AU2006201825B2

AU2006201825B2 - Variable Message Sign

Info

Publication number: AU2006201825B2
Application number: AU2006201825A
Authority: AU
Inventors: Cliff Jeffries; Jean Marie Gilbert Malepa
Original assignee: Roads and Traffic Authority of New South Wales
Current assignee: ROADS AND MARITIME SERVICES
Priority date: 2005-05-02
Filing date: 2006-05-02
Publication date: 2012-01-19
Anticipated expiration: 2026-05-02
Also published as: AU2006201825A1

Abstract

A variable message sign includes a plurality of pixel construction elements disposed in a substantially planar array wherein each pixel construction element is in communication with each other pixel construction element adjacent thereto in the array and where each pixel construction element includes a display face having at least one light emitting pixel. A slave processor is disposed in each pixel construction element and configured for controlling the at least one light emitting pixel and the communication with adjacent pixel construction elements. A master processor is disposed remotely from the pixel construction elements and in communication with a central pixel construction element where the master processor communicates with each slave processor via a communication path from the central pixel construction element to each of the slave processors through the connections between adjacent pixel construction elements. A method of operating a variable message sign is also disclosed.

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: ROADS & TRAFFIC AUTHORITY OF NEW SOUTH WALES Actual Inventor(s): Jean Marie Gilbert MALEPA Cliff JEFFRIES Address for Service: FRASER OLD & S01N Patent Attorneys Level 6, 118 Alfred Street MILSONS POINT NSW 2061 Invention Title: "Variable Message Sign" Details of Basic Application(s): 2005 902 201 filed 2 May 2005 The following statement is a full description of this invention, including the best method of performing it known to us: 2 VARIABLE MESSAGE SIGN FIELD OF THE INVENTION The invention relates to message signs and, in particular, to variable message 5 signs. The invention has been developed primarily for use in roadside variable message signs and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular 10 field of use. BACKGROUND OF THE INVENTION Variable message roadside display signs are well known. The known signs range in size depending on the message to be displayed and the location of the sign. 15 Permanent roadside display signs are most often required to be viewed from a relatively long distance by a driver. As a result, the size of these conventional signs and the individual light emitting elements need to possess certain visual properties, as well as the ability to be permanently exposed. 20 Conventional signs have aimed to overcome the expense and difficulty associated with making and maintaining such roadside display signs. US Pat. No. 5,390,093 discloses the use of a plurality of display elements disposed in a planar array. A square lattice support grid defines a base surface to retain a plurality of display devices. In this way, standard grid and display sizes can be used for signs of 25 various sizes being a multiple of the standard. Unfortunately, the support grid is made from a metal material and cannot be easily scaled up or down to provide a sign having display devices in a grid that is larger than the support grid, or smaller where parts of the grid will remain exposed. 30 Further, the scaling of a sign to a larger sign either with or without additional light emitting pixels is not easily achieved as the sign controller needs significant re configuration to accept further display elements.

