The flip-disc display (or flip-dot display) is an electromechanical dot matrix display technology used for large outdoor signs, normally those that will be exposed to direct sunlight. Flip-disc technology has been used for destination signs in buses across North America, Europe and Australia, as well as for variable-message signs on highways. It has also been used extensively on public information displays.A few game shows have also used flip-disc displays, including Canadian shows like Just Like Mom , The Joke's on Us and Uh Oh! , but most notably the American game show Family Feud from 1976 to 1995 and its British version Family Fortunes from 1980 to 2003.
A destination sign or destination indicator/destination blind is a sign mounted on the front, side or rear of a public transport vehicle, such as a bus, tram/streetcar or light rail vehicle, that displays the vehicle's route number and destination, or the route's number and name on transit systems using route names. The main such sign, mounted on the front of the vehicle, usually located above the windshield, is often called the headsign, most likely from the fact that these signs are located on the front, or head, end of the vehicle. Depending on the type of the sign, it might also display intermediate points on the current route, especially if the route is particularly long and its final terminus by itself is not very helpful in determining where the vehicle is going.
North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It is also considered by some to be a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea.
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, Asia to the east, and the Mediterranean Sea to the south. It comprises the westernmost part of Eurasia.
The flip-disc display consists of a grid of small metal discs that are black on one side and a bright color on the other (typically white or day-glo yellow), set into a black background. With power applied, the disc flips to show the other side. Once flipped, the discs will remain in position without power.
The disc is attached to an axle which also carries a small permanent magnet. Positioned close to the magnet is a solenoid. By pulsing the solenoid coil with the appropriate electrical polarity, the permanent magnet on the axle will align itself with the magnetic field, also turning the disc. Another style uses a magnet embedded in the disc itself, with separate solenoids arranged at the ends or side to flip it.
A solenoid is a coil wound into a tightly packed helix. The term was invented in 1823 by André-Marie Ampère to designate a helical coil.
Electrical polarity is a term used throughout industries and fields that involve electricity. There are two types of poles: positive (+) and negative (−). This represents the electrical potential at the ends of a circuit. A battery has a positive terminal and a negative terminal. Interconnection of electrical device nearly always require correct polarity to be maintained. Correct polarity is essential for the operation of vacuum tube and semiconductor devices, many electric motors, electrochemical cells, electrical instruments, and other devices.
A magnetic field is a vector field that describes the magnetic influence of electric charges in relative motion and magnetized materials. Magnetic fields are observed in a wide range of size scales, from subatomic particles to galaxies. The effects of magnetic fields are commonly seen in permanent magnets, which pull on magnetic materials and attract or repel other magnets. Magnetic fields surround and are created by magnetized material and by moving electric charges such as those used in electromagnets. Magnetic fields exert forces on nearby moving electrical charges and torques on nearby magnets. In addition, a magnetic field that varies with location exerts a force on magnetic materials. Both the strength and direction of a magnetic field vary with location. As such, it is an example of a vector field.
A computerized driver system reads data, typically characters, and flips the appropriate discs to produce the desired display. Some displays use the other end of the solenoid to actuate a reed switch, which controls an LED array behind the disc, resulting in a display that is visible at night but requires no extra drive electronics.
The reed switch is an electrical switch operated by an applied magnetic field. It was invented at Bell Telephone Laboratories in 1936 by Walter B. Ellwood. In its simplest and most common form, it consists of a pair of ferromagnetic flexible metal reeds contacts in a hermetically sealed glass envelope. The contacts are usually normally open, closing when a magnetic field is present, or they may be normally closed and open when a magnetic field is applied. The switch may be actuated by an electromagnetic coil, making a reed relay, or by bringing a permanent magnet near the switch. When the magnetic field is removed, the reeds in the reed switch return to their original position.
Various driving schemes are in use. Their basic purpose is to reduce the amount of wiring and electronics needed to drive the solenoids. All common methods connect the solenoids in some sort of matrix. One driving method is similar to that of core memory: the solenoids are connected in a simple matrix. Those solenoids at the crossing point of two powered wires are driven with enough current to flip their discs; those powered on only the vertical or horizontal line see only 1/2 of the required force (as flux is proportional to current, which in turn is proportional to the voltage). Those on unpowered lines also do not flip.
An electric current is the rate of flow of electric charge past a point or region. An electric current is said to exist when there is a net flow of electric charge through a region. In electric circuits this charge is often carried by electrons moving through a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionized gas (plasma).
In electromagnetism, electric flux is the measure of the electric field through a given surface, although an electric field in itself cannot flow. It is a way of describing the electric field strength at any distance from the charge causing the field.
