EP0308996A2 - Coin validators - Google Patents
Coin validators Download PDFInfo
- Publication number
- EP0308996A2 EP0308996A2 EP88117267A EP88117267A EP0308996A2 EP 0308996 A2 EP0308996 A2 EP 0308996A2 EP 88117267 A EP88117267 A EP 88117267A EP 88117267 A EP88117267 A EP 88117267A EP 0308996 A2 EP0308996 A2 EP 0308996A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- coin
- validator
- processor
- circuit
- oscillator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- G—PHYSICS
- G07—CHECKING-DEVICES
- G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
- G07D5/00—Testing specially adapted to determine the identity or genuineness of coins, e.g. for segregating coins which are unacceptable or alien to a currency
- G07D5/02—Testing the dimensions, e.g. thickness, diameter; Testing the deformation
-
- G—PHYSICS
- G07—CHECKING-DEVICES
- G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
- G07D5/00—Testing specially adapted to determine the identity or genuineness of coins, e.g. for segregating coins which are unacceptable or alien to a currency
- G07D5/08—Testing the magnetic or electric properties
Definitions
- This invention relates to coin validators, and is particularly, but not exclusively, concerned with validators which use very little power, and which are therefore suitable for use in, for example, pay telephones.
- EP-A1-0058094 describes a coin validator which provides very accurate and reliable results, and which consumes very little power.
- the present invention is concerned with further improvements in this field.
- a coin validator having an arrival sensor for sensing the arrival of a coin at a sensing station, the validator being characterised by a processor having a first state in which it performs processing operations and operates at a relatively high current level, and a second state in which it operates at a relatively low current level, and means for periodically causing the processor to enter the first state in order to determine, using said arrival sensor whether a coin has arrived.
- the processor is caused to perform, in its first state, a validity checking operation in response to arrival of the coin as detected by the arrival sensor.
- the processor is preferably a microprocessor.
- the arrival of a coin is detected by performing, periodically, a measurement using the arrival sensor, and determining that a coin has arrived if measurements produce values which change in a predetermined manner.
- the last two measurements taken of the frequency of the output of the arrival sensor are considered, and if that frequency found to have increased by more than a predetermined amount, it is determined that a coin has arrived at the sensor. This determination is made in response to measurements taken over a short period, and therefore the effects of drift caused by, e.g. temperature changes or aging of components, does not have any material effect upon the detection of coin arrival.
- the processor is preferably activated periodically only long enough to perform a measurement and determine whether a coin has arrived. The processor then returns to its second state, to reduce power consumption, unless coin arrival is detected in which case a validation operation is performed.
- a circuit is provided for automatically resetting the processor after the processor has been caused to enter its active state unless the circuit is inhibited from doing so by the processor itself.
- the processor will inhibit the operation of the resetting circuit, but if the processor "hangs-up", i.e. ceases to operate properly, it will automatically be reset so that proper operation of the processor can be recommenced.
- the resetting circuitry can also be arranged to respond to other signals; for example, it can be responsive to an output of the processor and causes resetting if a signal at the output lasts for more than a predetermined interval.
- a counter is arranged to count, following the activation of the processor, and to cause resetting if a predetermined count is reached. Under normal circumstances the counter would be cleared by the processor before this predetermined count is reached. The counter may also be used for periodically causing the processor to enter its first state.
- the output of the arrival sensor can be measured by using a counter (possibly the above-mentioned counter) which is caused to count the oscillations of the arrival sensor for a predetermined period to produce a count representing frequency.
- This method can also be used during the validation operation to produce a measure of a parameter (preferably diameter) of the coin.
- the arrival sensor is an inductive sensor which is also used in the testing of coins for providing a signal which is indicative predominantly of the diameter or surface area of the coin.
- it is the frequency of the signal which is used as an indication of diameter or surface area. in view of the relationship between diameter and surface area, the testing of either of these parameters will be, for simplicity, referred to herein merely as diameter testing.
- the inductance of the arrival sensor is confined to one side of the coin path. This differs from the arrangement described in the earlier Patent Specification mentioned above, in which the arrival sensor is used for measuring coin thickness, and comprises coils mounted on both sides of the coin path.
- the arrival sensor comprises an inductance coupled to an amplifier so as to produce an oscillator having a frequency dependent upon the value of the inductance, and thus varying in response to a coin coming into proximity to the inductance, at least a substantial part of the load of the amplifier being independent of the presence of a coin.
- the oscillator is a Colpitt's circuit.
- the output current of the amplifier is derived via a fixed impedance, preferably a resistor.
- the inductance is preferably coupled between the output and the input of the amplifier to produce feedback and cause oscillation.
- the above features are intended to provide an arrival sensor which requires very little current in order to be able to detect the arrival of a coin, and preferably which also can carry out a testing operation while consuming only a small amount of current, and preferably without requiring the current used for arrival sensing to be increased as is done in the circuit described in the above-mentioned earlier Patent Specification.
- the signal from the arrival sensor undergoes relatively little attenuation as a coin passes the coil.
- the sensing circuit can be operated at low current without risking disappearance of the signal upon arrival cf a coin. Because it is the frequency of the signal which is used for detecting coin arrival, the relatively small change in amplitude does not detrimentally affect the sensitivity of the circuit.
- a diameter-testing inductance which may be the arrival sensor and which may be formed of a printed circuit, has a height which is substantially equal to its width.
- the overall shape of the inductance may be substantially square, or preferably circular.
- the lower edge of the inductance is at or slightly below the bottom of the surface on which the coin rests as it passes the inductance.
- the maximum area of the inductance covered by a coin as it passes the inductance will depend on the coin diameter. Better discrimination can be achieved in this way, in which the area covered increases with the square of the diameter, than in an arrangement in which the inductance is elongate so that the length covered varies in proportion to the diameter.
- the coin validator does not normalise the speed of coins delivered to a sensing station thereof, and has means responsive to a value indicative of the speed at which a coin is travelling through said sensing station for providing a signal indicating that the coin is not acceptable in response to determining that the coin has travelled too fast through the sensing station.
- the coin speed may be detected by measuring the interval between the coin passing two separate sensors and/or by measuring the rate of change of an output signal of a single sensor.
- Such an arrangement is particularly valuable in small coin validators where the distance between a coin entry slot and the coin sensors is short and therefore there is severe risk that the coin's motion when it reaches the sensor will not have stabilised to such an extent as to ensure accurate test results.
- US-A-3797628 discloses a coin validator in which token velocity is measured in order to determine whether a coin is acceptable. However, this is concerned with a different type of validator, in which the velocity of an inserted coin is normalised and then altered in accordance with the properties of the coin, so that the velocity measurement is in effect a test of the coin, rather than a test of whether the coin's flight is suitable for validation.
- the validator 2 has a main processor 4 which uses an arrival/diameter sensing circuit 6 and a material/thickness sensing circuit 8 for detecting the arrival of coins and for testing those coins and providing signals indicating whether a coin is genuine, and if so the type of the coin.
- the arrival/diameter sensing circuit 6 has a sensing coil 10 connected in an oscillator circuit to be described in more detail subsequently.
- the coil 10 is situated at one side of a coin passageway 7.
- the passageway 7 is inclined and canted so that coins, such as that shown at 9, travel down the passageway 7 in the direction A with their faces in contact with the side of the passageway on which the coil 10 is located.
- the circuit 6 is so arranged that the signal appearing at the output 12 of the circuit 6 has a frequency which alters as a coin passes the coil 10, and which peaks at a level predominantly dependent upon the diameter of the coin.
- the material/thickness sensing circuit 8 has a coil 14 disposed at the opposite side of the coin passageway 7 from the coil 10.
- the coil 14 is connected in an oscillator circuit, and the circuit is so arranged that the signal appearing at the output terminal 16 is attenuated in response to a coin passing the coil 14.
- the peak level of attenuation is predominently dependent upon the material from which the coin is made, and the thickness of the coin. Because the coin contacts the side of the passageway 7 opposite to that on which the coil 14 is located, the spacing of the coin from the coil will depend upon coin thickness, so that it is ensured that this will have a significant effect on the output of circuit 8.
- the processor 4 is a CMOS 8048 (or CMOS 8049) microprocessor. This has terminals P1, P2, P3, P4 and P5, which can be used as, respectively, a clock output terminal, an interrupt input terminal, a reset input terminal, an input/output terminal and a testable input terminal. There are also address/data bus terminals D. The remaining terminals referred to below are further input/output terminals which, unlike the terminal P4 which is used at different times as both an input and an output, are only required to perform a single input or output function in the particular circuit shown.
