Electronic chessboard sensing technology

Abstract

A chess set includes a plurality of conductive chess pieces, a chessboard having a playing surface, and an electronic system. The electronic chess set includes a capacitive sensing system configured to detect a user's contact with any of the plurality of conductive chess pieces located on the playing surface and a resonant electromagnetic frequency identification system configured to scan the playing surface for information concerning an identification of each of the plurality of conductive chess pieces located on the playing surface. The electronic chess set includes a processor that identifies, using a combination of information provided by the capacitive sensing system and the information provided by the resonant electromagnetic frequency identification system, locations of all pieces remaining on the playing surface immediately following a move completed by the user.

Description

ELECTRONIC CHESSBOARD SENSING TECHNOLOGYBACKGROUND OF INVENTION1. Field of Invention

[0001] This invention relates generally to electronic game boards. More specifically, at least one embodiment, relates to an apparatus, system and method for electronic chessboard sensing technology.2. Discussion of Related Art

[0002] Conventional electronic chess systems and other tangible electronic game boards are known to employ sensing technology to maintain an awareness of the current state of the game. For example, electronic chess systems with capacitive touch sensing of pieces record and track gameplay and the movement of the chess pieces. In one approach, cap-touch sensing circuitry in the playing surface is used in combination with conductive material in the playing pieces. This type of system can detect when a chess piece is touched by the user. This type system can also detect when a chess piece is present in a square on the gameboard.

[0003] Despite the benefits provided by this type of sensing, capacitive sensing does have limitations. For example, in some circumstances, a system using capacitive sensing to track gameplay can introduce errors in move-tracking. These errors can often confuse users. One such problem occurs when a user accidentally and / or unknowingly touches the wrong piece. In one common scenario, a user picks up their piece with the intention of capturing an opponent’s piece selected from among multiple pieces that the user’s piece is in position to capture at that move. A system relying solely on capacitive sensing to track gameplay determines the opponent’s piece that was captured by detecting the opponent’s piece that was touched first. If the user accidentally brushes an opponent’s piece that is available to capture but not selected by the user, the system will misunderstand the intended move and incorrectly identify the available but unselected piece as being captured. That is, these systems can misidentify the location of specific pieces on the gameboard.

[0004] In addition, many prior systems including those employing capacitive sensing are unable to distinguish one piece-type from another. In these systems, a rook and a knight will appear the same to the capacitive touch system as one example. One immediate issue this presents occurs when the user arranges the pieces on the board at the start of the game. Here, capacitive sensing systems cannot recognize when the pieces are placed incorrectly. These prior systems also cannot detect an arbitrary set up of pieces. This can occur, for example,where a user is interested in practicing play with a series of moves that start from a known endgame position. In prior systems, the user is required to operate a user interface and manually input the piece locations for the start of the endgame.

[0005] Also, conventional capacitive touch systems require a calibration to establish the signal levels of capacitance correlated to an occupied square versus an unoccupied square. These calibration values are susceptible to drifting in response to changes in temperature or other environmental conditions. This can introduce error in piece detection.

[0006] Other prior systems employ electromagnetic resonating circuits for chess piece identification. In these systems, each piece contains a circuit which typically is made of inductor(s) and capacitor(s) with values of inductance and capacitance (an LC circuit) selected to provide a particular resonant frequency. These approaches employ vertical wound inductors. However, this construction has limited utility because it is unsuitable for use with a chess piece that includes a significant conductive area along the bottom of the piece.

[0007] In addition, prior approaches employing piece-recognition resonance technology operate with a noticeable delay between placement of a piece and recognition of the new location of the piece by the system. The delay occurs because, with resonance technology, the board must be fully scanned across all sixty-four squares and the frequency space employed by the system before piece-locations are determined. Another drawback of electronic chess boards that rely on resonant scanning is that they cannot distinguish between a user placing a piece and not releasing it, and a user placing and releasing a piece. That is, these systems may not realize when a player has let go of a chess piece. A chess move is not official until the piece is released. For example, a user may slide a piece through several squares before releasing it in the final “move” square. Alternatively, users may begin to make a move with a piece by placing the piece at a new location, maintain contact with the piece, and then reconsider and pull the piece back before they release it. While this does not constitute a move, some prior systems can erroneously determine that this is a completed move. In other prior systems, these moves will have a delay until they are officially considered as a completion of a piece-placement. In summary, the prior systems using piece-recognition resonance technology can be slow to identify a piece and erroneous regarding the identification of the piece. This can defeat the original objectives for including the technology in the chess set.SUMMARY OF INVENTION

[0008] Therefore, there is a need for an electronic chess set that includes a combination of piece selection and piece identification to increase the speed and accuracy in identifying moves and associated piece locations during gameplay. According to some embodiments, an electronic chess set includes both a capacitive sensing system and a resonant electromagnetic frequency identification system that are employed together to track game play. Applicant finds that a combination of capacitive touch and resonant frequency scanning are faster and more accurate than frequency scanning alone, and more accurate than capacitive scanning alone. The combination of these two different sensing technologies addresses the shortcomings of prior capacitive-sensing-only-systems while preserving the benefits provided by an electronic system that can detect user touch. These embodiments can greatly increase the speed at which the electronic system can accurately identify the types of pieces present at their current locations on the gameboard following the completion of a move.

[0009] According to various embodiments, an electronic chess set including both a capacitive sensing system and a resonant electromagnetic frequency identification system employs these two different sensing technologies in combination to provide previously unrealized advantage in the accuracy and speed of move recognition. The preceding is achieved regardless of the amount of time the piece is in contact with the user prior to a release of the piece at the new location on the playing surface.

[0010] Applicant has recognized the synergistic advantages provided when a combination of the capacitive sensing system and the resonant electromagnetic frequency identification system are employed together. That is, the embodiments described herein are advantageous relative to the use of either resonant electromagnetic frequency identification systems or capacitive sensing systems alone. For example, unlike resonant electromagnetic frequency identification systems alone, these embodiments do not demand a long dwell time (or “steady state” post piece -release) to confirm a completion of a move. These embodiments also do not get tricked by slow travel across a discrete location on the playing surface (that is, across a square) or hesitation and removal of a piece from a square before the location of the piece is established for the move, a problem with resonant electromagnetic frequency identification systems when used alone. As compared with a capacitive sensing system alone, the embodiments described herein do not confuse the location to which a piece is moved. In contrast, prior approaches using capacitive sensing alone can get confused regarding the location where a newly-moved piece is placed in situations in which a move involves piece-capture and / or when the user accidently causes a position shift or momentary contact with an unmoved piece when completing their move.