Voltage, electric potential difference, electric pressure or electric tension is the difference in electric potential between two points. The difference in electric potential between two points in a static electric field is defined as the work needed per unit of charge to move a test charge between the two points. In the International System of Units, the derived unit for voltage is named volt. In SI units, work per unit charge is expressed as joules per coulomb, where 1 volt = 1 joule per 1 coulomb. The official SI definition for volt uses power and current, where 1 volt = 1 watt per 1 ampere. This definition is equivalent to the more commonly used 'joules per coulomb'. Voltage or electric potential difference is denoted symbolically by ∆V, but more often simply as V, for instance in the context of Ohm's or Kirchhoff's circuit laws.
Typically, the driving scheme works its way from top to bottom, powering each horizontal line "on" and then powering the needed vertical lines to set up that row. The whole process takes a few seconds, during which time the sound of the discs being flipped over is quite distinctive.
Other driving schemes use diodes to isolate non-driven solenoids, which allows only the discs whose state need changing to be flipped. This uses less power, and may be more robust.
A diode is a two-terminal electronic component that conducts current primarily in one direction ; it has low resistance in one direction, and high resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other materials such as gallium arsenide and germanium are used.
The flip-disc display was developed by Kenyon Taylor at Ferranti-Packard at the request of Trans-Canada Airlines (today's Air Canada). By the time the system had been patented in 1961, TCA had already lost interest and Ferranti's management didn't consider the project very interesting.
The first big opportunity for this system came in 1961 when the Montreal Stock Exchange decided to modernize its method of displaying trading information. equivalent to $6,000,000in 2018) was beset by delays and technical problems, but once it became fully operational it was considered very reliable.Ferranti-Packard and Westinghouse both bid on the project, Westinghouse using an electro-luminescent technology. Ferranti won the contract after demonstrating the system with a mock-up they built in a disused warehouse across the street from the exchange's new offices, using hand-painted dots moved by hand to show how the system would work. The dots were slowly replaced with operating modules as they became available. The $700,000 system (
The systems were relatively expensive because of their manual construction, typically completed by women who "sewed" the displays in a fashion very similar to the construction of core memory. Worse, Ferranti signed maintenance contracts that were, by 1971, losing $12,000 a month.A re-organization of the engineering and maintenance department addressed the problems, and prices started to fall. By 1977 the system had won sales with half the world's major stock exchanges.
As prices fell, they were soon found in wider roles, notably that of highway signs and information systems for public transport. In Europe and in the US, vane displays based on the same technology became popular for displaying prices at gasoline stations. In 1974 Ferranti started a project to build smaller versions for the front of buses and trains, and by 1977 revenue from these had already surpassed that from other lines of business.The displays often required minor maintenance to free up "stuck" discs.
Flip-disc systems are still widespread but are not often found in new installations. Their place has been filled by LED-based products, which use a small amount of power constantly rather than each time the message changes, but are easily visible in light and darkness and, having no moving parts, require little maintenance.
Some producers offer combined displays which use flip-dot and LED technologies together (every dot-disc has its own LED) and thereby they combine their advantages. For example, the Czech company BUSE from Blansko supplies self-patented DOT-LED displays (only DOT and only LED as well) in Central and East Europe.This combined technology was used for outside displays of most of new buses and trams.
Prague is the capital and largest city in the Czech Republic, the 14th largest city in the European Union and the historical capital of Bohemia. Situated in the north-west of the country on the Vltava river, the city is home to about 1.3 million people, while its metropolitan area is estimated to have a population of 2.6 million. The city has a temperate climate, with warm summers and chilly winters.
In electricity generation, a generator is a device that converts motive power into electrical power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines and even hand cranks. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday. Generators provide nearly all of the power for electric power grids.
The Czech Republic has become one of the major tourist destinations in Europe, receiving over 20 million visitors yearly. The capital, Prague, is the most popular destination, by itself receiving over 8 million visitors annually out of which almost 7 million are foreign. Other highly visited destinations include Karlštejn Castle, Kutná Hora, Brno, Český Krumlov, České Budějovice, Olomouc and the Lednice–Valtice Cultural Landscape. Prague attracts large numbers of foreign tourists, mostly from Germany, Russia, Poland, the United States, Israel and the United Kingdom.
Twistor memory is a form of computer memory formed by wrapping magnetic tape around a current-carrying wire. Operationally, twistor was very similar to core memory. Twistor could also be used to make ROM memories, including a re-programmable form known as piggyback twistor. Both forms were able to be manufactured using automated processes, which was expected to lead to much lower production costs than core-based systems.
Flat-panel displays are electronic viewing technologies used to enable people to see content in a range of entertainment, consumer electronics, personal computer, and mobile devices, and many types of medical, transportation and industrial equipment. They are far lighter and thinner than traditional cathode ray tube (CRT) television sets and video displays and are usually less than 10 centimetres (3.9 in) thick. Flat-panel displays can be divided into two display device categories: volatile and static. Volatile displays require that pixels be periodically electronically refreshed to retain their state. A volatile display only shows an image when it has battery or AC mains power. Static flat-panel displays rely on materials whose color states are bistable, and as such, flat-panel displays retain the text or images on the screen even when the power is off. As of 2016, flat-panel displays have almost completely replaced old CRT displays. In many 2010-era applications, specifically small portable devices such as laptops, mobile phones, smartphones, digital cameras, camcorders, point-and-shoot cameras, and pocket video cameras, any display disadvantages of flat-panels are made up for by portability advantages.
