Weighing apparatus in a gaming, amusement, or vending machine

Abstract: An apparatus and method are provided for deterring gaming machine theft and fraud by weighing the number of coins accumulated in a gaming machine hopper assembly ( 9 ). In one preferred embodiment, a coin weighing apparatus ( 12 ) consisting of a load cell ( 13 ) and internal strain gauge ( 18 ) is constructed integrally with the coin hopper assembly and fits between the coin hopper ( 10 ) and its base plate ( 14 ). In other preferred embodiments, the coin weighing apparatus ( 22 , 43 , 50 ) is constructed separately from the coin hopper assembly. In these other preferred embodiments, the weighing apparatus includes upper ( 24 , 46 , 52 ) and lower plates ( 26 , 48 , 60 ) which are separated by one or more load cell weighing instruments ( 28 , 45 , 56 ). In operation, the lower plate of this stand-alone weighing apparatus is typically placed against the bottom ( 8 ) of the slot machine and the hopper is then simply placed on top of the weighing apparatus' upper plate. The present invention also provides a method of detecting fraud or theft using the weighing apparatus of the present invention to take periodic readings of the number of coins residing in the hopper and communicating those readings as appropriate.

Description: The present invention relates to a weighing apparatus in a gaming, vending or amusement machine and to a method of coin theft detection in a gaming, amusement or vending machine comprising such a weighing apparatus. This kind of machines comprises coin hoppers which are used to collect and distribute coins in gaming, amusement and vending machines, were it is usual to determine the number of coins in a hopper by weighing the hopper and using the collected hopper weight information to deter fraud and theft. BACKGROUND OF THE INVENTION For many years, slot machines have been a popular attraction at gambling casinos and other gaming establishments. Such slot machines typically have a colorful display of gaming indicia, such as cherries, plums, oranges, sevens, etc. arrayed in rows and columns across the front of the slot machine. These gaming indicia can be spun into motion for game play by the insertion of a coin into the slot machine and pulling the slot machine handle. During game play, the inserted coin is collected in a coin reservoir within the slot machine called a "hopper". At the end of game play, the inserted coin will be retained in the hopper if there is a losing combination of gaming indicia shown or, alternatively, may be returned from the hopper to the slot machine player, perhaps with additional coins, if there is a winning combination of gaming indicia shown. Periodically, slot machine hoppers must be serviced by casino technicians. For example, the hopper may have too few or too many coins and must have its contents adjusted appropriately. Also, coins might be jammed in parts of the hopper in such a way that the hopper cannot function properly. If so inclined, a dishonest technician can pilfer a few coins each time he services a slot machine. While each individual instance of such pilfering may not represent a significant threat to a casino's bottom line, the cumulative loss over time from such pilfering can be quite large. Casinos have tried to combat this problem by, among other things, assigning two or more technicians to each task requiring a slot machine to be opened. However, this approach leads to additional labor costs and may not even help if each of the assigned technicians is dishonest. An alternate existing solution is to seal the hopper so that only trusted money-handling employees working in a cashier's cage can get to the coins. Nonetheless, slot machine hoppers are difficult to seal because such hoppers must typically give out coins after a winning play as well as receive them. Having coins jam is the hopper is also an ongoing concern. In those cases where the hopper is prone to jamming, sealing the hopper would inevitably result in greater down-time for the slot machines and create a loss of slot machine use which could be more detrimental to the casino than the theft loss. Coins can be pilfered from slot machines hoppers not only by casino technicians but also by the slot machine players. For example, a player might attach a string to the coin he is inserting into the slot machine so that he can retrieve the coin from the slot machine by simply pulling the string after the coin has been erroneously counted as "received" by the slot machine and game play has begun. Also, the player might try to jam the payout counter after receiving a winning combination so that the slot machine continues Unfortunately, merely counting passing coins as they go into the hopper and counting passing coins as they leave the hopper would not solve these types of theft problems. In the case of player fraud, the player can effectively fool or otherwise disable the existing types of coin counters. Similarly, in the case of technician fraud, such a physical inventory would only indicate that coins are missing, not who took them. Prior art systems exist to count coins by weighing them. For example, U.S. Patent No. 5,193,629 and U.S. Patent No. 4,512,428 describe apparatuses for weighing coins. Nonetheless, while such weighing devices might be suitable for weighing coins in a money room, they are unsuitable for weighing coins in a vibration-prone gaming machine environment where the hoppers being weighed must be