[0011] The embodiments described herein accurately confirm an identification of the piece that is placed at a new location. This is completed rapidly and at the proper time, that is, immediately after the piece that is moved to a new location is released by the user. According to some embodiments, a combination of information provided by the capacitive sensing system and the information provided by the resonant electromagnetic frequency identification system, allows locations of all pieces remaining on the playing surface within 200 milliseconds of a move being completed by the user. According to a further embodiment, locations of all pieces remaining on the playing surface is determined within 100 milliseconds of a move being completed by the user. According to various embodiments, operation (for example, interrogation (also referred to as scanning) of individual locations of the playing surface) by the resonant electromagnetic frequency identification system for piece identification after a move is complete is accelerated based on information provided by the capacitive sensing system because the capacitive sensing system operates quicker than the resonant system. For example, in some embodiments, a space that has a capacitive-touch event because of a move can be prioritized during the post move scanning of the locations on the playing surface performed by the resonant system. That is, the space(s) can be included in the first set of locations that are interrogated immediately post completion of a move.

[0012] Applicant has recognized that a successful user experience in electronic chess sets and any web-based game play requires a correct identification of completion of a move on the first attempt to identify that change of state. This is because the game of chess is played on a clock and because the players’ turns switch and a new timer immediately starts once a move is detected and declared as complete. Embodiments described herein provide a substantial improvement over prior systems because these embodiments combine the accuracy of piece ID with an ability to hold off on declaring that a move is complete until the player releases the newly moved piece. Applicant has recognized the hereto before unknown advantages provide with a system that can prioritize piece ID scans to those squares where a touch / release action is detected during a just completed move. These embodiments provide the fastest identification of the new location of pieces on the playing surface on the completion of a move. Further, embodiments can dwell in an interim state pending a completion of a move while the player remains in contact with a piece indefinitely. This operation is possible even in situations where a player slides a piece across multiple locations of the playing surface and withdraws a piece without releasing it. These substantialimprovements over prior approaches are achieved through the combined application of the capacitive sensing system and the information provided by the resonant electromagnetic frequency identification system.

[0013] In some embodiments, an electronic chess set employs both capacitive sensing and a resonant electromagnetic frequency identification system including conductive chess pieces including a planar resonant circuit oriented horizontally. That is, the circuit is oriented parallel to the playing surface of the gameboard with the piece placed upright at a location on the playing surface. In various embodiments, this construction allows effective utilization of both a resonant electromagnetic frequency identification system and a capacitive touchsensing system for an electronic chess set.

[0014] According to one aspect, a chess set includes a plurality of conductive chess pieces, a chessboard having a playing surface, and an electronic system. In various embodiments, the electronic system includes a capacitive sensing system configured to detect a user’s contact with any of the plurality of conductive chess pieces located on the playing surface. The electronic system also includes a resonant electromagnetic frequency identification system configured to scan the playing surface for information concerning an identification of each of the plurality of conductive chess pieces located on the playing surface. According to these embodiments, the electronic chess set includes a processor configured to identify, using a combination of information provided by the capacitive sensing system and the information provided by the resonant electromagnetic frequency identification system, locations of all pieces remaining on the playing surface within less than 200 milliseconds of a move completed by the user. According to these embodiments, a completion of the move is represented by a release of a chess piece by the user at a second location following a removal of the chess piece from a first location, the first location being different than the second location.

[0015] According to another aspect, a method of configuring a chess set, including a playing surface, to track locations of a plurality of chess pieces on the playing surface is provided. According to various embodiments, the method has acts of including in the chess set a touch-sensitive capacitive sensing system configured to detect when a user is in contact with a chess piece included in the plurality of chess pieces located on the playing surface, and including a resonant electromagnetic frequency identification system configured to identify a piece-type of each piece included in the plurality of chess pieces, respectively, when located on the playing surface.BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

[0017] FIG. 1 illustrates an electronic chess set in accordance with one embodiment;

[0018] FIG. 2 illustrates an exploded view of a chessboard according to one embodiment;

[0019] FIG. 3 illustrates a circuit included in the chessboard of FIG. 2 according to one embodiment;

[0020] FIG. 4 illustrates elements of a chess piece according to one embodiment;

[0021] FIG. 5 illustrates the elements of the chess piece of FIG. 2 assembled in accordance with one embodiment;

[0022] FIG. 6 illustrates a circuit board included in a chess piece in accordance with one embodiment;

[0023] FIG. 7 illustrates circuitry included in an electronic chess set in accordance with one embodiment; and

[0024] FIG. 8 illustrates a plot of waveforms 276 in accordance with one embodiment.DETAILED DESCRIPTION

[0025] This invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having,” “containing”, “involving”, and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0026] Referring now to FIG. 1, an electronic chess set 100 is illustrated in accordance with various embodiments. The chess set 100 includes a chessboard 102, a first plurality of chess pieces 104, and a second plurality of chess pieces 106. The chessboard 102 includes a playing surface 108 and a user interface 112. In the illustrated embodiment, the playing surface 108 includes a plurality of individually identifiable locations, for example, the locations 110 including light colored squares 113 and dark colored squares 114 configured in a checkerboard pattern. Depending on the embodiment, the playing surface 108 can include printed graphics, an illuminated grid, illuminated squares, a combination of any of thepreceding or any of the preceding in combination with other features used to define the plurality of individually identifiable locations in a manner visible to the user. In the illustrated embodiment, a subset of the plurality of individually identifiable locations 110 are illuminated squares, for example, the illuminated square 116.

[0027] As is described in detail below, embodiments of the chessboard 102 include a multilayer construction. According to some embodiments, the layers can be assembled together and supported by a rigid or semi-rigid case or frame. Depending on the embodiment, the case or frame can be a single piece or include multiple pieces. In an alternate embodiment, the layers include one or more flexible substrates secured together such that the entire chessboard can folded or rolled into a smaller form factor for storage or transport. In all the preceding embodiments, the chessboard 102 includes an integral electronic system as illustrated and described in detail herein. In various embodiments, the integral electronic system includes each of a touch-sensitive capacitive sensing system, a resonant electromagnetic frequency identification system and an illumination system.