- the processor 4 also has power supply terminals, clock input terminals etc. which are not shown in Fig. 2.
- the processor 4 has in its instruction set a HALT instruction, which when executed causes the processor to enter a quiescent state, in which no processing operations are carried out and the power consumption is substantially reduced.
- the processor can be switched back to an active state by a signal on the interrupt terminal P2.
- the validator is installed in a pay telephone. Under normal circumstances the entire validator is switched off. When the handset is lifted, parts of the validator circuit, including the processor 4 and arrival/diameter sensing circuit 6, but excluding the material/thickness sensing circuit 8, are switched on.
- the processor 4 then executes an initialisation routine, following which a HALT instruction is executed so that the processor enters a quiescent state.
- the oscillations appearing at the output terminal 12 of the arrival/diameter sensing circuit 6 are delivered via gates 18 and 20 to the clock input 22 of a counter 24.
- the counter has output terminals C1 to C10.
- the counter counts the pulses until a signal appears at count output C10.
- This signal is delivered to the interrupt terminal P2 of the processor 4 in order to cause the processor to enter its active state.
- the processor then proceeds to issue on line 26 a clear signal which is delivered to the clear terminal 28 of the counter 24.
- the processor also delivers on line 30 a signal for closing the gate 18.
- the processor 4 then temporarily opens the gate 18 for a predetermined duration.
- the counter 24 is thus caused to count the pulses appearing at the output terminal 12 of the circuit 6.
- the final count, which appears at the count terminals C1 to C8, is noted by the processor 4 which has input/output terminals connected to those count terminals, before the counter 24 is cleared by the processor.
- the processor 4 has a memory into which the count is stored, the arrangement being such that the memory always stores the previous count measured in this way.
- the processor determines that a coin has arrived at the coil 10 if the second count exceeds the first by more than a predetermined number. Thus, a coin is detected in response to an increasing frequency appearing at the output terminal 12.
- the processor 4 Assuming that a coin has not been detected, the processor 4, after clearing the counter 24, opens the gate 18 and executes the HALT instruction. The processor 4 will then adopt its quiescent state until a signal appears once more at the count terminal C10.
- the processor is thus regularly caused to enter its active state in order to determine whether or not a coin has arrived, and if not the processor re-enters its quiescent state. This may occur at intervals of, for example, 5 milliseconds, the processor being active for a period of less than 1 millisecond during each of these intervals. The average current consumption of the processor 4 is thus low.
- the processor 4 then continues to sample the frequency of the signal appearing at the terminal 12. The frequency continuously increases until a peak is reached, following which the frequency decreases until an idling level is reached, after the coin has left the coil.
- the processor 4 recognises and stores the peak and idle levels, and thereafter calculates the ratio of these two levels in order to produce a diameter-indicating value.
- the processor issues on line 32 a signal for operating a power switch 34. This causes the power supply to be connected to the material/thickness sensor circuit 8.
- the processor 4 may be arranged to switch on the material/thickness sensor circuit 8 immediately after the detection of the arrival of a coin to ensure that the operation of circuit 8 has stabilised by the time the coin reaches coil 14. Alternatively, to conserve power, the processor 4 may be arranged to switch on the circuit 8 after detection of the peak in the output frequency of the signal at terminal 12, or possibly when the processor 4 has detected that the frequency has dropped to an idling level.
- the processor 4 may be arranged to check that the diameter value is appropriate for a genuine coin of a denomination which the validator is arranged to accept before switching on the circuit 8. In this way, the circuit 8 will not be operated unless the coin has an acceptable diameter, and thereby power consumption is further reduced.
- the processor 4 issues a signal on line 30 to close the gate 18, so that no more pulses from the circuit 6 can reach the counter 24.
- the counter is cleared, and the processor issues a signal on line 36 to open a gate 38. This permits the gate to pass pulses from the terminal P1 via the gate 20 to the clock input terminal 22 of the counter 24.
- the counter 24 thus counts up at a constant, predetermined rate.
- the count terminals C1 to C8 are connected via resistors R1 to R8 to respective points on a series resistor network R9 to R16 coupled between ground and one input 40 of a comparator 42.
- the other input.44 of the comparator 42 is connected to the output terminal 16 of the circuit 8.
- the resistors R1 to R16 act as potential dividers in such a manner that a signal at any one of the count output terminals C1 to C8 will produce, at the input terminal 40 of the comparator 42, a voltage corresponding to the respective count terminal. The effect of this is to cause the voltage at the terminal 40 to increase progressively in a stepwise manner as the count reached by the counter 24 increases.
- the resistors are of close tolerance to ensure an even distribution of the voltages produced as the count increases.
- the counter 24 is then cleared, the terminal P4 switched to behave as an output terminal, and the gate 38 re-opened so as to permit the processor 4 to take a further measurement of the output signal appearing at terminal 16 of the circuit 8.
- the comparator 42 has an open-collector output so that this and the terminal P4 can be directly connected to the gate 38, whereby each can control gate 38, without interfering with each other.
- the processor 4 repeatedly measures the output appearing at terminal 16, and determines from these measurements the idle value. This is done before the coin reaches the sensor coil 14, and may be initiated by the circuit 6 sensing the departure of the coin from coil 10. Then as the attenuation increases during the movement of the coin past the sensor, the peak value of the signal is determined. This is preferably achieved by storing successive measurement values. The processor detects when these values alter in such a manner as to indicate that the attenuation is decreasing due to the coin leaving the sensor. The processor then averages the stored values, preferably ignoring the more recent measurements so that the values used represent measurements taken when the coin was substantially at the mid-point of its travel past the sensor.
- the processor may be arranged to take the average of the first, say, four of the last twelve measurements.
- the processor could simply sum the values without dividing the result; the stored ranges would be correspondingly greater.
- the circuit 8 is switched off, the counter 24 is cleared and the gate 18 is re-opened to allow the pulses appearing at output terminal 12 of circuit 6 to reach the counter 24.
- the processor 4 For each of the denominations of coins which the validator 2 is designed to accept, the processor 4 stores information defining a diameter range and a material/thickness range. For example, the processor 4 may store upper and lower limits of the respective ranges, or alternatively may store a single value from which the processor can calculate, using a stored or predetermined tolerance, the appropriate range.
- the processor 4 compares the two measurements, i.e. the diameter value and the thickness/material value, with the ranges for the respective coins, and determines that a valid coin of a particular denomination has been received if both values fall within the appropriate ranges for that denomination. In that case, the processor 4 produces on one or both of data lines 46 an ACCEPT signal, and on lines 48 a binary signal indicating the denomination of the coin.
- the coin validator 2 is intended for installation in various types of machines, e.g. gaming machines. In some of these, it is desired that the machine be capable of accepting a first range of coins (e.g. 5p, 10p, 20p and 50p U.K. denomination coins), and in other machines a different range (e.g. 10p, 20p, 50p and £1 coins). To cater for this without requiring different types of validator to be manufactured, the validator is arranged to recognise all five coins and generate ACCEPT signals on lines 46 in accordance with the range of coin denominations within which a received coin lies. Thus, if the denomination of a received coin falls within both ranges (e.g.
- an ACCEPT signal is generated on both lines 46, and the coin denomination indicated by the data on lines 48. If the coin denomination lies in only one range (e.g. 5p), then only one of the lines 46 (corresponding to that range of denomin ations) carries the ACCEPT signal while the lines 48 carry data representing the denomination 5p. When a coin denomination which belongs only to the other range is received (e.g. a £1 coin), the same data on lines 48 can be generated, but this time the ACCEPT signal is generated on the other of the lines 46.
- the validator 2 has a reset pulse generator 50, which produces a pulse of predetermined length to reset the processor 4 in the event that any one of three conditions indicative of "hang-up" occurs.
- the output of counter terminal C10 is used to deliver a signal to interrupt terminal P2 of processor 4, which causes the processor to issue a signal on line 26 to clear the counter 24. If this does not occur, due to faulty operation of the processor 4, the counter will not be cleared and will continue to count in response to pulses from the circuit 6. Eventually, an output signal will appear at terminal C9 of the counter 24, and the simultaneous appearance of signals at terminals C9 and C10 will be detected by a gate 52, which will deliver an activating signal via a gate 54 to the circuit 50 to cause resetting of the processor 4.