3 OBJECT OF THE INVENTION It is an object of the present invention to provide a variable message sign and method of operating the sign that will overcome or substantially ameliorate any one or more of the disadvantages of the prior art, or to provide a useful alternative. 5 SUMMARY OF THE INVENTION According to a first aspect of the invention there is provided a variable message sign including: a plurality of pixel construction elements disposed in a substantially planar 10 array wherein each pixel construction element is in communication with each other pixel construction element adjacent thereto in the array, each pixel construction element including a display face having at least one light emitting pixel; a slave processor disposed in association with each pixel construction 15 element and configured for controlling the at least one light emitting pixel and the communication with adjacent pixel construction elements; and a master processor disposed remotely from the pixel construction elements and in communication with a central pixel construction element wherein the master processor communicates with each slave processor via a communication 20 path from the central pixel construction element to each of the slave processors through the connections between adjacent pixel construction elements. According to a second aspect of the invention there is provided a variable message sign including: 25 a plurality of pixel construction elements disposed in a substantially planar array wherein each pixel construction element is in communication with each other pixel construction element adjacent thereto in the array, each pixel construction element including a display face having at least one light emitting pixel; 30 a slave processor disposed in association with each pixel construction element and configured for controlling the at least one light emitting pixel and the communication with adjacent pixel construction elements; and 4 a master processor disposed remotely from the pixel construction elements and in communication with two or more central pixel construction elements wherein each central pixel construction element is configured to communicate with different predetermined numbers of pixel construction element such that the 5 master processor communicates with each predetermined number of slave processors via a communication path from each central pixel construction element to each of the slave processors through the connections between adjacent pixel construction elements. 10 According to a third aspect of the invention there is provided a method of operating a variable message sign, the method including the steps of: disposing plurality of pixel construction elements in a planar array, each pixel construction element including a slave processor; disposing at least one light emitting pixel element on a display face of each 15 pixel construction element; connecting each pixel construction element to each pixel construction element adjacent thereto in the array; and connecting a master processor to a central pixel construction element; and communicating pixel construction element control signals from the master 20 processor to the central pixel construction element to each slave processor. According to another aspect of the invention there is provided a method of operating a variable message sign, the method including the steps of: disposing plurality of pixel construction elements in a planar array, each 25 pixel construction element including a slave processor; disposing at least one light emitting pixel element on a display face of each pixel construction element; connecting each pixel construction element to each pixel construction element adjacent thereto in the array; 30 connecting a master processor to two or more central pixel construction elements such that each central pixel construction element is configured to 5 communicate with different predetermined numbers of pixel construction elements; and communicating pixel construction element control signals from the master processor to the central pixel construction elements to each slave processor via the 5 communication path between pixel construction elements. It can therefore be seen that the variable message sign, and the method of operation, provides a sign which is formed from an array of pixel construction elements where the non-operability of any one pixel construction element utilises a 10 different communication path to other pixel construction elements. Further, it can be seen that the variable message sign can be made of any number of pixel construction elements to provide a predetermined display area, and that the non functioning of any pixel construction element or light emitting pixel(s) can be compensated for by the master processor. 15 BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: FIG. 1 is a schematic view of part of a variable message sign according to 20 the preferred embodiment; FIG. 2 is another schematic view of part of the variable message sign of FIG. 1; and FIG. 3 is a schematic firmware diagram of the variable message sign of FIG. 1. 25 DETAILED DESCRIPTION Referring to FIG. 1, there is shown a schematic view of part of a variable message sign 1. The sign 1 includes a plurality of substantially rectangular pixel construction elements 3 each having a display face 5. 30 The pixel construction elements 3 are disposed in a rectangular array with the display faces 5 facing substantially the same direction. Each pixel construction 6 element 3 is connected to a rail power supply 9. The power supplied to the rails 9 can be AC or DC as desired. The display face 5 of each pixel construction element 3 includes a plurality of light 5 emitting diode (LED) pixels (not illustrated) disposed in a rectangular array over the display face 5. The LEDs point in substantially the same direction. Each pixel construction element 3 in the rectangular array is in communication with each other pixel construction element 3 adjacent to it in the array by means of 10 a channel or generic connection 7. In FIG. 1, a connection is shown as a transmission connection, Tx, and a receiver connection, Rx. It is noted that any preferred communication connection can be advantageously employed. A slave processor 11, best shown in FIG. 3, is disposed in each pixel construction 15 element 3. Each slave processor 11 is configured for controlling the LED pixels in each pixel construction element 3 and controlling the communication between adjacent pixel construction elements 3 in the rectangular array. A master processor (not illustrated) is disposed remotely from the array of pixel 20 construction elements 3. The master processor is in communication with a central pixel construction element denoted 3C in the FIGS. The master processor is configured to communicate with each slave processor 11 via a communication path from the central pixel construction element 3C to each of the slave processors 11 through connections 7 between adjacent pixel construction elements 3. 25 In use, the master processor interrogates the operational status of each slave processor II by sending interrogation signals to each slave processor 11 via the central pixel construction element 3C, and receiving a response signal from each processor 11 via the pixel construction element 3C. The response signals sent 30 from each pixel construction element 3 are indicative of the operational status of each pixel construction element 3 and their LED pixels.

