating prevented the fingers from touching the capacitors. In 1976, MIT described a keyboard with variable graphics capable of multi-touch detection, for what is likely to be the first multitouch screen. In the early 1980s, The University of Toronto's Input Research Group were among the earliest to explore the software side of multi-touch input systems. A 1982 system at the University of Toronto used a frosted-glass panel with a camera placed behind the glass; when a finger or several fingers pressed on the glass, the camera would detect the action as one or more black spots on an otherwise white background, allowing it to be registered as an input.
Since the size of a dot was dependent on pressure, the system was somewhat pressure-sensitive as well. Of note, this system was not able to display graphics. In 1983, Bell Labs at Murray Hill published a comprehensive discussion of touch-screen based interfaces, though it makes no mention of multiple fingers. In the same year, the video-based Video Place/Video Desk system of Myron Krueger was influential in development of multi-touch gestures such as pinch-to-zoom, though this system had no touch interaction itself. By 1984, both Bell Labs and Carnegie Mellon University had working multi-touch-screen prototypes – both input and graphics – that could respond interactively in response to multiple finger inputs; the Bell Labs system was based on capacitive coupling of fingers, whereas the CMU system was optical. In 1985, the canonical multitouch pinch-to-zoom gesture was demonstrated, with coordinated graphics, on CMU's system. In October 1985, Steve Jobs signed a non-disclosure agreement to tour CMU's Sensor Frame multi-touch lab.
In 1990, Sears et al. published a review of academic research on single and multi-touch touchscreen human–computer interaction of the time, describing single touch gestures such as rotating knobs, swiping the screen to activate a switch, an