- the gate 54 has two further inputs connected to respective detection circuits 56 and 58. Each of these receives a signal at its input and delays that signal, but the signal appears at the output only if the input signal lasts for more than a predetermined amount of time. Circuit 56 is connected to the clear terminal 28 of the counter 24, so that if after issuing a signal to clear the counter the processor suddenly begins to behave incorrectly, the signal at the clear input terminal 28 will persist longer than it should, and this will be detected by the circuit 56 which will issue a signal view gate 54 to circuit 50 to cause resetting of the processor 4.
- the circuit 58 has its input connected to the line 30 which carries the signal issued by the processor 4 to close the gate 18.
- the longest time for which the gate 28 is closed occurs when the processor is measuring the output of circuit 8.
- the delay of circuit 58 is set to be longer than this time. If the processor 4 begins to behave incorrectly during the thickness/material measuring operation, and the gate 18 thus remains closed, this will be detected by the circuit 58 and cause resetting of the processor.
- processor 4 Even if the processor 4 begins to behave improperly, it may nevertheless execute an interrupt routine, initiated by the signal delivered to terminal P2, in a correct manner. To detect this situation, the processor 4 is arranged to set a number of internal flags while executing the arrival detection routine. During the interrupt routine, the processor 4 checks to see that these flags are set. If they are not, because the main routine was not being executed properly, the processor 4 executes an instruction which causes it to be reset.
- the validator is preferably made in such a way that the coin measurements which are made produce fairly predictable results for given denominations, so that the parameter ranges stored by the processor 4 do not have to be specially worked out for each validator.
- the sensing circuits 6 and 8 can be adjusted in respect of frequency and/or gain to vary their outputs.
- the processor 4 can be switched into a test mode by connecting a link 59 between a power supply rail and the testable input terminal P5, which terminal is normally held at a low potential by a resistor R17 connected to ground. At the same time, the operator connects a device to the data lines D to display the potentials on these lines.
- the operator After switching the validator into the test mode, the operator inserts a coin of a particular denomination (e.g. 10p), and determines what signals are produced on the data lines 46 and 48 in response thereto.
- a coin of a particular denomination e.g. 10p
- the inserted coin is preferably specially selected so that its properties are of an average value with respect to the normal variations expected of coins of that denomination.
- test ranges correspond to the ranges used to determine whether an acceptable coin of the particular denomination (e.g. 10p) has been received, except that they are narrower than the acceptability ranges.
- the processor's output on data lines 46 and 48 is in a different format, and has a different meaning, from the outputs in the normal validation operation.
- a high-level logic signal is applied to all the output lines 46 and 48. If the value derived from the sensing circuit 6 exceeds or falls below the respective range, the lines 46 are caused to carry a binary value of "10" or "01", respectively. Similarly, if the value derived from sensing circuit 8 exceeds or falls below its respective test range, the value produced on lines 48 is "10" or "01", respectively.
- Capacitors 62 and 64 are each connected between, on the one hand, a respective end of the circuit formed by components 10, 61 and 63, and on the other hand, ground.
- the variable resistor 61 is used for the adjustment made during the test mode.
- Resistors 66, 68 and 70 are provided for biasing the transistor 60 into conduction.
- the load on the transistor 60 is distributed between a collector impedance (formed by a resistance RL and an inductance LL) and the resonant circuit formed by the components 10, 61, 62, 63 and 64.
- the output voltage appearing across the capacitor 62 is dependent to a large extent on the fixed impedance RL and LL.
- the degree of attenuation will be relatively small, because the load impedance does not change, compared with a circuit such as those used in the above-mentioned British Patent Specification No. 2093620, in which the coil is connected to the collector current path and therefore has a very substantial effect on the output voltage.
- the incorporation of inductance LL increases the stability of the output voltage with changes in frequency.
- the circuit 6 can be arranged so that it normally consumes a low level of current, but nevertheless will provide an output signal which will not disappear even when a coin is in close proximity to the coil 10.
- the circuit is, as mentioned above, also used for measuring purposes. It has been found that if the coil 10 is suitably arranged for diameter measurement, and the frequency of the output rather than the amplitude is used for measurement purposes, good discrimination can be achieved with the same low operating current as is used for arrival sensing.
- the sensing circuit 8 produced an output whose amplitude was sensed in order to provide an indication of the material and thickness of the coin.
- the sensor is used for providing an output which is predominantly dependent upon the material of the coin, and somewhat less dependent upon thickness.
- there are two coils 14 and 14′ (the latter of which is shown in phantom in Figure 1) positioned on respective sides of the coin passageway.
- the amplitude of the output of the sensing circuit 8 is used for measurement purposes; however in the present embodiment the frequency of the output is used as an additional measurement. In total, there are therefore three measurements, which are compared with respective stored ranges, and as a consequence of this the rejection of non-genuine coins is made much more reliable.
- FIG. 4 shows the circuit 8, which is additionally suitable for use in the first-described embodiment.
- the circuit has a standard oscillator configuration, using a transistor 100.
- the two coils 14 and 14′ which are in field-aiding relationship,are connected in series with each other and with a variable inductance 102.
- the inductances are connected in the collector path of the transistor 100.
- the emitter path includes a variable resistor 104.
- the microprocessor 4 is of the Motorola 6805 family. This has a plurality of ports which can be used as input or output terminals. In the arrangement shown, terminals I1 to I3 are used as input terminals, and terminals 01 to 011 are used as output terminals.
- the microprocessor 4 can operate a switch 150 which selectively delivers the output pulses of sensing circuit 6 to a divide-by-four circuit 152 formed of two flip-flops.
- the output of circuit 152 is delivered to the terminal T1.
- the internal counter can thus be used for counting pulses from the circuit 6 and hence measuring the frequency of the output.
- the states of the flip-flops in circuit 152 are detected on input lines I2 and I3 so that two extra bits of resolution can be achieved.
- the circuit 152 is released from its set state by changing the signal appearing on output terminal 05. After the measuring operation, the circuit 152 is held in a set state which allows the input terminal T1 to receive other signals, as will be described.
- the output of sensing circuit 8 is delivered via another microprocessor-controlled switch 154 to terminal T1 so that the frequency of this output can be measured.
- the divide-by-four circuit 152 is not required as the coils 14, 14′ are driven at a substantially lower frequency than the coil 10.
- the output of the sensing circuit 8 is also delivered via a rectifying circuit 156 to a comparator 158.
- Another input of the comparator 158 is connected to a junction between a constant current charging circuit 160 and a capacitor 162.
- the charging circuit 160 can be switched on or off by an output terminal 02 of the microprocessor 4.
- the internal counter measures (a) frequency of output of sensing circuit 6, (b) frequency of output of sensing circuit 8, and (c) amplitude of output of sensing circuit 8.
- the circuit operates substantially as described with reference to Figure 2. However, after the coin starts to leave the coil 10, the microprocessor 4 first measures the amplitude of the output of sensing circuit 8, then measures its frequency, and then once more measures the amplitude. The two amplitude measurements are averaged to obtain the idle amplitude value. The frequency measurement takes place over a sufficiently long time that any slight fluctuations in frequency do not affect the result.
- amplitude measurements are repeatedly taken. As the coin enters the space between coils 14 and 14′, the amplitude will start to decrease. Successive amplitude measurements are compared, and once the amplitude stops decreasing, a frequency measurement is made. Thereafter, a succession of further amplitude measurements are made, and when they indicate that the coin is leaving the coils 14, 14′, a plurality of these measurements (preferably excluding the most recent measurements) are averaged to obtain the peak amplitude value.
- This operation gives rise to three measurement values, each comprising the ratio of an idle value with the peak value, which are compared with respective ranges to determine whether the coin is valid, and if so the denomination of the coin.
- the microprocessor 4 also times the interval between the coin arriving at the coil 10 and departing from the coils 14, 14′. If this interval is less than a predetermined value, it is indicative of a coin which is travelling too fast for accurate measurement, and the coin is therefore rejected. Also, the microprocessor checks the successive values of the frequency of the sensing circuit 6, and successive values of the amplitude of sensing circuit 8, and if either of these is altering too rapidly the coin is rejected on the basis that it is travelling either too fast or in an unstable manner.
- an operator When an operator wishes to test the operation of the validator, he operates a switch or connects a link to issue a pulse to an interrupt terminal INT of the microprocessor 4 (instead of using a test terminal T1 as in Fig. 2).
- This causes the microprocessor to execute an interrupt routine which results in signals being generated on a serial data output line 010 in response to a coin passing the coils 10, 14, 14′.
- the operator inserts a coin having known characteristics, such as a coin of a particular denomination which has been chosen so as to have substantially exactly average properties.