[0028] In various embodiments, the plurality of chess pieces 104, 106 are designed with features that support an operation of the integral electronic system. For example, according to some embodiments, the plurality of chess pieces 104, 106 are conductive and include an integral coil. In these embodiments, a capacitive sensing system can detect a user’s contact with any of the plurality of chess pieces located 104, 106 located on the playing surface 108 while the resonant electromagnetic frequency identification system is configured to scan the playing surface for information concerning an identification of each of the plurality of chess pieces 104, 106 located on the playing surface 108. The integral electronic system can use a combination of information provided by the capacitive sensing system and the information provided by the resonant electromagnetic frequency identification system to rapidly locate and identify all pieces remaining on the playing surface 108 following a completion of a move. In addition, the illumination system can be used to identify, categorize and display available moves by illuminating locations 110 on the chessboard 102.

[0029] Regarding the touch sensitive capacitive system, embodiments of the electronic chess set 100 operate to detect capacitive properties of the plurality of chess pieces 104, 106 and display information about the game via the playing surface 108. The information displayed via the playing surface 108 can include the communication of moves to the user. In various embodiments, the moves are displayed in response to the human user’s selection of any one of the plurality of chess pieces 104, 106. The illumination locations 116 illustrated in FIG. 1 illustrate an example of a selection of the black bishop on the right of the image. Themoves that are displayed to the user can be selected for display based on the handicap-level desired for the user. That is, the handicap-level corresponding to a desired level of assistance for the user. To provide the user with an increased understanding of possible moves, a legend is employed with the chess set 100 to distinguish the strength of various moves. This is described in detail in commonly-owned U.S. Patent No. 11,893,900, entitled “Apparatus, System and Method for an Electronically Assisted Chessboard,” issued February 6, 2024. The disclosure of U.S. Patent No. 11,893,900 is herein incorporated by reference in its entirety.

[0030] As is described in greater detail below, the electronic chess set 100 includes elements of the resonant electromagnetic frequency identification system in both the chessboard and the individual chess pieces included in the plurality of chess pieces 104, 106. These include a coil associated with each of the individually identifiable locations 110, respectively. Each of the respective coils can be employed in both a transmit stage of a piece- ID operation and a receive stage of the piece-ID operation. Each of the plurality of chess pieces 104, 106 include a circuit with a coil and associated capacitor that resonate at a predefined frequency to provide information used to identify the piece.

[0031] In operation, the resonant electromagnetic frequency identification system alternates between transmitting and receiving. In some embodiments, a total of twelve different frequencies are employed to distinguish the twelve piece-types included in the plurality of chess pieces 104, 106. That is, there are twelve different values for the resonant LC circuit used in the plurality of chess pieces 104, 106, that is one for each of a king, a queen, a bishop, a knight, a rook, a pawn for both white and black. When the resonant electromagnetic frequency identification system is transmitting each of the twelve frequencies are separately transmitted at each of the 64 squares of the chess board. When the resonant electromagnetic frequency identification system is receiving, transmission is stopped and the system detects whether a piece is present on the square being interrogated as determined when a coil included in a chess piece at that location resonates in response to a particular transmit frequency. This occurs when the transmit frequency is set to the piece coils resonant frequency. If the coil is resonating it will couple energy back to the transmit / receive coil at that location on the playing surface 108. Operation of the resonant electromagnetic frequency identification system is described in greater detail below with reference to FIGS. 7 and 8.

[0032] Although the scanning process is described herein with reference to a sequential transmission of the twelve frequencies separately to each of the 64 squares of the chess board, other approaches can be employed in other embodiments. This can depend, for example, onthe capabilities and operating characteristics of the circuit elements employed in the transmission and reception of the interrogation and response signals, respectively. That is, the detailed approach described herein includes a multiplexed single receive system. However, in an alternative approach, entire ranks and / or files of squares on the playing surface can be sequenced through at the same time in embodiments in which multiple simultaneous receive channels are included. That is, for example, transmission of an interrogation signal on 8 rows in sequence 1 by 1 while always receiving on 8 columns. According to another embodiment, the electronic system generates a broadband pulse of all frequencies and distinguishes the frequency of the received signal that is returned. In yet another approach, chirp signals that sweep frequencies are employed.

[0033] Referring now to FIG. 2, an exploded view of an electronic chessboard 202 is illustrated in accordance with various embodiments. In general, the electronic chessboard 202 includes a layered construction to provide the sensing and illumination functions. In the illustrated embodiment, the electronic chessboard 202 includes a top graphic layer 220, an upper adhesive layer 222, a PCB layer 224, a lower adhesive layer 226, a top case 228, a mirror sheet layer 230 and a bottom case 232. The electronic chessboard 202 also includes a display module 234, an electronic circuit board 236, a battery 238 and a power switch 240.

[0034] The top graphic layer 220 includes the checkboard pattern that appears as the playing surface 108. In various embodiments, the top graphic layer 220 includes a substrate that includes one or more layers of ink or other medium printed on the substrate to form the checkerboard pattern. In a further embodiment, the multiple layers of ink include a first ink layer printed with white ink in a checkerboard pattern and a second ink layer printed with white ink in a pattern that matches a pattern of the solder mask that is included in the PCB layer 224. In various embodiments, the top graphic layer 220 can include one or more additional layers of printed ink including darker inks. In one embodiment, the top graphic layer 220 is manufactured from a thermoplastic polymer resin, for example, polyethylene terephthalate (PET).

[0035] According to the illustrated embodiment, the PCB layer 224 includes circuitry having an individual coil, capacitive touch sensing circuitry and a plurality of LEDs employed in the illumination system positioned to align with each of the plurality of individually identifiable locations 110, respectively, that are included in the electronic chess board 102, 202. According to some embodiments, each of the coils is capable of transmitting and receiving the resonant frequency ranges of the chess pieces as is described in greater detail herein. According to some embodiments, the capacitive touch sensing circuitryincludes a mutual capacitive sensing system. According to one of these embodiments, the capacitive sensing system includes 8 sensor drive lines and 8 sensor receive lines distributed on PCB layer 224 such that mutual capacitance of a drive line and a receive line is sensed at each of the 64 locations on the playing surface 108. In some embodiments, the resonating coil can also function as part of the capacitive touch sensing circuit. The plurality of LEDs are employed in the illumination system to illuminate the individual location at which the LEDs are included for the purpose of illuminating the location to provide a visual display to assist users in an identification and categorize of available moves.