enclosed to prevent theft by players. In Figure 2 of GB-A-2 221 315 the long dimension of load cell 8 is indicated to be arranged parallel to the axis of hopper 15. SUMMARY OF THE INVENTION The present invention provides a weighing apparatus in a gaming, amusement or vending machine of claim 1. Prefered embodiments are defined by claims 2 and 3. The weighing apparatus may be constructed integrally with the coin hopper assembly and fits between the coin hopper and its base plate. In other preferred embodiments, the weighing apparatus is constructed separately from the coin hopper assembly. In these other preferred embodiments, the weighing apparatus includes upper and lower plates which are separated by one or more weighing instruments, such as load cells with strain gauges. In operation, the lower plate of this weighing apparatus is typically placed against the floor of the slot machine and the hopper is then simply placed on top of the weighing apparatus' upper plate. The present invention also provides a method of coin theft detection of claim 4 comprising the weighing apparatus of claim 1. Preferred embodiments are defined by claims 5 to 14. The weighing apparatus may take periodic readings of the number of coins residing in the hopper and can communicate those readings. Using a preferred method of the present invention, the unauthorized removal of coins during an actual or purported technician maintenance procedure can be detected by determining a count of coins by weight when the slot machine door is opened, determining a count of coins by weight once the slot machine door is closed, and using those two counts to determine the change in the number of coins in the hopper at the time of servicing. The identity of the person opening the hopper door and the time at which the hopper door is opened and closed can be recorded, along with any detected discrepancy. The calculation of any detected discrepancy may take into account an expected change in coin count. An expected change in coin count would exist when a technician is asked to open the machine and either remove or insert coins. A similar method can also be used to detect a player's theft of coins from the slot machine. In this method, the actual number of coins in the hopper can be determined by weight and compared with the expected number of coins in the hopper in order to determine if the player has inappropriately been withholding or taking coins from the slot machine. If any unexpected coin discrepancy is detected by the weighing apparatus of the present invention, it can be communicated to appropriate security personnel in real time through a computer hook-up or alarm or, alternatively, communicated periodically through downloading of stored hopper weight information. A further understanding of the nature and advantages of the present inventions may be realized by reference to the remaining portions of the specification and the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a slot machine with its door open showing a coin hopper and integrated weighing apparatus of the present invention. FIG. 2 is a more detailed side view of the coin hopper shown in FIG. 1 illustrating the cantilevered mounting of the integrated weighing apparatus of the present invention onto the coin hopper, load cells. FIG. 3 is a schematic diagram of the accompanying electronics for the weighing apparatuses shown in FIGS. 1-2. FIG. 4 is a flowchart of an accounting process for to detect coin hopper theft in a timely manner. FIG. 5 is a flowchart of a process for automatically taking periodic measurements to determine a coin count in the hopper. FIG. 6 is a flowchart of a process for calibrating a hopper's tare weight and a per coin weight. FIG. 7 is a flowchart of a process for obtaining an accurate hopper weight during calibration in the presence of noise and/or vibrations. FIG. 8 is a flowchart of a process for obtaining an accurate coin count in the presence of noise and/or vibrations. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a coin hopper assembly 9 in a slot machine 1 which incorporate an integrated form of coin weighing apparatus 12 of the present invention. This coin hopper assembly 9 includes a coin hopper 10 , hopper base plate 14 and integrated coin weighing apparatus 12 . To show the placement of the hopper assembly 9 in the slot machine 1 , the hopper door 2 of slot machine 1 is shown in an open position. Nonetheless, during operation, the hopper door 2 would usually be locked shut to prevent theft of coins. As shown here, coin hopper 10 is often placed below a coin insertion slot 3 and above a coil payout tray 4 . To initiate play of a game, a player would insert one or more coins into coin insertion slot 3 and those coins would drop into coin hopper 10. Although not shown in FIG. 1 , the coins would typically pass through a coin handling unit on their way to coin hopper 10 . This coin handling unit performs tests (size, weight, angular momentum, etc.) to determine if the coin is real and of the proper denomination. The coin handling unit, or other device, would provide a signal, such as an electric "coin in" pulse, to a logic board to indicate that a valid coin has been inserted (See, FIG . 