- the microprocessor compares the three measurements produced by this coin with special ranges which are narrower than those normally used for this denomination of coin, and as a consequence the data on output line 010 indicates what adjustments need to be made to the sensing circuits 6 and 8.
- the operator has a test device connected to receive the data from output terminal 010 and clock pulses from output terminal 011.
- the device includes logic circuitry which decodes the data so as to provide a display indicating whether and in which manner any of the components 61 (Fig. 3), 102 and 104 (Fig. 4) need adjustment.
- the coil is formed by a printed circuit etched on both sides of a double-sided printed circuit board 80.
- Fig. 6A shows the side 82 of the board 80 which in use is more closely adjacent the coin path, and Fig. 6B shows the opposite side 84.
- the board 82 is located in a plane parallel to the side walls of the passageway 7.
- the printed circuit board On each side, the printed circuit board has been etched to form a spiral conductive pattern having an overall substantially circular configuration.
- the side 82 carries two terminal portions 86 and 88.
- the conductive path starts from the terminal portion 86 and then spirals inwardly to an inner contact portion 94.
- terminal portions 86 and 88′ form the opposite ends of the coil 10.
- the field created by the portion of the coil 10 on side 82 will extend in the same direction as the field produced by the part of the coil on the side 84.
- the respective parts of the coil 10 on the opposite sides of the board 80 can be positioned very accurately with respect to the coin path, so that there is good consistency in the measurements produced by the coil 10 from validator to validator. Thus, only minor adjustments using the variable resistor 61 of Fig. 3 are needed.
- the bottom edge of the coil 10 is located at or preferably slightly below the bottom of the coin path so that if a coin passing the coil 10 tends to bounce there is little or no effect upon the coil area covered by the coin and hence upon the measured value.
Abstract
Description
- This invention relates to coin validators, and is particularly, but not exclusively, concerned with validators which use very little power, and which are therefore suitable for use in, for example, pay telephones.
- EP-A1-0058094 describes a coin validator which provides very accurate and reliable results, and which consumes very little power. The present invention is concerned with further improvements in this field.
- It is known, e.g. from EP-A1-0058094, to provide an arrival sensor, which is used to sense when a coin arrives at a validator so as to initiate the powering-up of parts of the validator circuitry which are normally, in order to conserve power, either switched off or running at a relatively low power level.
- In accordance with the invention, there is provided a coin validator having an arrival sensor for sensing the arrival of a coin at a sensing station, the validator being characterised by a processor having a first state in which it performs processing operations and operates at a relatively high current level, and a second state in which it operates at a relatively low current level, and means for periodically causing the processor to enter the first state in order to determine, using said arrival sensor whether a coin has arrived.
- Preferably, the processor is caused to perform, in its first state, a validity checking operation in response to arrival of the coin as detected by the arrival sensor. The processor is preferably a microprocessor.
- Preferably, the arrival of a coin is detected by performing, periodically, a measurement using the arrival sensor, and determining that a coin has arrived if measurements produce values which change in a predetermined manner. In a preferred embodiment, the last two measurements taken of the frequency of the output of the arrival sensor are considered, and if that frequency found to have increased by more than a predetermined amount, it is determined that a coin has arrived at the sensor. This determination is made in response to measurements taken over a short period, and therefore the effects of drift caused by, e.g. temperature changes or aging of components, does not have any material effect upon the detection of coin arrival.
- The processor is preferably activated periodically only long enough to perform a measurement and determine whether a coin has arrived. The processor then returns to its second state, to reduce power consumption, unless coin arrival is detected in which case a validation operation is performed.
- Preferably, a circuit is provided for automatically resetting the processor after the processor has been caused to enter its active state unless the circuit is inhibited from doing so by the processor itself. Under normal circumstances the processor will inhibit the operation of the resetting circuit, but if the processor "hangs-up", i.e. ceases to operate properly, it will automatically be reset so that proper operation of the processor can be recommenced. The resetting circuitry can also be arranged to respond to other signals; for example, it can be responsive to an output of the processor and causes resetting if a signal at the output lasts for more than a predetermined interval.
- In a preferred embodiment, a counter is arranged to count, following the activation of the processor, and to cause resetting if a predetermined count is reached. Under normal circumstances the counter would be cleared by the processor before this predetermined count is reached. The counter may also be used for periodically causing the processor to enter its first state.
- The output of the arrival sensor can be measured by using a counter (possibly the above-mentioned counter) which is caused to count the oscillations of the arrival sensor for a predetermined period to produce a count representing frequency. This method can also be used during the validation operation to produce a measure of a parameter (preferably diameter) of the coin.
- Preferably, the arrival sensor is an inductive sensor which is also used in the testing of coins for providing a signal which is indicative predominantly of the diameter or surface area of the coin. Preferably, it is the frequency of the signal which is used as an indication of diameter or surface area. in view of the relationship between diameter and surface area, the testing of either of these parameters will be, for simplicity, referred to herein merely as diameter testing.
- Preferably, the inductance of the arrival sensor is confined to one side of the coin path. This differs from the arrangement described in the earlier Patent Specification mentioned above, in which the arrival sensor is used for measuring coin thickness, and comprises coils mounted on both sides of the coin path.
- Preferably the arrival sensor comprises an inductance coupled to an amplifier so as to produce an oscillator having a frequency dependent upon the value of the inductance, and thus varying in response to a coin coming into proximity to the inductance, at least a substantial part of the load of the amplifier being independent of the presence of a coin. In a preferred embodiment the oscillator is a Colpitt's circuit. Preferably, the output current of the amplifier is derived via a fixed impedance, preferably a resistor. The inductance is preferably coupled between the output and the input of the amplifier to produce feedback and cause oscillation.
- The above features are intended to provide an arrival sensor which requires very little current in order to be able to detect the arrival of a coin, and preferably which also can carry out a testing operation while consuming only a small amount of current, and preferably without requiring the current used for arrival sensing to be increased as is done in the circuit described in the above-mentioned earlier Patent Specification.
- By using the circuit described above, the signal from the arrival sensor undergoes relatively little attenuation as a coin passes the coil. This means that the sensing circuit can be operated at low current without risking disappearance of the signal upon arrival cf a coin. Because it is the frequency of the signal which is used for detecting coin arrival, the relatively small change in amplitude does not detrimentally affect the sensitivity of the circuit. In addition, it has been found that in using the coil for diameter measurement, and arranging for there to be a coil on only one side of the coin path, fairly good discrimination can be achieved even with the sensing circuit operating at a low current.
- Preferably, a diameter-testing inductance, which may be the arrival sensor and which may be formed of a printed circuit, has a height which is substantially equal to its width. The overall shape of the inductance may be substantially square, or preferably circular. Preferably, the lower edge of the inductance is at or slightly below the bottom of the surface on which the coin rests as it passes the inductance.
- The maximum area of the inductance covered by a coin as it passes the inductance will depend on the coin diameter. Better discrimination can be achieved in this way, in which the area covered increases with the square of the diameter, than in an arrangement in which the inductance is elongate so that the length covered varies in proportion to the diameter.
- Preferably, the coin validator does not normalise the speed of coins delivered to a sensing station thereof, and has means responsive to a value indicative of the speed at which a coin is travelling through said sensing station for providing a signal indicating that the coin is not acceptable in response to determining that the coin has travelled too fast through the sensing station.
- The coin speed may be detected by measuring the interval between the coin passing two separate sensors and/or by measuring the rate of change of an output signal of a single sensor. Such an arrangement is particularly valuable in small coin validators where the distance between a coin entry slot and the coin sensors is short and therefore there is severe risk that the coin's motion when it reaches the sensor will not have stabilised to such an extent as to ensure accurate test results.
- US-A-3797628 discloses a coin validator in which token velocity is measured in order to determine whether a coin is acceptable. However, this is concerned with a different type of validator, in which the velocity of an inserted coin is normalised and then altered in accordance with the properties of the coin, so that the velocity measurement is in effect a test of the coin, rather than a test of whether the coin's flight is suitable for validation.
- Arrangements embodying the invention will now be described by way of example with reference to the accompanying drawings, in which:
- Fig. 1 schematically illustrates a coin passageway of a coin validator in accordance with the invention;
- Fig. 2 is a schematic circuit diagram of the coin validator;
- Fig. 3 is a circuit diagram of an arrival sensor of the validator;
- Fig. 4 is a circuit diagram of a material sensor in a modified embodiment of the validator;
- Fig. 5 is a schematic diagram of the circuit of the modified embodiment; and
- Figs. 6A and 6B are views of opposite sides of a printed circuit board carrying a testing coil used in each embodiment of the validator.