7 The master processor also provides display signals to each slave processor 11 via the communication path from the central pixel construction element 3C to each slave processor 11. The display signals control the emission of light from each LED pixel in each pixel construction element 3. The display signals include 5 timing information so that each pixel construction element 3 LED pixels emit light in a coordinated manner to provide a display. The LED pixels are operable to emit light of varying intensity. The master processor is also configured to communicate an alert signal to a user or 10 a log in response to the receipt of signals indicating the operative failure of any pixel construction element 3 to communicate with any adjacent pixel construction element 3 in the square array. The master processor is also configured to communicate an alert signal in response to the operational failure of a predetermined number of LED pixels on a display face 5 of any pixel construction 15 element 3. When a signal is received by the master processor indicative of a failed communication path between adjacent pixel construction elements 3, the master processor stores this information and signals previously communicated between 20 the failed communication path are re-routed via another path. When a signal is received by the master processor indicative of the failure of the predetermined number of LED pixels, the pixel construction elements 3 in the sign I can be re configured to compensate for the missing LED pixels. For example, text or a part thereof displayed on the sign 1 can be re-configured to use only functional pixel 25 construction elements 3. In response to an operational failure of a pixel construction element 3 or the predetermined number of LED pixels on the display face 5 of the element 3, the entire failed pixel construction element 3 can be replaced without needing to re 30 configure the master processor. This is achieved by determining the slave processor positions relative to the other slave processors.

An operation failure of LED pixels, for example, can be easily determined by testing each LED or array of LEDs with power applied and without power. If the LED pixels are provided signals to emit light, a voltage drop or current flow is expected. The absence of this is used to indicate a failed pixel. Further, the 5 voltage drop over, or current flow through, each LED pixel when in the off state should be zero so that any indication otherwise designates a failed LED pixel or pixels. Such probing can be automatically conducted or in response to the actuation of a test switch 17. 10 The sign I is disposed in a sealed housing 13 shown in FIG. 3. The housing includes a temperature sensor 15 in communication with the master processor. The temperature sensor 15 provides an output indicative of the temperature of the pixel construction elements 3 and the inside of the housing. When the temperature senor provides an output that the measured temperature exceeds a predetermined 15 value, all power to the sign 1 is cut until the temperature drops below a predetermined value or a cooling fan (not illustrated) or the like instigated to reduce the temperature with the housing 13. A status indicator (not illustrated) is also disposed on a rear face of each pixel 20 construction element 3. The indicator is configured to provide a signal viewable through the rear of the housing of the correct operation of each pixel construction element 3 and LED pixels. Although not illustrated, the master controller automatically detects the presence 25 of operative pixel construction elements 3 and configures a communication path from the central pixel construction element 3 to each slave processor accordingly. In this way, a smaller or larger array of pixel construction elements 3 can be provided without re-configuring the master processor. 30 Also not illustrated, the remote processor is operated by a computer in communication therewith over a computer network, but it can also be user operated. In this way, a user does not need to be at the sign or the site of the 9 remote processor to make changes to the displayed message or the sign configuration, or in diagnosing any problems with the sign 1. Furthermore, the remote processor transmits an alert signal to the computer network for automatic detection. 5 Referring to FIG. 2, as an example, a rectangular array of pixel construction elements 3 is provided by disposing 240 rows by 240 columns of pixel construction elements 3 in a rectangular array (only part of the array is shown) where each pixel construction element 3 is in communication with each adjacent 10 pixel construction element 3. Each pixel construction element 3 has a rectangular array of 9 rows by 7 columns of light emitting LED pixels (not illustrated). Each LED pixel can be driven to output 16 different levels of luminosity which is driven by a pulse width modulated power supply. 15 The slave processor 11 in each pixel construction element 3 in the example includes four full duplex channels or serial ports for communication with each adjacent pixel construction element 3. A three channel 10-bit analogue to digital converter is included with the processor, together with RAM and input/output ports. Firmware for operating ROM is loaded into the slave processor and can be 20 upgraded remotely via the master processor. In FIG. 2, the array of pixel construction elements 3 forming part of the sign 1 is shown. Each pixel construction element 3 is given a unique address corresponding to its location in the array. The bottom left pixel construction element 3 has the 25 address (1,1) with the others addressed as shown. For a general pixel construction element 3 having an address (x,y), the four adjacent addresses moving clockwise from the top are (x,y+1); (x-1,y); (x,y-1); and (x+1,y). A structure of a network packet can be provided as follows: 30 Broadcast: 1,x:5, y:5, len:5, Data[n], CRC:16 where the broadcast bit set on I indicates the data packet goes to all pixel construction elements 3; x & y represent the location of the destination pixel 1U construction element 3; len is the number of bytes in the data packet with an upper length of 32bytes; and CRC is the checksum of the data packet. The network data packet will update the memory image of desired LED pixel 5 states. The slave processor 11 will be updated on the next pixel display update clock cycle. The master processor also controls the display of animation and scrolling, so the message displayed on the sign will be sent out as frequently as required. All pixel construction elements 3 are synchronised so that LED pixel updates occur simultaneously across the entire sign. 10 In this example, a status update message will be periodically generated by the master processor to determine if a pixel construction element 3 is functional. A non-functioning pixel construction element 3 will be detected by a timeout mechanism in the master processor where any pixel construction element 3 not 15 reporting to the master processor within a predetermined period of time will be assumed to be defective. A number of distinct status update messages may be required. For instance, the pixel status itself requires 63 by 2 bits in this example. It is noted that in other embodiments, not illustrated, the master processor is 20 configured for communication with all pixel construction elements 3 in any row or column of the square array. In such embodiments, one pixel construction element 3 in the row or column is configured to be the central pixel construction element 3C. In the event that the central pixel construction element 3C fails to communicate with the master processor or adjacent pixel construction elements 3, 25 or if the number of LED pixels falls below the predetermine value, the master processor re-configures another pixel construction element 3 in the row or column to become the central pixel construction element 3C. This will minimise the likelihood of the master processor losing communication with the slave processors. 30 Further, it will be appreciated that the master processor can be used to communicate with two or more central pixel elements simultaneously. In such 11 cases, each central pixel construction element is configured to control a predetermined number of pixel construction elements. The master processor communicates with each predetermined number of slave processors via a communication path from each central pixel construction element to each of the 5 slave processors through the connections between adjacent pixel construction elements. In this way, the failure of one or more of the central pixel construction elements causes the master processor to also communicate signals for the failed central pixel elements to the functional central pixel construction elements. This provides an additional level of redundancy required for signs used in remote areas 10 or difficult to access locations. It is also noted that the pixel construction elements 3 can be disposed in other regular two-dimensional arrays such as triangular or polygonal, or in an irregular two-dimensional array. Further, the light emitting pixels can be in a circular or 15 polygonal array, or other preferred regular or non-regular array. The foregoing describes only one embodiment of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention. 20