[0036] In some embodiments, the PCB layer 224 includes a two layer printed circuit board (PCB). The top graphic layer 220 is adhered to the PCB to form a playing surface 208.Further, the LEDs included in the PCB layer 224 are aimed down in some embodiments with the light emitted by the LEDs reflecting off the mirror sheet layer 230 and back up and through a transmissive area of the associated location on the playing surface 208, see for example, the illuminated square 116 of FIG. 1. In various embodiments, areas of the PCB layer 224 that do not include circuit traces are left without solder mask and “white core” fiberglass of the PCB layer is used to allow light transmission through the PCB layer 224 to illuminate the playing surface 208.

[0037] According to the illustrated embodiment, the upper adhesive layer 222 is employed to secure a top side of the PCB layer 224 to an underside of the top graphic layer 220. The top side of the lower adhesive layer 226 is secured to the underside of the PCB layer 224. According to some embodiments, the top graphic layer 220, the upper adhesive layer 222, the PCB layer 224 and the lower adhesive layer 226 are provided as a subassembly for integration with the overall assembly that forms the electronic chessboard 202. According to these embodiments, the underside of the lower adhesive layer 226 is employed to secure the subassembly to the top case 228 during assembly.

[0038] According to the illustrated embodiment, the top case 228 includes an outer frame 242 and a grid region 244. The outer frame 242 provides four outer edge regions that define a central region of the frame 242. The grid subassembly 244 is located within the central region of the top case 228. According to an alternate embodiment, the top case 228 is assembled from two pieces with the grid region 244 provided by a subassembly that is secured within the central region of the outer frame 242. According to the illustrated embodiment, the grid subassembly 244 includes a total of sixty-four locations each one of which corresponds to one of the individually identifiable locations on the playing surface 208, respectively. In various embodiments, each of the outer frame 242 and the grid subassembly 244 aremanufactured from plastic although other materials may be employed depending on the embodiment. Further in the illustrated embodiment, the grid region 244 is painted white to assist in increasing the visibility of the illuminated squares.

[0039] The mirrored sheet layer 230 is located on an underside of the top case 228. In various embodiments, this is included to reflect light emitted from downward facing LEDs included in a lighting array to provide backlighting for illumination of the playing surface 208. For example, the lighting array is employed to illuminate the playing surface 208 with one or more available moves in a manner that also conveys the move-category (for example, a strength of a move). In some embodiments, the backlighting can also be employed to assist in defining the playing surface and / or operation of a user interface visible adjacent to the playing surface 208.

[0040] In the illustrated embodiment, the bottom case 232 forms an underside of the electronic chessboard 202. For example, the electronic chessboard 202 can be assembled by securing the top case 228 to the bottom case 232 to define an interior region. The mirrored sheet layer 230 can be located within the interior region with other elements of the chessboard 202 including, for example, the circuit board 236 and the battery 238. According to this embodiment, the chessboard 202 is formed with the subassembly including the top graphic layer 220, the upper adhesive layer 222, the PCB layer 224 and the lower adhesive layer 226 attached to the top case 228. The order of assembling the above-listed components can vary depending on the embodiment.

[0041] According to various embodiments, an electronic system included in the electronic chessboard 102, 202 includes the circuitry included in the PCB layer, the display module 234, the circuit board 236, the battery 238 and the switch 240. The electronic system will generally include one or more power busses and one or more communication busses. The communication busses can be used for the communication of instructions / commands and data between various components included in the electronic chessboard 102, 202 depending on the embodiment. The power busses can be used to distribute operating power at one or more voltage levels to the elements included in the electronic chessboard 102, 202.

[0042] In various embodiments, the display module 234 includes a touch screen display which is provided as the user interface 112. In one embodiment, the display module 234 employs LCD technology with in-plane switching (IPS) to provide a sharp image that can be seen from a wide variety of viewing angles. The user interface 112 allows the user to choose various play modes (including Al assisted with a selected level of assistance), pick their opponent (both Al and human via on-line chess communities) and track the play of eachplayer against the clock. The display can include digital graphics that illustrate the playing surface with locations of each of the plurality of chess pieces. The display can include an image representation of each piece including the color (black or white) and the specific piecetype (for example, a pawn, a knight, etc.). This allows the user to setup gameplay including end games for practice. According to one embodiment, the display module 234 including the user interface 112 is secured at a location on the upper surface of the top case 228. As illustrated in FIG. 2, the location is selected such that the user interface is directly accessible adjacent the playing surface 208. The power and communication busses connecting the display module 234 to the circuit board 236 can be included in a flex cable that is fed through an opening in the top case 228 for connection to the circuit board 236.

[0043] In various embodiments, the circuit board 236 includes a printed circuit board (PCB) with circuitry including a processor, memory, a wireless communication system, power circuitry and other elements. Depending on the embodiment, the processor can include one or more of a microcontroller, microprocessor or other processing element. According to one embodiment, the processor includes an integral BLUETOOTH low energy wireless communication system. According to another embodiment, the wireless communication system includes both a BLUETOOTH low energy wireless communication system and a WiFi communication system. In general, the processor executes stored instructions to control the overall operation of the chessboard, including operation of both the capacitive touch- sensitive system and the resonant electromagnetic frequency identification system along with operation of the lighting array to provide information to the user in response to receipt of a touch input or information concerning the identification of the chess pieces on the chessboard. The processor operates to perform other functions and operations depending on the embodiment. For example, the processor can operate to process various types of inputs, for example, commands, instructions or prompts received via the user interface 112 and / or from a user’s electronic device.

[0044] The circuit included in the circuit board also includes a memory configured to store software instructions in accordance with various embodiments. The software instructions can include one or more algorithms or other programs, for example, algorithms for determining a chess piece selected by the user, determining each of the moves available for a given state of a chess match, determining the move-strength and associated move-category of available moves, determining a location and piece-ID of all pieces on the chess board following completion of a move, determining a player’s selection of a game piece and displaying the moves available to the player for the selected game piece given the game-state. In oneembodiment, the memory is included in the processor. In another embodiment, the memory includes memory internal to the processor and memory external to the processor.