- Referring to Figs. 1 and 2, the
validator 2 has amain processor 4 which uses an arrival/diameter sensing circuit 6 and a material/thickness sensing circuit 8 for detecting the arrival of coins and for testing those coins and providing signals indicating whether a coin is genuine, and if so the type of the coin. - The arrival/
diameter sensing circuit 6 has asensing coil 10 connected in an oscillator circuit to be described in more detail subsequently. - The
coil 10 is situated at one side of acoin passageway 7. Thepassageway 7 is inclined and canted so that coins, such as that shown at 9, travel down thepassageway 7 in the direction A with their faces in contact with the side of the passageway on which thecoil 10 is located. Thecircuit 6 is so arranged that the signal appearing at theoutput 12 of thecircuit 6 has a frequency which alters as a coin passes thecoil 10, and which peaks at a level predominantly dependent upon the diameter of the coin. - The material/thickness sensing circuit 8 has a
coil 14 disposed at the opposite side of thecoin passageway 7 from thecoil 10. Thecoil 14 is connected in an oscillator circuit, and the circuit is so arranged that the signal appearing at theoutput terminal 16 is attenuated in response to a coin passing thecoil 14. The peak level of attenuation is predominently dependent upon the material from which the coin is made, and the thickness of the coin. Because the coin contacts the side of thepassageway 7 opposite to that on which thecoil 14 is located, the spacing of the coin from the coil will depend upon coin thickness, so that it is ensured that this will have a significant effect on the output of circuit 8. - The
processor 4 is a CMOS 8048 (or CMOS 8049) microprocessor. This has terminals P1, P2, P3, P4 and P5, which can be used as, respectively, a clock output terminal, an interrupt input terminal, a reset input terminal, an input/output terminal and a testable input terminal. There are also address/data bus terminals D. The remaining terminals referred to below are further input/output terminals which, unlike the terminal P4 which is used at different times as both an input and an output, are only required to perform a single input or output function in the particular circuit shown. Theprocessor 4 also has power supply terminals, clock input terminals etc. which are not shown in Fig. 2. - The
processor 4 has in its instruction set a HALT instruction, which when executed causes the processor to enter a quiescent state, in which no processing operations are carried out and the power consumption is substantially reduced. The processor can be switched back to an active state by a signal on the interrupt terminal P2. - The validator is installed in a pay telephone. Under normal circumstances the entire validator is switched off. When the handset is lifted, parts of the validator circuit, including the
processor 4 and arrival/diameter sensing circuit 6, but excluding the material/thickness sensing circuit 8, are switched on. - The
processor 4 then executes an initialisation routine, following which a HALT instruction is executed so that the processor enters a quiescent state. - The oscillations appearing at the
output terminal 12 of the arrival/diameter sensing circuit 6 are delivered viagates clock input 22 of acounter 24. The counter has output terminals C1 to C10. The counter counts the pulses until a signal appears at count output C10. This signal is delivered to the interrupt terminal P2 of theprocessor 4 in order to cause the processor to enter its active state. The processor then proceeds to issue on line 26 a clear signal which is delivered to theclear terminal 28 of thecounter 24. The processor also delivers on line 30 a signal for closing thegate 18. - The
processor 4 then temporarily opens thegate 18 for a predetermined duration. Thecounter 24 is thus caused to count the pulses appearing at theoutput terminal 12 of thecircuit 6. The final count, which appears at the count terminals C1 to C8, is noted by theprocessor 4 which has input/output terminals connected to those count terminals, before thecounter 24 is cleared by the processor. - The
processor 4 has a memory into which the count is stored, the arrangement being such that the memory always stores the previous count measured in this way. The processor determines that a coin has arrived at thecoil 10 if the second count exceeds the first by more than a predetermined number. Thus, a coin is detected in response to an increasing frequency appearing at theoutput terminal 12. - Assuming that a coin has not been detected, the
processor 4, after clearing thecounter 24, opens thegate 18 and executes the HALT instruction. Theprocessor 4 will then adopt its quiescent state until a signal appears once more at the count terminal C10. - The processor is thus regularly caused to enter its active state in order to determine whether or not a coin has arrived, and if not the processor re-enters its quiescent state. This may occur at intervals of, for example, 5 milliseconds, the processor being active for a period of less than 1 millisecond during each of these intervals. The average current consumption of the
processor 4 is thus low. - Assuming that the arrival of a coin is detected, the
processor 4 then continues to sample the frequency of the signal appearing at the terminal 12. The frequency continuously increases until a peak is reached, following which the frequency decreases until an idling level is reached, after the coin has left the coil. Theprocessor 4 recognises and stores the peak and idle levels, and thereafter calculates the ratio of these two levels in order to produce a diameter-indicating value. - At some stage, in response to detecting the arrival of a coin, the processor issues on line 32 a signal for operating a
power switch 34. This causes the power supply to be connected to the material/thickness sensor circuit 8. - The
processor 4 may be arranged to switch on the material/thickness sensor circuit 8 immediately after the detection of the arrival of a coin to ensure that the operation of circuit 8 has stabilised by the time the coin reachescoil 14. Alternatively, to conserve power, theprocessor 4 may be arranged to switch on the circuit 8 after detection of the peak in the output frequency of the signal atterminal 12, or possibly when theprocessor 4 has detected that the frequency has dropped to an idling level. - As a further alternative, the
processor 4 may be arranged to check that the diameter value is appropriate for a genuine coin of a denomination which the validator is arranged to accept before switching on the circuit 8. In this way, the circuit 8 will not be operated unless the coin has an acceptable diameter, and thereby power consumption is further reduced. - Once the diameter value has been calculated and the circuit 8 switched on, the
processor 4 issues a signal online 30 to close thegate 18, so that no more pulses from thecircuit 6 can reach thecounter 24. The counter is cleared, and the processor issues a signal on line 36 to open agate 38. This permits the gate to pass pulses from the terminal P1 via thegate 20 to theclock input terminal 22 of thecounter 24. - The
counter 24 thus counts up at a constant, predetermined rate. The count terminals C1 to C8 are connected via resistors R1 to R8 to respective points on a series resistor network R9 to R16 coupled between ground and oneinput 40 of acomparator 42. The other input.44 of thecomparator 42 is connected to theoutput terminal 16 of the circuit 8. - The resistors R1 to R16 act as potential dividers in such a manner that a signal at any one of the count output terminals C1 to C8 will produce, at the
input terminal 40 of thecomparator 42, a voltage corresponding to the respective count terminal. The effect of this is to cause the voltage at the terminal 40 to increase progressively in a stepwise manner as the count reached by thecounter 24 increases. The resistors are of close tolerance to ensure an even distribution of the voltages produced as the count increases. - After the processor issues the signal from terminal P4 which opens the
gate 38, the terminal is switched so that it now behaves as an input terminal. As the voltage at theinput terminal 40 of thecomparator 42 increases, it will eventually rise past the voltage at terminal 44 from the circuit 8. At this time, the output ofcomparator 42 will switch logic levels, thus closinggate 38 and preventing further pulses from reaching thecounter 24. This change in logic levels will also be sent to terminal P4 of theprocessor 4, which is detected by theprocessor 4 and used to indicate that the count output terminals C1 to C8 should be read. The count will be a digital representation of the analog voltage atterminal 16 of the circuit 8. - The
counter 24 is then cleared, the terminal P4 switched to behave as an output terminal, and thegate 38 re-opened so as to permit theprocessor 4 to take a further measurement of the output signal appearing atterminal 16 of the circuit 8. - The
comparator 42 has an open-collector output so that this and the terminal P4 can be directly connected to thegate 38, whereby each can controlgate 38, without interfering with each other. - The
processor 4 repeatedly measures the output appearing atterminal 16, and determines from these measurements the idle value. This is done before the coin reaches thesensor coil 14, and may be initiated by thecircuit 6 sensing the departure of the coin fromcoil 10. Then as the attenuation increases during the movement of the coin past the sensor, the peak value of the signal is determined. This is preferably achieved by storing successive measurement values. The processor detects when these values alter in such a manner as to indicate that the attenuation is decreasing due to the coin leaving the sensor. The processor then averages the stored values, preferably ignoring the more recent measurements so that the values used represent measurements taken when the coin was substantially at the mid-point of its travel past the sensor. For example, the processor may be arranged to take the average of the first, say, four of the last twelve measurements. Of course, instead of taking an average measurement by summing a predetermined number of values and then dividing by that number, so as to compare the resulting value with a stored range, the processor could simply sum the values without dividing the result; the stored ranges would be correspondingly greater. - The ratio of the idle and peak values is determined in order to produce a thickness/material-indicating value. The idle value is measured before the peak so that the decision as to whether an accept/reject gate should be opened can be made very soon after the peak has been reached, and therefore little space is required between the