A variable-message sign, often abbreviated VMS, CMS, or DMS, and in the UK known as a matrix sign, is an electronic traffic sign often used on roadways to give travellers information about special events. Such signs warn of traffic congestion, accidents, incidents such as terrorist attacks, AMBER/Silver/Blue Alerts, roadwork zones, or speed limits on a specific highway segment. In urban areas, VMS are used within parking guidance and information systems to guide drivers to available car parking spaces. They may also ask vehicles to take alternative routes, limit travel speed, warn of duration and location of the incidents, or just inform of the traffic conditions.
A sixteen-segment display (SISD) is a type of display based on 16 segments that can be turned on or off according to the graphic pattern to be produced. It is an extension of the more common seven-segment display, adding four diagonal and two vertical segments and splitting the three horizontal segments in half. Other variants include the fourteen-segment display which does not split the top or bottom horizontal segments, and the twenty two-segment display that allows lower-case characters with descenders.
A transit bus is a type of bus used on shorter-distance public transport bus services. Several configurations are used, including low-floor buses, high-floor buses, double-decker buses, articulated buses and midibuses.
Ferranti-Packard Ltd. was the Canadian division of Ferranti's global manufacturing empire, formed by the 1958 merger of Ferranti Electric and Packard Electric. For several years in the post-war era, the company underwent dramatic expansion and repeatedly almost became a major computer supplier, but eventually shed various divisions and returned to becoming an electrical grid supplier once again. The company was purchased in 1998 by the Austrian company, VA TECH. On July 23, 2005 Siemens PTD purchased VA Tech’s Transmission and Distribution Division (T&D) group for transformers and switchgear.
A dot-matrix display is an electronic digital display device that displays information on machines, clocks and watches, public transport departure indicators and many other devices requiring a simple alphanumeric display device of limited resolution.
A passenger information [display] system is an automated system for supplying users of public transport with information about the nature and state of a public transport service, through visual, voice or other media. They are also known as Customer Information Systems and Operational Information Systems. Among the information provided by such systems, a distinction can be drawn between:
A split-flap display, or sometimes simply flap display, is an electromechanical display device that presents changeable alphanumeric text, and occasionally fixed graphics.
Multiplexed displays are electronic display devices where the entire display is not driven at one time.
Maurice Kenyon Taylor was a British electrical engineer and inventor responsible for many diverse technological developments and inventions, producing over 70 patents during his career.
A LED display is a flat panel display that uses an array of light-emitting diodes as pixels for a video display. Their brightness allows them to be used outdoors where they are visible in the sun for store signs and billboards. In recent years, they have also become commonly used in destination signs on public transport vehicles, as well as variable-message signs on highways. LED displays are capable of providing general illumination in addition to visual display, as when used for stage lighting or other decorative purposes.
Electrically operated display devices have developed from electromechanical systems for display of text, up to all-electronic devices capable of full-motion 3D color graphic displays. Electromagnetic devices, using a solenoid coil to control a visible flag or flap, were the earliest type, and were used for text displays such as stock market prices and arrival/departure display times. The cathode ray tube was the workhorse of text and video display technology for several decades until being displaced by plasma, liquid crystal (LCD) and solid-state devices such as LEDs and OLEDs. With the advent of microprocessors and microelectronic devices, many more individual picture elements ("pixels") could be incorporated into one display device, allowing graphic displays and video.
A text display is an electronic alphanumeric display device that is mainly or only capable of showing text, or extremely limited graphic characters. This includes electromechanical split-flap displays, vane displays, and flip-disc displays; all-electronic liquid-crystal displays, incandescent eggcrate displays, LED displays, and vacuum fluorescent displays; and even electric nixie tubes.
A vehicle tracking system combines the use of automatic vehicle location in individual vehicles with software that collects these fleet data for a comprehensive picture of vehicle locations. Modern vehicle tracking systems commonly use GPS or GLONASS technology for locating the vehicle, but other types of automatic vehicle location technology can also be used. Vehicle information can be viewed on electronic maps via the Internet or specialized software. Urban public transit authorities are an increasingly common user of vehicle tracking systems, particularly in large cities.
The iBus is an Automatic Vehicle Location (AVL) system to improve London's buses using technology installed by Siemens AG. The system tracks all of London's 8000 buses to provide passengers with audio visual announcements, improved information on bus arrivals, and to trigger priority at traffic junctions.
|Wikimedia Commons has media related to Flip-dot displays .|