[0045] The circuit board 236 and the PCB layer 224 are connected to one another electrically to provide connections between the circuit board 236 and the capacitive touch- sensitive system, the resonant electromagnetic frequency identification system and the illumination system. According to one embodiment, the electrical connection between the PCB layer 224 and the circuit board 236 is completed with a board-to-board connection.

[0046] Depending on the embodiment, the battery 238 can include one or more batteries, for example, lithium or alkaline batteries. Further, the battery 238 can include a replaceable power source or a rechargeable power source depending on the embodiment. Where a rechargeable power source is employed, the circuit board 236 can include recharging circuitry to regulate charging operations. The recharging circuitry can include a wired electrical connection available from an exterior of the chessboard 202. According to the illustrated embodiment, the battery 238 is secured in an edge region within a cavity formed with the assembly of the top case 228 to the bottom case 232. The battery 238 is directly connected to the circuit board 236.

[0047] According to the illustrated embodiment, the switch 240 is externally accessible when secured in the housing formed with the assembly of the top case 228 to the bottom case 232. The switch 240 is connected to the circuit board 236. In various embodiments, operation of the switch 240 turns the electronic system on and off. For the user, this operation is apparent with the activation of the user interface included in the display module 234 when the switch is placed in the on position.

[0048] For each of the plurality of individually identifiable locations 110, respectively, that are included in the electronic chess board 102, 202, the PCB layer 224 includes circuitry for each of the capacitive touch-sensing system, the piece-ID resonant electromagnetic frequency identification system and the illumination system. Referring now to FIG. 3, a single square 245 from the PCB layer 224 at one of the individually identifiable locations 110 of the playing surface 108, 208 of the chessboard 102, 202 is illustrated. The square 245 has circuitry including a transmit / receive (Tx / Rx) coil 246, capacitive touch circuitry 248 and lighting circuitry including locations of contact pads 250 for a plurality of LEDs. Each square 245 of the PCB layer 224 also includes blank regions 252A, 252B, 252C and 252D.

[0049] The functionality required in each square 245 for piece ID sensing, capacitive touch circuitry and illumination results in competing design considerations concerning the area of the square 245 required for each. Further, the sensing circuitry must be configured andlocated within the square for operation even in cases where there is a misalignment in the piece positioning on the square 245. That is, the layout of the circuitry in each square 245 must account for some variance or imprecision in the placement of a chess piece on the square 245. As described further below, the design of the circuitry within each piece and the design of the piece-body can also be important design considerations to provide fast, reliable sensing. The embodiments described herein accomplish layout of a resonating coil and mutual capacitive touch sensor circuitry that provide robust sensing for piece-ID and capacitive touch detection while still retaining a large unoccupied area for light transmission at each location on the playing surface 108, 208. Routing for the LED system is also accommodated in the same playing area of the PCB layer 224.

[0050] The coil 246 included in these embodiments is newly added relative to prior approaches having sensing circuitry that only employed a capacitive touch-sensing system. In various embodiments, the coil 246 is capable of transmitting and receiving the resonant frequency ranges of the plurality of chess pieces 104, 106, based on interrogation signals emitted using a microcontroller located on the circuit board 236. As is described in greater detail below, the coil 246 is connected to the microcontroller and associated circuitry employed to emit the waveform that energizes the coil 246. The energized coil interrogates a square (one of the plurality of individually identifiable locations 110) at a known frequency before the signal transmission ends. Then the coil 246 becomes a receiver that listens to see whether a piece-coil is resonating in response to the interrogation. According to the illustrated embodiment, coil 246 is located at an outer edge of each square 245 of the PCB layer 224 corresponding to one of the plurality of individually identifiable locations 110 on the playing surface 108, 208.

[0051] In the illustrated embodiment, the capacitive touch circuitry 248 is in a geometric configuration that distributes the circuitry 248 in central regions of each square 245, along the four edges and radially inward from the outer edges toward the central region. The portion of the capacitive touch circuitry 248 in the central region of the square 245 includes an inner circular trace surrounded by an outer circular trace. A separate circuit trace is located parallel to and along each of the four outer edges. Each of these is connected to a circuit trace that extends radially inward from the circuit trace located on the edge. This circuit layout is employed to provide complete coverage for highly effective touch-sensing across the entire area of the square 245 while reducing the percentage of the area in which the circuit trace is located.

[0052] The layout of the coil 246 and the capacitive touch circuitry 248 divides each of the squares 245 into four quadrants, the blank regions 252A-252D. These blank regions 252A- 252D that do not include circuit traces are left without solder mask. This allows the “white core” fiberglass of the PCB layer 224 to be utilized for a transmission of light through the PCB layer 224 where it is visible at the playing surface 108, 208.

[0053] The circuit traces for connection of the plurality of LEDs (see corresponding contact pads 250) are located along the edges of the square 245. They are also adjacent the elements of the capacitive touch circuitry 248 that extend radially inward. This too contributes to the blank regions 252A-252D being free of any circuit traces. The use of a multilayer circuit board for the PCB layer 224 allows circuit elements to be located on opposite sides of the PCB. According to the illustrated embodiment, the LEDs are located on the underside of the square 245 and aimed downward. This allows the top side of the PCB to be dedicated to the circuit traces employed in the sensing systems. In various embodiments, RGB LEDs are employed to provide the capability to illuminate the square 245 with any of a wide variety of colors for a display of information to the user. For example, according to various embodiments, an LED body which includes a package of 3 LEDS attached to the PCB at the contact pad locations 250. In operation, the downward directed light emitted from the plurality of LEDs reflects upward off the mirror sheet layer 230 up through the transmissive area of the square 245 (that is, through the blank regions 252A-252D). This provides the illumination of the square 245 at which the plurality of LEDs are located, for example, as represented by the illuminated square 116 in FIG. 1 .