Claims

1. A variable message sign including: a plurality of pixel construction elements disposed in a substantially planar array wherein each pixel construction element is in communication with each other pixel construction element adjacent thereto in the array, each pixel construction element including a display face having at least one light emitting pixel; a slave processor disposed in association with each pixel construction element and configured for controlling the at least one light emitting pixel and the communication with adjacent pixel construction elements; and a master processor disposed remotely from the pixel construction elements and in communication with a central pixel construction element wherein the master processor communicates with each slave processor via a communication path from the central pixel construction element to each of the slave processors through the connections between adjacent pixel construction elements.

2. A variable message sign according to claim 1 wherein the pixel construction elements are rectangular and are disposed in a rectangular planar array, each pixel construction element including a plurality of light emitting pixels disposed in a circular or polygonal array.

3. A variable message according to claim 2 wherein the master processor interrogates the operational status of each pixel construction element and respective light emitting pixels and provides signals for the control of the emission of light from the pixel construction element light emitting pixels.

4. A variable message sign according to claim 3 wherein the master processor is in communication with each pixel construction element in a row or column of the array wherein any one of the plurality pixel construction elements in the row or column is configured to be the central pixel construction element such that the operative failure of the configured central pixel construction element to communicate with each adjacent pixel construction element or the master processor causes the master processor to configure another one of the pixel construction elements in the row or column to become the central pixel construction element.