9) . If the game is a winning game, or the player cashes out his or her credits, coin hopper 10 ejects the correct amount of coins from ejection slot 5 into payout tray 4 . In some embodiments, such as so-called "slant-top" slot machines, the hopper 10 is actually located below the payout tray and an "elevator" or "escalator" mechanism is used to raise the paid out coins higher than the payout tray so that the coins will fall into the payout tray, and thus be accessible to the player. Typically, a motorized conveyor assembly (not shown) of coin hopper 10 causes coins to be ejected to the payout tray or elevator and that conveyor assembly runs until a "coin out" counter indicates that the correct number of coins have been ejected. FIG. 2 provides a close-up view of how the integrated form of coin weighing apparatus 12 of FIG. 1 is mounted in the coin hopper assembly 9. In this preferred embodiment, the coin weighing apparatus 12 includes a load cell 13 and strain gauge 18 . This coin weighing apparatus 12 is mounted between the coin hopper 10 and hopper base plate 14 . The coin weighing apparatus 12 is affixed to the coin hopper 10 by a cantilevered spacer 16(a) and an appropriate fastener 17 . At its diagonally opposite end, the coin weighing apparatus 12 is also affixed to the hopper base plate 14 by a cantilevered spacer 16(b) and an appropriate fastener (not shown). In this arrangement, coin hopper 10 is totally supported by cantilever spacer 16(a), which is in turn totally supported by coin weighing apparatus 12 , which is turn totally supported by cantilever spacer 16(b) mounted directly to base 14 . Thus, the weight of the coin hopper 10 and its coins is applied to the load cell 13 of the coin weighing apparatus 12 causing a strain on the load cell 13 which is a function of the weight of the coin hopper 10 and its coins. That strain is measured by a strain gauge 18 and electrically conveyed to a suitable electronic monitoring apparatus (not shown) by the lines of cabling 20 . In this preferred embodiment, load cell 12 might suitably be a Model 1040 digital load cell or Model 1041 analog load cell manufactured by Tedea Huntleigh of Canoga Park, California. Alternatively, the load cell 12 might suitably be a 36-kilogram analog load cell sold by HBM, Inc. of Connecticut with a Cirrus Logic strain gauge sensor. For larger coin hoppers 12 , a 72-kilogram analog load cell sold by HBM, Inc. might be used. Compression, sub-miniature and strip sensor types of load cells may suitably be used with the weighing apparatus of the present invention. The coin weighing apparatus 12 shown in FIGS. 1 and 2 is referred to as "integrated" into the coin hopper assembly 9 because it is situated between the coin hopper 10 and hopper base plate 14 . For existing slot machines, installation of this integrated form of coin weighing apparatus 12 typically involves removing the coin hopper assembly 9 from the slot machine 1 and separating the coin hopper 10 from the hopper base plate 14. The coin weighing apparatus 12 can then be integrated into the coin hopper assembly 9 by affixing it to the coin hopper 10 and hopper base plate 14 as shown in FIG. 2 . Referring now to FIG. 3 , a schematic of a preferred logic board 100 used in the present invention is shown. In an alternative embodiment, the role of the logic board is subsumed into a central slot machine control system. The logic board comprises an analog-to-digital converter 102 (A/D) coupled to load cell 13 to convert a load signal from an analog signal to a digital load cell sample. In the preferred embodiment, the digital load cell sample has a resolution of 20 bits, but other resolution analog-to-digital converters can also be used (e.g., 14 bits or greater). With a lower resolution 14 bit digital load cell, an integer corresponding to the digital load cell sample can range from 0 to 16,383. With proper calibration and proper selection of load cell 13 , a fully loaded hopper will cause a reading near the top end of the range, so as to have the best resolution. A/D 102 provides its output to an input-output (I/O) controller 104 which in turn provides samples, as requested, to a central processing unit (CPU) 106. A suitable I/O controller for the present invention would be a 75HCT245 chip. CPU 106 executes programs stored in program memory 108 and uses a variable memory 110 to store data incident to the execution of those programs. The programs executed by CPU 106 comprise instructions for following the processes described in FIGS. 4-8 , however CPU 106 might also execute other programs not described herein. In some embodiments, a CPU with built-in I/O control functions and/or memory might be used, however the description of FIG. 3 still applies to such integrated systems. FIG. 3 shows a number of I/O signals being provided to, or by, I/O controller 104 . For example, "Coin In" and "Coin Out" signals are provided from coin handling devices. These signals can be pulses (one pulse per coin) or can be other signals indicating a count, as are well known in the art. I/O controller 104 might also provide motor, sound, reel, lights and display control signals, if CPU 106 or I/O controller 104 are programmed to handle such functions of slot machine 1. I/O controller 104 receives switch signals from a variety of sources, of which a calibration switch 112 , a start switch 114 , a reset switch 116 and a door switch 118 are shown. FIG. 3 also shows an internal display 120 . Also shown in FIG. 3 is a drop box load cell 13(a) and an A/D 102(a) coupled to I/O controller 104. A drop box is a standard part of some slot machines and is used to contain the overflow of coins from a hopper. For example, in FIG. 1 , a drop box might have been installed