[0054] Referring now to FIG. 4, elements of a chess piece representative of the plurality of chess pieces 104, 106 are illustrated in accordance with various embodiments. That is, both FIG. 4 and FIG. 5 illustrate elements of a chess piece representative of individual chess pieces included in the plurality of chess pieces 104, 106. These elements include a conductive shell 253 having a body 254, a hollow interior region 255, an outer rim 256, a shelf 257 and a circuit board 258. The illustrated embodiment provides a conductive chess piece including a coil for piece-identification in a design that also maximizes a conductive area on an underside of the chess piece tailored for use with a touch- sensitive capacitive system. That is, the conductive area provided on the bottom of a chess piece constructed as illustrated in FIG. 4 compensates for the limited sensor circuit coverage in the playing surface as illustrated and described with reference to the square 245 in FIG. 3. As described herein, these embodiments employ the resonating circuit in a manner such that it doubles as a path for the capacitive sensing signal as well. This is accomplished by making the resonating circuit flat and densewith conductive traces over the entire circuit flat area. These embodiments effectively address the requirements of an electronic system that includes a combination of a resonant electromagnetic frequency identification system, a capacitive touch-sensing system and an illuminated playing surface on the chessboard.

[0055] Depending on the embodiment, the conductivity of the shell 253 can be achieved in any of a variety of ways. For example, the conductive shell 253 can be manufactured from a conductive material. This can include plastic with conductive material integrated in with the plastic from with which the conductive shell 253 is formed. According to another embodiment, the conductive shell is manufactured from a non-conductive material but includes a conductive exterior finish, for example a conductive paint, lacquer or other surface coating. In these embodiments, the conductive shell 253 provides a conductive surface for substantially all the surface of the conductive shell 253.

[0056] The body 254 is the area of the conductive shell 253 visible to the user when the chess piece is located on the playing surface 108, 208. When the users makes contact with the conductive shell 253, for example, to select a chess piece for a move, or a possible move, the user grips the body 254. The conductivity of the body 254 allows the capacitive touchsensing system to detect the user’s contact with the body 254 provided that the chess piece is located on the playing surface. The hollow interior region 255 is located within the body 254. This design reduces manufacturing costs by reducing the amount of material required to manufacture each piece. Further, such a design can also deliver a quality feel for the chess pieces provided that the wall thickness of the body 254 is great enough to provide the chess pieces with a mass and weight distribution typical of a solid chess piece.

[0057] The bottom of the conductive shell 253 includes an opening to the hollow interior region 255 with the opening defined by the outer rim 256 and the shelf 257. According to the illustrated embodiment, the outer rim 256 is included in a bottom surface of a fully assembled chess piece 104, 106. As compared with contact solely provided by the circuit board 258, Applicant finds that capacitive touch sensing is enhanced when the conductive shell 253 is also located on the bottom of the chess piece because it places at least a portion of the body on or immediately adjacent the playing surface 108, 208. Because the outer rim 256 forms a portion of the underside of the chess piece, the embodiment illustrated in FIG. 4 places that portion of the conductive shell 253 adjacent the playing surface 108, 208.

[0058] The shelf 257 is also formed in an underside of the conductive shell 253 immediately adjacent and radially inward of the outer rim 256. According to the illustrated embodiment, this configuration provides a recessed area in which the circuit board 258 isreceived, for example, as illustrated in FIG. 5. As described in greater detail in FIG. 6, the circuit board provides a coil having an overall planar construction. Applicant finds that the use of a planar circuit board for the coil included in each piece (a “piece-coil”) is beneficial because it provides a stable bottom surface for the chess piece that places the piece-coil closest to the PCB layer 224. The conductive nature of the coil also allows the circuit board 258 to provide a conductive surface area that is employed in the capacitive touch-sensing system. The recessed position of the shelf 257 relative to the outer rim 256 results in a combination of the outer rim and the circuit board 258 providing the flat bottom surface of the chess piece with the circuit board 258 placed against the shelf 257. According to some embodiments, a fully assembled chess piece (for example, the plurality of chess pieces 104, 106) includes felt adhered to the bottom to cover the circuit board and at least a portion of the outer rim 256.

[0059] Referring now to FIG. 6, further details of the circuit board 258 are illustrated. As mentioned above, embodiments include chess pieces featuring a flat PCB. The circuit board258 includes a coil 259. According to the illustrated embodiment, the coil 259 is a spiral copper coil that occupies most of the area of the circuit board 258. According to one embodiment, the coil 259 occupies a region of the circuit board 258 from the central axis of the PCB to adjacent an outer edge of the circuit board 258. In some embodiments, the coil259 is located on both sides of the circuit board 258. In other embodiments the coil is only located on a single side of the circuit board 258. The circuit board 258 also includes a capacitor circuit 260. In these embodiments, the coil 259 in combination with the capacitor circuit 260 form an inductor plus capacitor circuit (referred to as a “resonant circuit” or alternatively as an “LC circuit”). The resonant circuit, through selection of a capacitance value of the capacitor circuit 260 and an inductance value of the coil 259, resonates electromagnetic energy at a desired frequency (referred to as a “tone”). Greater inductance is beneficial to the efficiency in which the resonant circuit collects and emits energy.Embodiments described herein are configured to provide large inductance values relative to a given surface area, for example, the surface area available on the underside of a chess piece or for a given square. Higher inductance values can be achieved by increasing the number of turns in the coil. Inductance can also be increased by including the inductor over a larger percentage of the surface area of the PCB. In addition, Applicant finds that providing a relatively large inductor covering a significant amount of the area of the PCB also benefits the capacitive touch sensing system. According to the illustrated embodiment, the large spiral coil is designed to be part of the conductive area of each chess piece that interacts with theplaying surface’s sensor circuit. A portion of the coil 259 also overlaps with the chess piece’s shell material, further carrying the capacitive touch sensing throughout the piece body and surface. In contrast to alternate approaches, embodiments employing the resonant circuit as part of the capacitive sensing circuit reduces the number of components and a volume of material required for each chess piece, while also preserving all the functionality and benefits of a combination of touch sensing and resonant sensing for piece identification.

[0060] In operation, the resonant electromagnetic frequency identification system for piece identification includes elements of the electronic system that transmit the interrogation signal to the squares 245 and receive and process any signals returned in response. Referring now to FIG. 7, a circuit 262 for piece identification is illustrated in accordance with one embodiment. The circuit 262 includes a microcontroller 264, an amplifier circuit 266, a peak detector circuit 268, an analog-to-digital converter (ADC) 270, and a transmi t / receive coil 272. FIG. 7 also illustrates a separate resonant circuit 274 included in one of the plurality of chess pieces 104, 106, with the chess piece located at a location on the playing surface corresponding to the location of the square 245 in which the transmit / receive coil 272 is located. Where the playing surface includes sixty-four locations, the microcontroller 264 can be coupled to the respective transmit / receive coils at all sixty-four locations on the chessboard as is explained in greater detail below.