5. A variable message sign according to claim 3 or 4 wherein the master processor is configured to communicate an alert when any pixel construction 13 element fails to communicate with any adjacent pixel construction element or in response to the operational failure of a predetermined number of light emitting pixels on any one pixel construction element.

6. A variable message sign according to any one of the preceding claims wherein the intensity of any pixel construction element light emitting pixel is variable.

7. A variable message sign according to claim 6 wherein the varying of the light emitting pixel intensity is synchronised with the master processor.

8. A variable message according to claim 3 wherein the interrogation of the pixel construction element light emitting pixels includes observing the current and/or voltage thereof such that failure is indicated by failure of a light emitting pixel to draw power when in an ON state or to keep drawing current when in an OFF state.

9. A variable message sign according to any one of the preceding claims and disposed within a housing having a housing temperature sensor in communication with the master processor such that power to the sign is removed in response to the sensed temperature exceeding a predetermined value, and a rear of the housing including a visual indication of the operational status of each pixel construction element.

10. A variable message sign according to claim 1 wherein the pixel construction elements are in communication with adjacent pixel construction elements over a communication channel or generic connection.

11. A variable message sign according to claim 1 wherein power is supplied to each pixel construction element in parallel arrangement.

12. A variable message sign including: a plurality of pixel construction elements disposed in a substantially planar array wherein each pixel construction element is in communication with each other pixel construction element adjacent thereto in the array, each pixel construction element including a display face having at least one light emitting pixel; a slave processor disposed in association with each pixel construction element and configured for controlling the at least one light emitting pixel and the communication with adjacent pixel construction elements; and 14 a master processor disposed remotely from the pixel construction elements and in communication with two or more central pixel construction elements wherein each central pixel construction element is configured to communicate with different predetermined numbers of pixel construction element such that the master processor communicates with each predetermined number of slave processors via a communication path from each central pixel construction element to each of the slave processors through the connections between adjacent pixel construction elements.

13. A variable message sign according to claim 12 wherein failure of one or more of the central pixel construction elements causes the master processor to also communicate signals for the failed central pixel elements to the functional central pixel construction elements.

14. A method of operating a variable message sign, the method including the steps of: disposing plurality of pixel construction elements in a planar array, each pixel construction element including a slave processor; disposing at least one light emitting pixel element on a display face of each pixel construction element; connecting each pixel construction element to each pixel construction element adjacent thereto in the array; and connecting a master processor to a central pixel construction element; and communicating pixel construction element control signals from the master processor to the central pixel construction element to each slave processor.

15. A method of operating a variable message sign according to claim 14 including the step of providing interrogation signals from the master processor to each pixel construction element, the interrogation signals being returned by each pixel construction element and including data indicative of the operational status of each pixel construction element and the light emitting pixels.

16. A method according to claim 15 including the step of connecting the master processor to each pixel construction element in a row or column of the array and configuring any one of the pixel construction elements in the row or column to be the initial central pixel construction element, and re-configuring another one of the 13 pixel construction elements in the row or column to become the central pixel construction element in response to the operative failure of the initial pixel construction element.

17. A method of operating a variable message sign, the method including the steps of: disposing plurality of pixel construction elements in a planar array, each pixel construction element including a slave processor; disposing at least one light emitting pixel element on a display face of each pixel construction element; connecting each pixel construction element to each pixel construction element adjacent thereto in the array; connecting a master processor to two or more central pixel construction elements such that each central pixel construction element is configured to communicate with different predetermined numbers of pixel construction elements; and communicating pixel construction element control signals from the master processor to the central pixel construction elements to each slave processor via the communication path between pixel construction elements.

18. A method according to claim 17 wherein in response to the failure of one or more of the central pixel construction elements, the signals from the master processor intended for the failed central pixel elements are communicated to functional central pixel construction elements.

19. A variable message sign being substantially as herein described with reference to the accompanying drawings.

20. A pixel construction element being substantially as herein described with reference to the accompanying drawings.

21. A method of providing a variable message sign, the method being substantially as herein described with reference to the accompanying drawings. Dated this 25th day of November 2011 ROADS & TRAFFIC AUTHORITY OF NEW SOUTH WALES By FRASER OLD & SOHN Patent Attorneys for the Applicants