below coin hopper 10 . A drop box is similar to a hopper, in that it holds a collection of coins, but differs from a hopper in that coins are not ejected from the drop box. If a drop box is used, a hopper may have a sensor, such as a coin weighing apparatus of the present invention, which detects when the hopper is full. If the hopper is full, coins are ejected from the hopper in such a way that the ejected coins fall into the drop box instead of into payout tray 4. Drop box load cell 13(a) performs a function similar to the coin hopper load cell 13 insofar as it provides an indication of the weight of a drop box (not shown) and the coins therein. This drop box load cell 13(a) may preferably be configured in any of the ways previously described. Along the same lines, a coin weighing apparatus of the present invention could be used to weigh coin fill bags which are stored in the slot machine to conveniently replenish empty coin hoppers as well as other types of drop containers. Theft or fraud can be detected by such a coin weighing apparatus when the weight of the fill bag changes without good cause. I/O controller 104 also reads/writes data from a data pin 124 (see FIG. 1 ). In a preferred embodiment, data pin 124 is part of a communication system manufactured by Dallas Semiconductor. A data wand (not shown) is a hand-held, battery-powered device with an internal computer which communicates with I/O controller 104 through a single signal line and chassis ground connection. In one application, a data wand can be used in conjunction with data pin 124 to calibrate the coin weighing apparatus 12, 22, 43, 50. In operation, load cells 13, 13(a) are provided with load cell power from a load cell power source 122 and generate an analog voltage which is a function of their load. This analog voltage is input to the load cell's A/D 102 or 102(a). FIG. 4 is a flowchart of a process for detecting coin fraud or theft by a service technician. This process is controlled by CPU 106 according to instructions stored in program memory 108. Each step in FIG. 4 is numbered with a sequential step number, except where noted. The process shown in FIG. 4 begins when hopper door 2 (see FIG . 1 ) is opened (S1). This process assumes that the primary mode of coin theft is from dishonest technicians or other casino employees opening slot machine door 2 to perform actual or purported maintenance and taking coins from hopper 10 while hopper door 2 is open. Presumably, a game cannot be played and a payout cannot be made while door 2 is open and therefore a coin count should not change except in cases of authorized coin withdrawal. In a preferred embodiment, hopper door 2 is secured by an electronic switch, such as a solenoid 126 (see FIG. 1 ), which can only be activated by the technician or employee touching their assigned data wand to data pin 124. As part of the opening process, CPU 106 records an employee ID communicated from the data wand before activating solenoid 126 to open hopper door 2 . Alternatively, hopper door 2 can be opened by an ordinary key and the door opening can be detected by door switch 118 . In either case, a preferred embodiment records the time of opening. When hopper door 2 is being opened (S1), or preferably just before hopper door 2 moves, a coin count (C) is obtained (S2) and the count is stored (S3) as the opening count (OC). If CPU 106 makes continuous, periodic readings, then the opening count (OC) might just be the most recent periodic reading before hopper door 2 was opened and after the last game was played. At step S4, the door is monitored until it is closed, and another coin count is taken (S5). In a preferred embodiment, this second coin count is a reading taken after slot machine 1 has stabilized following the closing of the door. This coin count, C, is stored (S6) as the closing count (CC). Next (S7), an expected change count (EC) is determined. This expected change count is positive in the case where a technician is sent to a slot machine to add coins to a depleted hopper, is negative where the technician is sent to the slot machine to remove coins, and is zero where the technician is sent to the slot machine simply to perform maintenance. Of course, other variations of this scheme are also possible. For example, the expected change count might not be known at the time the coins are removed, but later determined after the technician turns over the coins removed from the slot machine. If the expected change count is known at the time the door is closed, a deficiency can be easily calculated (S8), by subtracting the closing count (CC) from the opening count (OC) and adding the expected change count (EC). If the resulting deficiency (D) is not equal to zero (S9), then an alarm can be set (S10). Where the slot machine does not automatically determine the identification of the technician or other employee opening the slot machine, the setting of an alarm might result in a flashing light on the slot machine being immediately activated, so that the unauthorized removal of coins can be detected by a floor manager while the thief is still present at the machine. However, in a preferred embodiment, the slot machine detects the time of opening and closing as well as the identification of the person opening the machine, thereby allowing the deficiency to be easily traced to a specific employee. In an alternate embodiment, where the slot machine is not able to determine the identity of the person opening the slot