[0061] In the circuit 262, the output of the microcontroller 264 is connected to the transmit / receive coil 272. The transmit / receive coil 272 is also connected to an input of the amplifier circuit 266. The output of the amplifier circuit 266 is connected to an input of the peak detector circuit 268. The output of the peak detector circuit 268 is connected to an input of the ADC 270.

[0062] In the illustrated embodiment, the microcontroller 264 operates to generate and transmit a signal employed to interrogate locations on the playing surface 108, 208. As is described here, the signal is transmitted to, for example, the squares 245 where one of the plurality of chess pieces 104, 106 may be located during gameplay. In various embodiments, the signal is emitted at a selected frequency that resonates the resonant circuit 274 if the frequency of the signal is set to the resonant frequency of the resonant circuit 274 included in a chess piece located at an individually identifiable location on the playing surface. According to some embodiments, the signal emitted by the microcontroller 264 is a square wave. Because the playing surface includes sixty-four individually identifiable locations, a set of multiplexers are employed to select the location (and corresponding transmit / receive coil 272) to which the signal is transmitted at any one time. Further, the microcontroller 264operates the transmit circuitry to cycle through each of the different frequencies used to distinguish the plurality of chess pieces 104, 106 from one another. According to one embodiment, a total of twelve different frequency square waves are employed to distinguish the twelve piece-types included in the plurality of chess pieces 104, 106.

[0063] Referring to FIGS. 2 and 3, a separate transmit / receive coil 272 is included in each of the squares 245 located on the PCB layer 224. In a receiving mode, the microcontroller 264 stops transmission of the interrogation signal and the system listens to detect whether a piece is present on the square being interrogated as determined when the resonant circuit 274 of a chess piece at that location resonates in response to a particular transmit frequency. If the resonant circuit 274 is resonating it will couple energy back to the transmit / receive coil 272 at that location on the playing surface 108, 208.

[0064] The coupled signal has a relatively small amplitude produced when the resonant circuit resonates. However, the amplifier circuit 266 is used to amplify the coupled signal. The amplified signal is provided to the input of the peak detector circuit 268. The peak detector circuit 268 holds a voltage at the peak voltage level of the amplified signal. This operation is repeated for each of the coupled signals received when a location (the square 245) is interrogated at each of the separate frequencies.

[0065] The peak voltage level is received at the input of the ADC 270. The ADC 270 measures the voltage level received from the piece in response to each of the separate frequencies with which the location is interrogated. The frequency of the interrogation signal that produces a response that has the highest peak voltage corresponds to the piece-type that is located at the square 245 that is being interrogated. According to embodiments, the ADC 270 is included in a microcontroller. According to one embodiment, the ADC 270 is included in the microcontroller 264. In another embodiment, the ADC 270 is included in a separate microcontroller.

[0066] Referring now to FIG. 8, a plot of waveforms 276 are illustrated in accordance with various embodiments. The plot 276 include a first set of waveforms 278, a second set of waveforms 280 and a third set of waveforms 282. Each of the three sets of waveforms 278, 280, 282 show an interrogation signal, a response signal received from the coupled energy of the resonant circuit included in a single chess piece located at a location on the playing surface resulting from the interrogation signal and a peak-detector output signal. For clarity, only three sets of waveforms are illustrated in FIG. 7. Each set of waveforms 278, 280, 282 represents an interrogation and response by a selected one of the twelve piece-types to an interrogation at a single frequency. In practice, however, a set of waveforms exist for each ofthe frequencies at which the individual transmit / receive coils 272 are interrogated. For example, where twelve frequencies are employed corresponding to the twelve piece-types in a chess set, a total of twelve sets of waveforms will result where each of the twelve sets include an interrogation signal at the selected frequency, a corresponding response signal and a peak-detector output signal. That is, the interrogation can be performed at each frequency at which a piece-type may resonate.

[0067] Each of the sets of waveforms includes a period during which the interrogation signal is being transmitted to the left of the vertical line. Each set also includes a period during which the transmission is stopped and the response signal is received to the right of the vertical line. The waveform that appears in a dashed line illustrates the peak detector output signal.

[0068] The first set of waveforms 278 illustrates a square waveform at a first frequency used to interrogate a location on the playing surface 108, 208. The peak detector signal for the resonant response signal has a value of 0.865 Volts. The second set of waveforms 280 illustrates a square waveform at a second frequency used to interrogate the location on the playing surface 108, 208. The peak detector signal for the resonant response signal for the second frequency has a value of 2.7 Volts. The third set of waveforms 282 illustrates a square waveform at a third frequency used to interrogate the location on the playing surface 108, 208. The peak detector signal for the resonant response signal for the third frequency has a value of 0.953 Volts.

[0069] The sets of waveforms presented in FIG. 8 are an example of an interrogation of three pieces that are set to resonate at three different frequencies that are close enough to one another that the piece-coil resonates for all three. In this case, the system selects the piecetype associated where the peak response is greatest. In this example, the peak detector value of the response signal almost three times greater at the second interrogation frequency than that found in response to the third interrogation frequency and more than three time greater than that found in response to the first interrogation signal. This provides the system with information that allows it to identify the piece-type at the location based on a piece-type associated with the second frequency.

[0070] Where capacitive sensing is employed, the change in capacitance (for example, a change in the mutual capacitance or inverse thereof) is sensed by the touch sensitive system 234 when a user makes contact by touching a selected one of the chess pieces 104, 106. The processor 232 employs the information concerning the change in capacitance to determine a location on the playing surface 109 where the selected chess piece is located. With thisinformation the processor identifies the set of moves that are currently available for the selected chess piece.

[0071] Applicant recognizes that the sensing capabilities of the touch sensitive capacitive system can be combined with the capabilities of the resonant frequency piece ID system to speed the scanning operation by reducing the number of individually identifiable locations 110 (the squares 245) that must be scanned to maintain a current awareness of piece locations on the chessboard 102, 202. According to some of these embodiments, the system prioritizes piece ID scans to those squares where a touch / release action is detected during a just completed move. These embodiments provide the fastest identification of the new location of pieces on the playing surface on the completion of a move.

