Amusement game devices, such as pinball machines, video games, redemption games, etc. of the commercial, e.g., revenue generating, and non-commercial, e.g., home entertainment, type are well known in the art. By way of example, U.S. Pat. No. 5,338,031, U.S. Pat. No. 6,158,737, and U.S. Published Application No. 2007/0026918 (which publications are incorporated herein by reference in their entirety) illustrate and describe amusement game devices of the type having a cabinet which houses a playfield assembly including a playing field or playfield which may be inclined. As further described in the '031 patent, it is known that players often attempt to lift, shake, shove, tilt, etc. such amusement game devices (individually and collectively referred to herein as “tilting” an amusement game device) for the purpose of influencing operation of the devices to their advantage. Thus, in order to prevent such abuse, amusement game device manufacturers have developed tilt prevention mechanisms that terminate play of the game, in whole or in part, if the amusement game device is tilted beyond predetermined limits. Conventionally utilized tilt prevention mechanisms include an electrically conductive member suspended from the game cabinet in pendulum fashion and an electrical contact surrounding the conductive member. When the game is tilted during game play the free end of the conductive member swings into the contact ring and completes a circuit directing the game's microprocessor to stop play as described above.
The following describes an improved tilt sensing system and method for an amusement game device, such as a pinball machine. Generally, operation of an amusement game device is controlled in part by using an accelerometer positioned with a game cabinet of the amusement game device. The accelerometer is first used to establish a reference idle position for the amusement game device. During game play of the amusement game device, it is then determined if a force applied to the amusement game device as sensed by the accelerometer exceeds a threshold that is set relative to the reference idle position for the amusement game device. When it is determined that a force applied to the amusement game device as sensed by the accelerometer during play of the amusement game device exceeds the threshold that is set relative to the reference idle position for the amusement game device, play of the amusement game device is caused to be inhibited in whole or in part.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the objects, advantages, features, properties and relationships of the tilt sensing mechanism for an amusement game device described hereinafter will be obtained from the following detailed description and accompanying drawings which set forth illustrative embodiments which are indicative of the various ways in which the principles of the invention may be employed.
For a better understanding of the amusement game device described hereinafter reference may be had to the following drawings in which:
FIG. 1 illustrates an exemplary amusement game device in the form of a prior art pinball machine; and
FIG. 2 is an exemplary block diagram of an amusement game device including accelerometer based tilt sensing functionality.
With reference to the Figures, an amusement game device, in the exemplary form of a pinball machine 10 is now described. It is to be appreciated, however, that this exemplary form for the amusement game device 10 is not intended to be limiting. Rather, those of ordinary skill in the art will appreciated that the tilt sensing mechanism described hereinafter can be utilized in any type of amusement game device, such as video games, redemption games, etc. of the commercial and non-commercial type, in which it is desired to inhibit a user's tilting of the amusement game device during play thereof.
In keeping with the example of an amusement game device 10 of the pinball machine type, the amusement game device 10 illustrated in FIG. 1 includes a cabinet 12 which houses various apparatus used to define play of a game. Game play may be commenced in response to insertion of money—paper or coins referred to collectively as “coins”—into a coin accepting device, upon exercising of credits earned, by accepting payment from an account, e.g., via use of a swipe card reading device, a bar code reading device, a near field communications device, etc., and/or by otherwise making game play active. Upon activation of the game in this manner, game play, in the case of a pinball machine, is defined upon an inclined playfield assembly 14 that supports a number of playfield accessories or devices. More particularly, in the case of a pinball machine, game play is generally defined through the use of a pair of flippers 18 to propel a ball relative to the playfield 14 and input devices/accessories associated with the playfield 14. The playfield 14 is usually inclined from the horizontal such that the ball tends to eventually roll back down the playfield 14 in the direction of the flippers 18. While not intended to be limiting, the playfield accessories or input devices 16 may include elements such as bumpers, ramps, and/or targets. The playfield 14 may be covered by a transparent or glass sheet cover 25 to permit viewing of the playfield 14. In addition to the foregoing, the playfield 14 includes a plunger element 32 which shoots the ball up an alley 34 onto the playfield 14. The playfield 14 may also include lighting elements 22 and/or other features as desired. Other player-activated input elements, typically in the form of push-buttons on the sides of the cabinet 12, are usually provided for controlling operation of the flippers 18. The amusement game 10 may also include a backbox 26 which is mounted to overlay a top rear portion of the cabinet 12 and which contains a game display 28, such as a dot matrix display, CRT, or the like. The backbox 26 may also support speakers associated with the game sound system. Within the backbox 26 may be located various of the electronic devices/circuits for controlling the operation of the playfield, the display, general illumination, and the sound system. Such electronic devices/circuits could also, in whole or in part, be carried within the game cabinet 12.
For sensing a tilting of the amusement game device 10, the amusement game device 10 is provided with an accelerometer 40. As shown in FIG. 2, the accelerometer 40 is coupled to the processing device 42 which processing device 42 is, in turn, coupled to game input devices 44, such as switches associated with the cabinet 12, playfield 14, etc., and game output devices 46, such as lights 22, flippers 18, display 28, etc. via one or more bus systems. A memory device 48, such as a RAM, ROM, or the like, stores instructions and data usable by the processing device 42 to control play of the game, the game output devices 44, and the game input devices 44 as necessary based upon signals provided by the game input devices 44 and/or the accelerometer 40. It is to be understood that this illustrated embodiment is not intended to be limiting and that other manners for arranging the devices illustrated in FIG. 2 to provide for control of play of the amusement game can be utilized as needed.