machine, the slot machine will merely record the time of entry and the deficiency for later comparison to a log kept elsewhere showing which employees had access to which slot machines at which times. In a preferred embodiment, the alarm is not merely a local alarm in the form of a flashing light on the slot machine or the like, but is an alarm which is recorded by CPU 106 and is communicated to a central security station (not shown). Regardless of whether an alarm is set or not, the flow of the process returns to step S1, where it remains until the hopper door is again opened. While the process shown in FIG. 4 will detect unauthorized removal of coins when a hopper door 2 is open, it does not necessarily detect unauthorized removal of coins when hopper door 2 is closed. The latter type of unauthorized coin removal might arise when the dishonest employee or technician modifies the slot machine to eject or reroute coins out of the hopper 10 into other spaces inside slot machine 1 for later retrieval. This latter type of closed door removal may also occur when a dishonest player tampers with the coin in or coin out mechanisms of the slot machine. This manner of closed door theft can be counteracted by monitoring the rate at which coins fail to reach hopper 10 or fail to be counted as they are ejected by comparing hopper weight to the "coin in" or "coin out" pulses to the I/O controller 104 and CPU 106 (FIG. 3). Similarly, if a dishonest player inserts slugs or other types of counterfeit coins into the slot machine which have a different weight than valid coins, a comparison of the expected weight of valid coins in the coin hopper with the actual weight of counterfeit coins in the coin hopper can be used to detect this type of fraud. With centralized monitoring of slot machine activity, the unaccounted for loss of coins or discrepancy in coin weight while hopper door 2 is closed can be monitored for each slot machine and those slot machines with higher than normal rates of coin loss or coin weight discrepancy can be carefully inspected. Coin loss from the hopper to the drop box during normal operation can be accounted for through the use of load cell 13(a) and ADC 102(a) , as described above. In a preferred embodiment, the slot machine activity is communicated to a central security station for easy monitoring and prompt detection of deficiencies. The automatic coin accounting process of FIG. 4 is a process which can be run independently of the coin counting processes shown elsewhere. The use of the present invention to handle other modes of theft or coin accounting should be apparent after reading this present description. While FIG. 4 shows a process of deficiency detection, FIG. 5 shows a more general process of taking a reading to calculate coin count C. In a preferred embodiment, the processes of FIG. 4 and the processes of FIG. 5 run asynchronously, with the process shown in FIG. 5 being a process of periodically taking a reading to update the current coin count while the process shown in FIG. 4 (more specifically steps S2 and S5) merely refers to an episodic coin count when the slot machine door 2 is opened or closed. Referring now to FIG. 5, the process shown therein begins with an initialization of the variables used (S21). At this point, the operator is prompted with "START" or a similar prompt, prompting the operator to begin the calibration process. The prompt is displayed, in some embodiments, on a computer terminal, while in other embodiments it is displayed on an internal display 120 coupled to I/O 104 (see FIG . 3 ). Preferably, the operator first determines that the hopper and slot machine are stable and the hopper is empty. At step S22, CPU 106 (see FIG. 3 ) determines whether diagnostics were requested by the operator. In one embodiment, the operator signals that diagnostics are requested by sending a predetermined signal from a terminal to I/O controller 104 such as through the data pin I/O or by simultaneously pressing calibration button 112 and start button 114 (see FIG . 3 ). If diagnostics are requested, CPU 106 executes those diagnostics (S23) and proceeds to step S24. Otherwise, if diagnostics are not requested, CPU 106 proceeds directly to step S24. At step S24, CPU 106 checks to see if the operator has requested a calibration. In the embodiment shown in FIG. 6 , the operator requests calibration by pressing calibration button 112 . If calibration is requested, the calibration process is executed (S25) to determine a tare weight (TW) and a per coin weight (CW). Following the calibration step, which is described in further detail in FIG. 6 or if calibration is not requested, CPU 106 proceeds to step S26, where it determines whether or not the hopper was calibrated. If the hopper was not calibrated, either because calibration was not requested or because the calibration step was not successful due to unreliable readings, CPU 106 returns to step S24, thus creating a loop that is only exited when the hopper is finally calibrated. When the loop is exited, CPU 106 proceeds to step S27 , where a reading of the hopper weight is taken and a coin count is calculated. This process is shown in further detail in FIG. 6. Once a reliable coin count is obtained (S28), that coin count is displayed, transmitted to a remote storage and/or display device or the coin count is simply stored in variable memory 110 (see FIG . 