coil 14 and this gate. - At the end of the thickness/material testing operation, the circuit 8 is switched off, the
counter 24 is cleared and thegate 18 is re-opened to allow the pulses appearing atoutput terminal 12 ofcircuit 6 to reach thecounter 24. - For each of the denominations of coins which the
validator 2 is designed to accept, theprocessor 4 stores information defining a diameter range and a material/thickness range. For example, theprocessor 4 may store upper and lower limits of the respective ranges, or alternatively may store a single value from which the processor can calculate, using a stored or predetermined tolerance, the appropriate range. - The
processor 4 compares the two measurements, i.e. the diameter value and the thickness/material value, with the ranges for the respective coins, and determines that a valid coin of a particular denomination has been received if both values fall within the appropriate ranges for that denomination. In that case, theprocessor 4 produces on one or both ofdata lines 46 an ACCEPT signal, and on lines 48 a binary signal indicating the denomination of the coin. - The
coin validator 2 is intended for installation in various types of machines, e.g. gaming machines. In some of these, it is desired that the machine be capable of accepting a first range of coins (e.g. 5p, 10p, 20p and 50p U.K. denomination coins), and in other machines a different range (e.g. 10p, 20p, 50p and £1 coins). To cater for this without requiring different types of validator to be manufactured, the validator is arranged to recognise all five coins and generate ACCEPT signals onlines 46 in accordance with the range of coin denominations within which a received coin lies. Thus, if the denomination of a received coin falls within both ranges (e.g. for 10p, 20p and 50p coins) an ACCEPT signal is generated on bothlines 46, and the coin denomination indicated by the data onlines 48. If the coin denomination lies in only one range (e.g. 5p), then only one of the lines 46 (corresponding to that range of denomin ations) carries the ACCEPT signal while thelines 48 carry data representing the denomination 5p. When a coin denomination which belongs only to the other range is received (e.g. a £1 coin), the same data onlines 48 can be generated, but this time the ACCEPT signal is generated on the other of thelines 46. - Accordingly, the same validator can be installed in any of the above types of machines, and in each case it is merely necessary to select which of the
lines 46 is to be used in accordance with the range of denominations which the machine is intended to accept. - There is a danger that the
processor 4 may "hang-up", i.e. may cease to operate properly, for example due to electrical noise or interference. To avoid problems caused by this faulty operation, thevalidator 2 has a reset pulse generator 50, which produces a pulse of predetermined length to reset theprocessor 4 in the event that any one of three conditions indicative of "hang-up" occurs. - As mentioned above, the output of counter terminal C10 is used to deliver a signal to interrupt terminal P2 of
processor 4, which causes the processor to issue a signal online 26 to clear thecounter 24. If this does not occur, due to faulty operation of theprocessor 4, the counter will not be cleared and will continue to count in response to pulses from thecircuit 6. Eventually, an output signal will appear at terminal C9 of thecounter 24, and the simultaneous appearance of signals at terminals C9 and C10 will be detected by agate 52, which will deliver an activating signal via agate 54 to the circuit 50 to cause resetting of theprocessor 4. - The
gate 54 has two further inputs connected torespective detection circuits Circuit 56 is connected to theclear terminal 28 of thecounter 24, so that if after issuing a signal to clear the counter the processor suddenly begins to behave incorrectly, the signal at theclear input terminal 28 will persist longer than it should, and this will be detected by thecircuit 56 which will issue asignal view gate 54 to circuit 50 to cause resetting of theprocessor 4. - The
circuit 58 has its input connected to theline 30 which carries the signal issued by theprocessor 4 to close thegate 18. The longest time for which thegate 28 is closed occurs when the processor is measuring the output of circuit 8. The delay ofcircuit 58 is set to be longer than this time. If theprocessor 4 begins to behave incorrectly during the thickness/material measuring operation, and thegate 18 thus remains closed, this will be detected by thecircuit 58 and cause resetting of the processor. - Even if the
processor 4 begins to behave improperly, it may nevertheless execute an interrupt routine, initiated by the signal delivered to terminal P2, in a correct manner. To detect this situation, theprocessor 4 is arranged to set a number of internal flags while executing the arrival detection routine. During the interrupt routine, theprocessor 4 checks to see that these flags are set. If they are not, because the main routine was not being executed properly, theprocessor 4 executes an instruction which causes it to be reset. - The validator is preferably made in such a way that the coin measurements which are made produce fairly predictable results for given denominations, so that the parameter ranges stored by the
processor 4 do not have to be specially worked out for each validator. However, to accommodate slight variations between validators, and changes in a particular validator due to ageing or drift, thesensing circuits 6 and 8 can be adjusted in respect of frequency and/or gain to vary their outputs. - To facilitate the making of adjustments, the
processor 4 can be switched into a test mode by connecting alink 59 between a power supply rail and the testable input terminal P5, which terminal is normally held at a low potential by a resistor R17 connected to ground. At the same time, the operator connects a device to the data lines D to display the potentials on these lines. - After switching the validator into the test mode, the operator inserts a coin of a particular denomination (e.g. 10p), and determines what signals are produced on the data lines 46 and 48 in response thereto. The inserted coin is preferably specially selected so that its properties are of an average value with respect to the normal variations expected of coins of that denomination.
- The
processor 4 operates as described up to and including the obtaining of digital values representing the measurements made by thesensing circuits 6 and 8. At that time the processor checks the terminal P5, and if this is found to be high the processor then executes a test routine instead of continuing with the validation operations described above. - In the test routine, the values derived from the
sensing circuits 6 and 8 are compared with a special set of "test ranges", instead of with the normal acceptability ranges. These test ranges correspond to the ranges used to determine whether an acceptable coin of the particular denomination (e.g. 10p) has been received, except that they are narrower than the acceptability ranges. - In the test mode, the processor's output on
data lines output lines sensing circuit 6 exceeds or falls below the respective range, thelines 46 are caused to carry a binary value of "10" or "01", respectively. Similarly, if the value derived from sensing circuit 8 exceeds or falls below its respective test range, the value produced onlines 48 is "10" or "01", respectively. An output value of "0000" onlines sensing circuits 6 and 8 produce incorrect values which are clearly not due merely to poor adjustment (e.g. values resulting from two coins being detected at the same time, a poor coin flight path, etc.) so that the operator will be able to take appropriate action. - Referring now to Fig. 3, the arrival/
diameter sensing circuit 6 comprises thecoil 10 connected in a Colpitt's oscillator circuit. In the particular configuration used here, an amplifier formed by atransistor 60 has a feedback loop including thecoil 10 connected between its collector and base. Thecoil 10 is connected in series with an adjustment circuit comprising variable resistor 61 connected in parallel withinductance 63. -
Capacitors components -
Resistors 66, 68 and 70 are provided for biasing thetransistor 60 into conduction. The load on thetransistor 60 is distributed between a collector impedance (formed by a resistance RL and an inductance LL) and the resonant circuit formed by thecomponents - Thus, the output voltage appearing across the
capacitor 62 is dependent to a large extent on the fixed impedance RL and LL. Thus, although the passage of a coin in proximity to thecoil 10 will cause some attenuation of this voltage, the degree of attenuation will be relatively small, because the load impedance does not change, compared with a circuit such as those used in the above-mentioned British Patent Specification No. 2093620, in which the coil is connected to the collector current path and therefore has a very substantial effect on the output voltage. The incorporation of inductance LL increases the stability of the output voltage with changes in frequency. - Accordingly, the
circuit 6 can be arranged so that it normally consumes a low level of current, but nevertheless will provide an output signal which will not disappear even when a coin is in close proximity to thecoil 10. This makes the circuit particularly suitable for use as an arrival sensing circuit. To reduce cost and power consumption, the circuit is, as mentioned above, also used for measuring purposes. It has been found that if thecoil 10 is suitably arranged for diameter measurement, and the frequency of the output rather than the amplitude is used for measurement purposes, good discrimination can be achieved with the same low operating current as is used for arrival sensing. - A modified version of the above embodiment will now be described with particular reference to Figures 4 and 5. This embodiment operates in a similar manner to the one described above, and similar reference numbers will be used for similar parts, except for the points set out below.