In an exemplary embodiment, a microelectromechanical system (MEMS) device is utilized as the accelerometer 40. As will be understood, a MEMS device is a very small mechanical device with an electronic interface. As will be further understood, a MEMS accelerometer device comprises a reference mass on a cantilever beam. Flexing of the beam in response to a tilting of the amusement game device 10 is measured by the MEMS accelerometer device and a signal indicative of the measured tilting is provided to the processing device 42 for processing in accordance with the appropriate instructions as stored on memory device 48. As described below, the signal indicative of the measured tilting of the amusement game device can be in the form of an interrupt signal that is generated when a measured tilting force applied to the amusement device 10 exceeds a predetermined threshold.
As will be appreciated, the use of an accelerometer 40 to detect tilting of the amusement device 10, e.g., to sense both inclination and impact, has many benefits when compared to the aforementioned plumb tilt mechanism that is conventionally utilized in amusement games. For example, a MEMS accelerometer device is much less costly when considered against the cost of the components required to construct a plumb tilt mechanism. A MEMS accelerometer device is also easier to setup and adjust when compared to a plumb tilt mechanism, e.g., with a MEMS accelerometer device no mechanical components need to be arranged and sensitivity can be adjusted in software rather than by physically adjusting the plumb bob relative to the conductive ring. Yet further, a MEMS accelerometer device provides a more consistent response when compared to a plumb tilt mechanism, e.g., because the devices can be adjusted in software multiple devices can be set to provide near identical responses (which is particularly useful for tournament play) whereas the mechanical plumb tilt mechanism has more room for adjustment/calibration errors. Still further, a MEMS accelerometer device can be auto-calibrated via use of software, e.g., the software can be used to determine which direction is straight down and using this information can provide for compensation even if the board carrying the MEMS accelerometer device is installed on an angle. In addition, a MEMS accelerometer device can be used to measure applied forces in any direction not just horizontally.
While accelerometers can be found with one, two or three axes of measurement, in a preferred embodiment a three-axis (x, y, and z) MEMS accelerometer is utilized as the three-axis accelerometer provides, in keeping with the advantages above-noted, easy auto-calibration and the ability to detect motion in any direction.
In keeping with this preferred embodiment, before the MEMS accelerometer device is used to sense tilting of the amusement game device 10 during operation of the amusement game device 10, a small amount of configuration is generally required to set operational parameters, such as the range of sensitivity. In this regard, the accelerometer 40 may be configured to generate an interrupt signal (for provision to the processing device 42) when a specified tilting threshold is exceeded, such as when the amusement game device receives an impact, is in sensed free-fall, etc. As will be understood, providing a signal in the form of an interrupt helps to reduce the amount of communication necessary with the processing device 42. While it is preferred that the accelerometer 40 perform such threshold evaluations (which would require that the accelerometer 40 be a component part of an integrated circuit having a processing device, be placed on a board carrying a processing device, etc.), it is contemplated that such threshold evaluations could be performed by the processing device 42 using signals having data indicative of any forces applied to the amusement game device as provided to the processing device 42 by the accelerometer 40.
To calibrate the amusement game device 10, the amusement game device 10 is placed into idle, i.e., a state in which the amusement game device 10 is at rest with no external forces acting upon the amusement game device 10 other than gravity. In this state, an acceleration of approximately 1 g straight down is measured by the accelerometer 40 due to gravity. The three axes of the amusement game device 10 can then be referenced to this measured reference (idle) position (the reference position being in effect the position of the plumb bob hanging at rest centered within the contact ring). As this calibration is to be done when the amusement game device 10 is idled, it is preferred that the calibration be operator controlled, i.e., that it be initiated via use of a secure menuing system (e.g., a menuing system which is accessed by unlocking and opening the amusement game machine) such as described in U.S. Pat. No. 7,967,681 which patent is incorporated herein by reference in its entirety.
Once the idle position is referenced in the amusement game device 10, it will be appreciated that the system can be used to determine if, for example, the amusement game device 10 is shoved horizontally. In this regard, any force horizontally applied to the amusement game device 10 can be measured as an acceleration in a plane which is roughly perpendicular to what was calibrated as straight down. In a first embodiment, an acceleration threshold would be set in this plane and any acceleration that exceeds the threshold would be treated as a tilt event and an interrupt signal would be generated as noted above. Preferably, the threshold can be operator adjusted in software via the secure menuing system, e.g., via a selection of a desired numeric threshold on a pre-defined sensitivity scale or range, which setup is simpler and more repeatable across plural machines as compared to adjusting the height of a mechanical plumb bob.
In a second embodiment, an algorithm could be employed to emulate the behavior of the plumb bob. This may help to maintain the feel of the mechanical tilt mechanism. A “virtual plumb bob” could be implemented as a pendulum in two axes. Forces in the plane perpendicular to straight down would add energy to or subtract energy from the accelerometer pendulum, depending on the direction of movement of the pendulum and the direction of the incident force. If the position of the “virtual plumb bob” exceeds a predetermined radius a tilt event is sensed and a corresponding interrupt signal can be sent to the processing device 42.
It will be additionally appreciated that beyond simply measuring force in the plane parallel to the ground a 3-axis accelerometer can accurately detect more subtle changes such as if the amusement game device is lifted off the ground. For example, if a game is being operated as part of a tournament the accelerometer device may be able to detect, e.g., by detecting a repositioning force being applied to the machine whereupon the repositioning of the machine remains unchanged over time, that someone applied a shim or otherwise raised the front legs of the amusement game device 10 to slow down the play of the amusement game device 10. In this manner the accelerometer 40 can serve as a deterrent to cheating in a tournament.
While a specific embodiment of the invention has been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangement disclosed is meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any equivalents thereof.