3 ) for later provision of a coin count value to other processes which use the coin count. Once the coin count is obtained and processed as described above, CPU 106 returns to step S24. Thus, while the hopper remains calibrated, CPU 106 executes a periodic loop of taking a reading, calculating a coin count, and providing the coin count to various display or memory devices as needed. In a preferred embodiment, a latest reliable value for the coin count is retained and is not overwritten by any subsequent unreliable coin counts, thereby providing a reliable coin count value which can be polled at any time by asynchronous processes. FIG. 6 shows the calibration process of step S25 in further detail. At the outset of the calibration process, CPU 10 6 waits ( S41) for a calibration signal, either from a remote device or from the operator pressing calibration switch 112 . If the calibration signal is not received within a predetermined time, the calibration process is aborted and an indication that calibration did not complete is given so that readings (see FIG. 5 ) will not be taken until the calibration process actually successfully completes. If the calibration signal is received, CPU 106 proceeds to obtain the hopper weight (S43), which is described in further detail in FIG. 7 . Prior to receipt of the calibration signal, the hopper should have been emptied by the operator so that a tare weight of the hopper can be obtained. Also, if the calibration signal is sent using calibration switch 112, CPU 106 delays for a predetermined time to allow for dampening of slot machine vibrations due to calibration switch 112 being pressed. If the hopper weighing process returns an error indicating that a reliable hopper weight cannot be obtained, CPU 106 aborts the calibration process (S42). However, if a reliable hopper weight is obtained, that hopper weight is stored as the new tare weight (TW) value for the hopper (S44). Once the hopper tare weight is obtained, CPU 106 waits for a COIN WEIGHT signal (S45), and when the COIN WEIGHT signal is received, CPU 106 again measures the hopper weight (S47). Before the COIN WEIGHT signal is sent, the process expects that the hopper now contains N coins. In a preferred embodiment, N=20, however it should be apparent that other values of N could be used. If a time out occurs while waiting for the COIN WEIGHT signal or the hopper weighing process returns an error, the calibration process is aborted (S46) and only the tare weight is updated. Where a hopper is modified or moved to a different slot machine, the calibration procedure could be allowed to abort at step S46, without ill effects, since the prior per coin weight can be reused. Once the hopper weight is obtained (S47) for the hopper and the N coins, a coin weight is calculated (S48) by subtracting the hopper tare weight (TW) from the just measured hopper weight (HW) and dividing the difference by N. This new per coin weight (CW) is then stored ( S49 ) in variable memory 110 , preferably compared with a known per coin weight, and, if the measured per coin weight favorably compares with the known per coin weight, the calibration process returns indicating a successful hopper calibration. FIG. 7 shows the process of getting a hopper weight, the result being either returning successfully with a hopper weight (HW) or returning an error indicating that the hopper was too unstable for a measurement to have been taken. At the beginning of the process, the variables used for temporary storage and loop control are initialized ( S60 ) and a sampled digital value, L, is taken from load cell 13 ( S61 ). As should be apparent from this description, the processes of FIGS. 4-8 are equally applicable to coin accounting using a drop box, with the main difference being that load cell 13(a) is sampled instead of load cell 13 . The sampled value L is stored as a reference reading R (S62), and a main loop is entered. In the main loop, the load cell is again sampled (S63) to obtain a new value for L. If the absolute value of the difference between L and the reference reading R is less than a variance limit, V, then the sampled value L is added to an accumulator (HW) and a loop counter (I) is incremented (S65). CPU 106 then pauses for a predetermined delay period of T1 milliseconds (S66) and then loops back to step S63 to take another reading. This continues until a predetermined number, C_SAMP, of readings has been taken. Once C_SAMP readings have been taken and accumulated, the value in the accumulator (HW) is divided by C_SAMP (S68), to yield a hopper weight. In a preferred embodiment, the digital values L and R are integers ranging from zero to 16,383 , the variance threshold V is 120, T1 is 100 milliseconds and C_SAMP=40. If the absolute value of the difference between L and R is greater than or equal to V, indicating too much variance between a sampled weight and a reference weight, the reference weight is adjusted by an increment VSTEP (S69). More specifically, R is adjusted so that the absolute value of the difference between L and R is reduced by VSTEP, i.e., if R is greater than L by more than V, R is reduced by VSTEP and if R is less than L by more than V, R is increased by VSTEP. In a preferred embodiment, VSTEP=10. Following the adjustment of R, the loop counter (I) and the accumulator (HW) are zeroed (S70) and an unstable reading counter, U, is incremented. If the unstable reading counter U is not greater than a maximum UMAX, then CPU 106 reenters the main loop just before step S66. Otherwise, if U is greater than UMAX, U