[0072] While shown and described with reference to resonant frequency piece ID systems in combination with touch sensitive capacitive systems, embodiments can include alternatives to resonant frequency piece ID systems. These alternatives can also include sensing based on inductive coupling. For example, according to one embodiment, RFID is employed as an alternative to resonant frequency piece ID. According to another embodiment, NFC is employed as an alternative to resonant frequency piece ID. According to each of these embodiments, a multiplexed system can scan the gameboard at selected frequencies by activating coils to provide energy to chess pieces that are located the squares of the playing surface. Either of these embodiments can be employed in combination with touch sensitive capacitive systems to provide all or some of the advantages described above with reference to electronic chess sets that include resonant frequency piece ID systems in combination with touch sensitive capacitive systems.

[0073] While shown and described with reference to a chess set, embodiments described herein can also be employed to assist a user to increase their level of skill and enjoyment of different games that use different games pieces. These can include board games like Go, Draughts and Checkers as some examples.

[0074] Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are by way of example only.

Claims

WHAT IS CLAIMED IS:

1. A chess set, comprising: a plurality of chess pieces; a chessboard having a playing surface including a plurality of individually identifiable locations visible to a user on the chessboard; and an electronic system including: a touch-sensitive capacitive sensing system configured to detect when a user is in contact with a chess piece included in the plurality of chess pieces located at one of plurality of individually identifiable locations; and a resonant electromagnetic frequency identification system configured to identify a piece-type of each piece included in the plurality of chess pieces, respectively, when located at a location included in the plurality of individually identifiable locations.

2. The chess set of claim 1, wherein each of the plurality of chess pieces is conductive.

3. The chess set of claim 1, wherein each of the plurality of chess pieces includes a resonant circuit, respectively.

4. The chess set of claim 3, wherein each of the respective resonant circuits includes an overall planar construction.

5. The chess set of claim 1, wherein each of the plurality of chess pieces is a conductive chess piece, respectively, that also includes a planar resonant circuit employed in coupling the chess piece with the resonant electromagnetic frequency identification system, and wherein the planar resonant circuit is also employed as a conductive path employed in the touch-sensitive capacitive sensing system.

6. The chess set of claim 5, wherein each of the plurality of individually identifiable locations includes a coil included in the resonant electromagnetic frequencyidentification system, the coil configured to inductively couple to the planar resonant circuit included the respective chess piece when located at the location included in the plurality of individually identifiable locations.

7. The chess set of claim 6, wherein the electronic system includes an illumination system, and wherein each of the plurality of individually identifiable locations includes at least one LED, respectively, included in the illumination system, the respective at least one LED configured to illuminate at least a region of the location included in the plurality of individually identifiable locations at which the respective at least one LED is located.

8. The chess set of claim 7, wherein the chessboard further includes a reflective surface located beneath the playing surface, and wherein each of the plurality of individually identifiable locations includes a blank region for a transmission of light produced by the respective at least one LED at the respective location after the light is reflected from the reflective surface.

9. The chess set of claim 1, wherein the electronic system includes an illumination system, wherein each of the plurality of individually identifiable locations includes at least one LED, respectively, included in the illumination system, the respective at least one LED configured to illuminate at least a region of the location included in the plurality of individually identifiable locations at which the respective at least one LED is located, wherein the chessboard further includes a reflective surface located beneath the playing surface, and wherein each of the plurality of individually identifiable locations includes a blank region for a transmission of light produced by the respective at least one LED at the respective location after the light is reflected from the reflective surface.

10. A method of configuring a chess set including a playing surface to track locations of a plurality of chess pieces on the playing surface, the method comprising: including in the chess set a touch-sensitive capacitive sensing system configured to detect when a user is in contact with a chess piece included in the plurality of chess pieces located on the playing surface; anda resonant electromagnetic frequency identification system configured to identify a piece-type of each piece included in the plurality of chess pieces, respectively, when located on the playing surface.

11. The method of claim 10, further comprising employing the touch-sensitive capacitive sensing system to determine a removal of a chess piece included in the plurality of chess pieces, by a user, from a first location on the playing surface and a placement, by the user, at a second location on the playing surface, the placement confirmed with a release of the chess piece by the user at the second location as detected by the touch-sensitive capacitive sensing system.

12. The method of claim 11 , further comprising confirming the release within less than 200 milliseconds of the release by the user with the chess piece at the second location.

13. The method of claim 12, further comprising employing a combination of the touch-sensitive capacitive sensing system and scanning performed by the resonant electromagnetic frequency identification system to maintain an identification of a current location of all pieces remaining on the playing surface within less than 200 milliseconds of a move completed by the user as represented by the release.

14. The method of claim 13, wherein the playing surface includes sixty-four individually-identifiable locations at which chess pieces included in the plurality of chess pieces can be located.

15. The method of claim 11 , further comprising: employing a combination of the touch-sensitive capacitive sensing system and scanning performed by the resonant electromagnetic frequency identification system to maintain an identification of a current location of all pieces remaining on the playing surface following the release of the chess piece by the user; and employing information provided by the touch-sensitive capacitive sensing system to prioritize a scanning of at least one of the first location on the playing surface and the second location on the playing surface by the resonant electromagnetic frequency identification system following the release of the chess piece by the user.

16. A chess set, comprising: a plurality of conductive chess pieces; a chessboard having a playing surface; and an electronic system including: a capacitive sensing system configured to detect a user’s contact with any of the plurality of conductive chess pieces located on the playing surface; a resonant electromagnetic frequency identification system configured to scan the playing surface for information concerning an identification of each of the plurality of conductive chess pieces located on the playing surface; and a processor configured to identify, using a combination of information provided by the capacitive sensing system and the information provided by the resonant electromagnetic frequency identification system, locations of all pieces remaining on the playing surface following a release of a chess piece by the user on a completion of the move, the completion of the move represented by the release of the chess piece at a second location following a removal of the chess piece from a first location, the first location being different than the second location.

17. The chess set of claim 16, wherein the electronic system is configured such that the identification of the locations of all pieces remaining on the playing surface occurs within less than 200 milliseconds of the move being completed by the user,

Images