- In the previously described embodiment, the sensing circuit 8 produced an output whose amplitude was sensed in order to provide an indication of the material and thickness of the coin. In the embodiment of Figures 4 and 5, the sensor is used for providing an output which is predominantly dependent upon the material of the coin, and somewhat less dependent upon thickness. In this case there are two
coils - Figure 4 shows the circuit 8, which is additionally suitable for use in the first-described embodiment. The circuit has a standard oscillator configuration, using a
transistor 100. The twocoils variable inductance 102. The inductances are connected in the collector path of thetransistor 100. The emitter path includes avariable resistor 104. - The output of the circuit 8 is indicated at 106, and is taken from the collector of
transistor 100. As a coin passes between thesensors - These parameters can be adjusted using the
variable inductance 102 and thevariable resistor 104. Preferably the frequency is adjusted first using thevariable inductance 102, as this will also have an effect on amplitude. - Referring to Figure 5, in this embodiment the
microprocessor 4 is of the Motorola 6805 family. This has a plurality of ports which can be used as input or output terminals. In the arrangement shown, terminals I1 to I3 are used as input terminals, andterminals 01 to 011 are used as output terminals. - The microprocessor has an internal counter which can be clocked at regular intervals so that it acts as a timer the operation of which can be initiated or halted by the application of a signal to terminal T1. Alter natively, the counter can be used to count pulses appearing on terminal T1. This internal counter is used in place of the
counter 24 of Figure 2. - The
microprocessor 4 can operate aswitch 150 which selectively delivers the output pulses ofsensing circuit 6 to a divide-by-four circuit 152 formed of two flip-flops. The output of circuit 152 is delivered to the terminal T1. The internal counter can thus be used for counting pulses from thecircuit 6 and hence measuring the frequency of the output. The states of the flip-flops in circuit 152 are detected on input lines I2 and I3 so that two extra bits of resolution can be achieved. When counting is commenced, the circuit 152 is released from its set state by changing the signal appearing onoutput terminal 05. After the measuring operation, the circuit 152 is held in a set state which allows the input terminal T1 to receive other signals, as will be described. - In particular, the output of sensing circuit 8 is delivered via another microprocessor-controlled switch 154 to terminal T1 so that the frequency of this output can be measured. In this case the divide-by-four circuit 152 is not required as the
coils coil 10. - The output of the sensing circuit 8 is also delivered via a
rectifying circuit 156 to acomparator 158. Another input of thecomparator 158 is connected to a junction between a constantcurrent charging circuit 160 and acapacitor 162. The chargingcircuit 160 can be switched on or off by anoutput terminal 02 of themicroprocessor 4. - In operation, in order to measure the amplitude of the output of sensing circuit 8, the microprocessor switches on the charging
circuit 60 and at substantially the same time starts the internal counter, which is acting in its timer mode. This causes the voltage on thecapacitor 162 to rise linearly. As soon as this voltage equals that from the rectifyingcircuit 156, the output ofcomparator 158 switches polarity, which is detected at input terminal I1. The microprocessor senses this, and determines the count reached by the internal timer, which is digital representation of the amplitude of the output of sensing circuit 8. - The output of the
comparator 158 is delivered to the timer terminal T1 via a microprocessor-controlledswitch 164. This is to ensure that the operation of the timer is halted immediately the output of thecomparator 158 changes state; this avoids problems caused by the delay in the microprocessor first detecting the change in state at terminal I1 and then halting the timer. - Thus, the internal counter measures (a) frequency of output of
sensing circuit 6, (b) frequency of output of sensing circuit 8, and (c) amplitude of output of sensing circuit 8. - The circuit operates substantially as described with reference to Figure 2. However, after the coin starts to leave the
coil 10, themicroprocessor 4 first measures the amplitude of the output of sensing circuit 8, then measures its frequency, and then once more measures the amplitude. The two amplitude measurements are averaged to obtain the idle amplitude value. The frequency measurement takes place over a sufficiently long time that any slight fluctuations in frequency do not affect the result. - Subsequently, amplitude measurements are repeatedly taken. As the coin enters the space between
coils coils - This operation gives rise to three measurement values, each comprising the ratio of an idle value with the peak value, which are compared with respective ranges to determine whether the coin is valid, and if so the denomination of the coin.
- If the coin is valid, an ACCEPT signal is delivered on
output terminal 07, and the denomination of the coin is indicated by the signals onlines - The
microprocessor 4 also times the interval between the coin arriving at thecoil 10 and departing from thecoils sensing circuit 6, and successive values of the amplitude of sensing circuit 8, and if either of these is altering too rapidly the coin is rejected on the basis that it is travelling either too fast or in an unstable manner. - When an operator wishes to test the operation of the validator, he operates a switch or connects a link to issue a pulse to an interrupt terminal INT of the microprocessor 4 (instead of using a test terminal T1 as in Fig. 2). This causes the microprocessor to execute an interrupt routine which results in signals being generated on a serial
data output line 010 in response to a coin passing thecoils output line 010 indicates what adjustments need to be made to thesensing circuits 6 and 8. - The operator has a test device connected to receive the data from
output terminal 010 and clock pulses fromoutput terminal 011. The device includes logic circuitry which decodes the data so as to provide a display indicating whether and in which manner any of the components 61 (Fig. 3), 102 and 104 (Fig. 4) need adjustment. - The
switches - Referring to Figs. 6A and 6B, in conjunction with Fig. 1, a preferred form of the
coil 10 will now be described. The coil is formed by a printed circuit etched on both sides of a double-sided printedcircuit board 80. Fig. 6A shows theside 82 of theboard 80 which in use is more closely adjacent the coin path, and Fig. 6B shows theopposite side 84. Theboard 82 is located in a plane parallel to the side walls of thepassageway 7. - On each side, the printed circuit board has been etched to form a spiral conductive pattern having an overall substantially circular configuration.
- Referring to Fig. 6A, the
side 82 carries twoterminal portions 86 and 88. The conductive path starts from the terminal portion 86 and then spirals inwardly to aninner contact portion 94. - The
terminal portions 86 and 88 are positioned directly opposite corresponding terminal portions on theside 84 which are respectively labelled 86′ and 88′, and may if desired be connected thereto by respective plated through-holes. Theinner contact portion 94 is connected via a plated through-hole to acorresponding contact portion 94′ on theside 84. From there, the printed circuit pattern spirals outwardly toterminal portion 88′. - Thus, the
terminal portions 86 and 88′ form the opposite ends of thecoil 10. In use, the field created by the portion of thecoil 10 onside 82 will extend in the same direction as the field produced by the part of the coil on theside 84. - The respective parts of the
coil 10 on the opposite sides of theboard 80 can be positioned very accurately with respect to the coin path, so that there is good consistency in the measurements produced by thecoil 10 from validator to validator. Thus, only minor adjustments using the variable resistor 61 of Fig. 3 are needed. - The bottom edge of the
coil 10 is located at or preferably slightly below the bottom of the coin path so that if a coin passing thecoil 10 tends to bounce there is little or no effect upon the coil area covered by the coin and hence upon the measured value. - The term "coin" has been used herein to cover not only genuine coins but also non-genuine coins or other items which might be received by the validator.