is reset to zero and an error count (ERRCNT) is incremented (S72). If the error count is greater than a maximum error value (ERRCNT > MAXERR), the hopper weight process ends and an error indication is returned. Otherwise, CPU 106 reenters the main loop just before step S66. In a preferred embodiment, UMAX=40 and MAXERR=4. Also, in a preferred embodiment, as instability is detected, the operator is provided with an indication, such as a display "UNST", to indicate that instability is being detected, thereby giving the operator the opportunity to eliminate the source of instability while a reading is being taken. Assuming a valid hopper weight reading is obtained, this can be used in the calibration process shown in FIG. 6 . FIG. 8 shows the process of taking a reading, which results in either a coin count C being returned or an error indication being returned. At the outset of this process an accumulator (HW) and a loop counter (not shown) are initialized. In the main loop (shown as steps S81, S82, S83) a load cell is sampled to obtain a value L, CPU 106 delays for T2 milliseconds, and the sampled value L is added to the accumulator (HW). This loop repeats until N_SAMP samples are taken. In a preferred embodiment, T2 is 200 milliseconds and N_SAMP=30. Once N_SAMP samples are taken, the accumulator (HW) is divided by N_SAMP (S85) and the resultant hopper weight (HW) is compared to the hopper tare weight (S86). If the hopper weight HW is less than the tare weight TW, an error signal is generated (S87), otherwise a coin count C is calculated according to the formula: C=ROUND((HW - TW)/ CW). Of course, other suitable formulae can be used. The hopper weight reading process of FIG. 8 is less interactive and less error-correcting than the hopper-weight reading process of FIG. 6 , since the former generally occurs when the slot machine is not open and an unreliable reading can be discarded without ill effects, whereas the latter process provides tare weight and per coin weights which cannot be as easily discarded. Thus, in the manner described above, a hopper is weighed periodically and that weight is used, combined with an automatically determined per coin weight, to determine a number of coins in the hopper. In one specific use of the coin count, coins are counted as the hopper door is opened and then counted again after the hopper door is closed and this difference is compared to an authorized difference to determine if unauthorized removal of coins from the hopper while the hopper door was open occurred. One application of this system includes a centralized slot machine control system, from where a trusted employee can monitor the opening and closing of each slot machine door, as well as a current inventory of the coins in the hopper and/or drop box of each slot machine. The necessary information can be communicated from the slot machines to the centralized slot machine control system through dedicated communication lines running fron each slot machine or can be provided by the above described data pin system.

Claims: A weighing apparatus in a gaming, amusement or vending machine comprising: an upper plate supporting a coin hopper (10); a base (14); an elongated load cell (12) , incorporating a strain gauge, interposed between and attached to both said upper plate and said base, spacers (16a, 16b) interposed between said load cell and each of said upper plate and said base, wherein said load cell (12) being in the shape of a rectangular prism and wherein diagonally opposite edges of said load cell being attached to said upper plate and said base (14), characterized in that the load cell (12) is arranged with it's long dimension perpendicular to the longitudinal axis of the coin hopper. The weighing apparatus in accordance with claim 1 , whereby that said gaming, amusement or vending machine is a slot machine, preferably an amusement with payout machine. The weighing apparatus in accordance with claim 1 , whereby it further comprises an analog-to-digital converter connected to said strain gauge. A method of coin theft detection in a gaming, vending or amusement machine, said machine comprising a weighing apparatus in accordance with claim 1 , said method comprising the steps of a first weighing step of weighing coins in a coin hopper of said gaming machine using a weighing apparatus which is built into said coin hopper, thereby measuring a first weight; a first calculating step of calculating a number of coins in the coin hopper based on the first weight, resulting in a first count; allowing access to the coins in the coin hopper; a second weighing step of weighing coins in a coin hopper of said gaming machine using a weighing apparatus which is built into said hopper, thereby measuring a second weight; a second calculating step of calculating a number of coins in the coin hopper based on the second weight, resulting in a second count; and setting an alarm if the second count is less than the first count minus an authorized number of removed coins. The method in accordance with claim 4 , wherein the first and second steps of weighing coins are steps of weighing coins of known unit weight. The method in accordance with claim 4 , wherein the first and second steps of weighing coins are steps of weighing coins and the coin hopper. The method in accordance with claim 4 , wherein the steps of weighing coins comprise the substeps of: measuring an acceleration of the coin hopper relative to the gaming machine; and measuring a distortion of a cantilever beam which is distorted by the weight of the coin hopper and the coins therein when the acceleration of the coin hopper relative to the gaming machine is essentially zero or is a known acceleration. The method in accordance with claim 4 , comprising the steps of: detecting a door being opened; substantially simultaneously with the door being opened, measuring a first number of coins in the coin hopper by weight using a coin weighing apparatus which is built into said coin hopper; detecting the door being closed; measuring a second number of coins in the coin hopper by weight after the closing of the door is detected using a coin weighing apparatus which is built into said coin hopper; and determining a difference in coin count by subtracting the first count from the second count and electronically reporting the difference to a theft control system. The method in accordance with claim 8, wherein the step of reporting the difference comprises the step of setting an alarm. The method in accordance with claim 9 , wherein the step of setting alarm is a step of setting a flag in a field of a row of a data table associated with the gaming machine in which the difference is detected. The method in accordance with claim 4, comprising the steps of: weighing coins in a coin hopper of said gaming machine using a coin weighing apparatus which is built into said coin hopper to determine a baseline weight at the start of a detection period; calculating a baseline coin count from the baseline weight; recording a number of inserted coins; recording a count for each authorized withdrawal of payout; calculating an expected coin count by subtracting the count for each authorized withdrawal or payout from the baseline coin count and adding the number of inserted coins thereto; weighing coins in the hopper at the end of the detection period to determine a final hopper weight using a coin weighing apparatus which is built into said coin hopper; calculating a final coin count from the final hopper weight; and determining a discrepancy amount for the detection period by subtracting the final coin count from the expected coin count. The method in accordance with claim 11 , further comprising the step of reporting the discrepancy amount as a coin theft amount. The method in accordance with claim 4 , to detect coin theft from a fill bag in the gaming, amusement or vending machine, comprising the steps of: a first weighing step of weighing coins in a fill bag in said machine, a first calculating step of calculating a number of coins in said fill bag based on the first weight, resulting in a first count; allowing access to said fill bag; a second weighing step of weighing coins in said fill bag after allowing access, thereby measuring a second weight; a second calculating step of calculating a number of coins in said fill bag based on the second weight, resulting in a second count; and setting an alarm if the second count is less than the first count minus an authorized number of removed coins. A method in accordance with claim 4 for of detecting insertion of counterfeit coins into a coin hopper of a gaming, amusement or vending machine comprising the steps of: ascertaining the weight of a valid coin; sensing the number of coins inserted into said machine; weighing the total number of coins collected in said coin hopper of said machine; dividing the weight of coins collected in said coin hopper by the number of coins sensed to determine the average weight of coins in said coin hopper; comparing the average weight of coins in said coin hopper to the weight of a valid coin to ascertain whether counterfeit coins are being inserted into said coin hopper. The method of claim 14 , further comprising the step of adjusting the difference to account for authorized coin removals. The method of claim 15 , further comprising a step of setting an alarm when the difference is greater than zero. The method of claim 16, wherein the step of setting an alarm is a step of, setting a flag in a field of a row of a data table associated with the gaming machine in which the difference is detected. The method of claim 17, comprising the weighting apparatus of claim 1 and further comprising the steps of: weighing coins in a coin hopper of said gaming machine using a coin weighting apparatus which is built into said coin hopper to determine a baseline weight at the start of a detection period; calculating a baseline coin count from the baseline weight; recording a number of inserted coins; recording a count for each authorized withdrawal of payout; calculating an expected coin count by subtracting the count for each authorized withdrawal or payout from the baseline coin count and adding the number of inserted coins thereto; weighing coins in the hopper at the end of the detection period to determine a final hopper weight using a coin weighing apparatus which is built into said coin hopper; calculating a final coin count from the final hopper weight; and determining a discrepancy amount for the detection period by subtracting the final coin count from the expected coin count. The method of claim 18 , further comprising the step of reporting the discrepancy amount as a coin theft amount.

Inventors: COULTER GARY L, FILIBERTI PETER, KARABIN JUDITH, COULTER, GARY L., FILIBERTI, PETER, KARABIN, JUDITH
Applicants: SPINTEKNOLOGY INC, SPINTEKNOLOGY INC.
Application year: 1996
Main classification: G01G19
IPC codes: G01G19, G07F17, G07F9