Claims (15)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8329533 | 1983-11-04 | ||
GB838329533A GB8329533D0 (en) | 1983-11-04 | 1983-11-04 | Coin validators |
GB8405721 | 1984-03-05 | ||
GB848405721A GB8405721D0 (en) | 1983-11-04 | 1984-03-05 | Coin validators |
Related Parent Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP84307619.1 Division | 1984-11-05 | ||
EP19840307619 Division EP0146251B1 (en) | 1983-11-04 | 1984-11-05 | Coin validators |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0308996A2 true EP0308996A2 (en) | 1989-03-29 |
EP0308996A3 EP0308996A3 (en) | 1989-05-17 |
Family
ID=26286975
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19840307619 Expired - Lifetime EP0146251B1 (en) | 1983-11-04 | 1984-11-05 | Coin validators |
EP88117268A Expired - Lifetime EP0308997B1 (en) | 1983-11-04 | 1984-11-05 | Coin validators |
EP88117267A Withdrawn EP0308996A3 (en) | 1983-11-04 | 1984-11-05 | Coin validators |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19840307619 Expired - Lifetime EP0146251B1 (en) | 1983-11-04 | 1984-11-05 | Coin validators |
EP88117268A Expired - Lifetime EP0308997B1 (en) | 1983-11-04 | 1984-11-05 | Coin validators |
Country Status (6)
Country | Link |
---|---|
EP (3) | EP0146251B1 (en) |
DE (2) | DE3486213T2 (en) |
GB (1) | GB2151062B (en) |
HK (1) | HK74297A (en) |
SG (1) | SG32491G (en) |
WO (1) | WO1985002047A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0607624A1 (en) * | 1993-01-21 | 1994-07-27 | National Rejectors Inc. GmbH | Electrical switch-on sensor for battery powered coin tester |
Families Citing this family (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB8509609D0 (en) * | 1985-04-15 | 1985-05-22 | Coin Controls | Discriminating between different metallic articles |
JPH0546127Y2 (en) * | 1986-12-29 | 1993-12-01 | ||
JPH0534060Y2 (en) * | 1987-10-08 | 1993-08-30 | ||
GB8814980D0 (en) * | 1988-06-23 | 1988-07-27 | Ace Coin Equip | Coin checking device |
JPH0673151B2 (en) * | 1988-12-14 | 1994-09-14 | サンデン株式会社 | Coin receiving device for vending machines |
IT1232019B (en) * | 1989-02-23 | 1992-01-23 | Urmet Spa | FINALIZATION FOR COIN SELECTORS |
IT1232018B (en) * | 1989-02-23 | 1992-01-23 | Urmet Spa | PERFECTED COIN SELECTOR |
ES1011067Y (en) * | 1989-07-12 | 1992-04-01 | Jofemar, S.A. | IMPROVEMENTS IN THE READING OF MAGNETIC SENSORS IN COIN SELECTORS. |
GB2234619B (en) * | 1989-07-28 | 1993-04-14 | Mars Inc | Coin validators |
DE4025328A1 (en) * | 1990-08-10 | 1992-02-13 | Nat Rejectors Gmbh | ELECTRONIC COIN CHECKER |
WO1992009057A1 (en) * | 1990-11-07 | 1992-05-29 | Mars Incorporated | Method and apparatus for a low-power, battery-powered vending and dispensing apparatus |
US5244070A (en) * | 1992-03-04 | 1993-09-14 | Duncan Industries Parking Control Systems Corp. | Dual coil coin sensing apparatus |
ATE170312T1 (en) * | 1992-06-03 | 1998-09-15 | Landis & Gyr Tech Innovat | COIN DETECTOR |
RO118233B1 (en) * | 1992-08-13 | 2003-03-28 | Landis & Gyr Business Suport Ag | Method for calibrating the coin checkers and coin checker |
DK0704825T3 (en) * | 1994-09-21 | 1998-08-10 | Ip Tpg Holdco S O R L | Device for testing the authenticity of coins, game marks or other flat metallic objects |
GB2323200B (en) | 1997-02-24 | 2001-02-28 | Mars Inc | Coin validator |
GB2401980B (en) * | 2003-03-14 | 2006-02-15 | Int Currency Tech | Power control circuit for use in a vending machine |
US20070007104A1 (en) * | 2005-06-22 | 2007-01-11 | Piccirillo James S | Electronic coin recognition system |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3797628A (en) * | 1972-03-17 | 1974-03-19 | Little Inc A | Device and method for testing coins employing velocity determining means |
US3901368A (en) * | 1974-03-11 | 1975-08-26 | Lance T Klinger | Coin acceptor/rejector |
US3952851A (en) * | 1973-05-18 | 1976-04-27 | Mars, Inc. | Coin selection method and apparatus |
GB2045500A (en) * | 1979-03-12 | 1980-10-29 | Matsushita Electric Ind Co Ltd | Coin selector for vending machine |
EP0058094A1 (en) * | 1981-02-11 | 1982-08-18 | Mars Incorporated | Improvements in and relating to apparatus for checking the validity of coins |
EP0062411A2 (en) * | 1981-03-19 | 1982-10-13 | LANDIS & GYR COMMUNICATIONS (U.K.) LTD. | Method and apparatus for coin validation |
US4381552A (en) * | 1978-12-08 | 1983-04-26 | Motorola Inc. | Stanby mode controller utilizing microprocessor |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1465636A (en) * | 1965-12-01 | 1967-01-13 | Signaux Entr Electriques | Controller of moving metal bodies |
GB1217066A (en) * | 1967-05-12 | 1970-12-23 | Tateisi Electronics Company | Coin detecting system |
US3682286A (en) * | 1969-07-19 | 1972-08-08 | Georg Prumm | Method for electronically checking coins |
DE2146184A1 (en) * | 1971-09-15 | 1973-03-22 | Standard Elektrik Lorenz Ag | COIN VALIDATOR |
FR2212589B1 (en) * | 1972-12-29 | 1976-10-29 | Satmam | |
CH580811A5 (en) * | 1975-01-14 | 1976-10-15 | Sodeco Compteurs De Geneve | |
JPS5611181Y2 (en) * | 1975-12-02 | 1981-03-13 | ||
US4108296A (en) * | 1976-04-08 | 1978-08-22 | Nippon Coinco Co., Ltd. | Coin receiving apparatus for a vending machine |
GR69124B (en) * | 1980-02-06 | 1982-05-03 | Mars Inc | |
GB2084310B (en) * | 1980-09-19 | 1984-03-14 | Mitchell Douglas Allison | A solid fuel effect gas fire |
US4359148A (en) * | 1980-10-28 | 1982-11-16 | Third Wave Electronics Company, Inc. | Coin acceptor or rejector |
GB2094008B (en) * | 1981-02-11 | 1985-02-13 | Mars Inc | Improvements in and relating to apparatus for checking the validity of coins |
GB2118344A (en) * | 1982-02-12 | 1983-10-26 | Mars Inc | Coin testing apparatus |
JPS59111587A (en) * | 1982-12-16 | 1984-06-27 | ロ−レルバンクマシン株式会社 | Money inspector for coin processing machine |
-
1984
- 1984-11-05 GB GB8427935A patent/GB2151062B/en not_active Expired
- 1984-11-05 EP EP19840307619 patent/EP0146251B1/en not_active Expired - Lifetime
- 1984-11-05 EP EP88117268A patent/EP0308997B1/en not_active Expired - Lifetime
- 1984-11-05 EP EP88117267A patent/EP0308996A3/en not_active Withdrawn
- 1984-11-05 DE DE19843486213 patent/DE3486213T2/en not_active Expired - Lifetime
- 1984-11-05 WO PCT/GB1984/000381 patent/WO1985002047A1/en unknown
- 1984-11-05 DE DE19843485866 patent/DE3485866T2/en not_active Expired - Lifetime
-
1991
- 1991-05-02 SG SG32491A patent/SG32491G/en unknown
-
1997
- 1997-06-05 HK HK74297A patent/HK74297A/en not_active IP Right Cessation
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3797628A (en) * | 1972-03-17 | 1974-03-19 | Little Inc A | Device and method for testing coins employing velocity determining means |
US3952851A (en) * | 1973-05-18 | 1976-04-27 | Mars, Inc. | Coin selection method and apparatus |
US3901368A (en) * | 1974-03-11 | 1975-08-26 | Lance T Klinger | Coin acceptor/rejector |
US4381552A (en) * | 1978-12-08 | 1983-04-26 | Motorola Inc. | Stanby mode controller utilizing microprocessor |
GB2045500A (en) * | 1979-03-12 | 1980-10-29 | Matsushita Electric Ind Co Ltd | Coin selector for vending machine |
EP0058094A1 (en) * | 1981-02-11 | 1982-08-18 | Mars Incorporated | Improvements in and relating to apparatus for checking the validity of coins |
EP0062411A2 (en) * | 1981-03-19 | 1982-10-13 | LANDIS & GYR COMMUNICATIONS (U.K.) LTD. | Method and apparatus for coin validation |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0607624A1 (en) * | 1993-01-21 | 1994-07-27 | National Rejectors Inc. GmbH | Electrical switch-on sensor for battery powered coin tester |
US5454463A (en) * | 1993-01-21 | 1995-10-03 | Meyer; Wilfried | Electric starting sensor for battery-operated coin acceptors |
Also Published As
Publication number | Publication date |
---|---|
HK74297A (en) | 1997-06-13 |
DE3486213T2 (en) | 1994-01-13 |
EP0308997A2 (en) | 1989-03-29 |
SG32491G (en) | 1991-06-21 |
GB2151062A (en) | 1985-07-10 |
GB2151062B (en) | 1988-06-29 |
DE3486213D1 (en) | 1993-10-28 |
EP0146251A1 (en) | 1985-06-26 |
EP0308997B1 (en) | 1993-09-22 |
WO1985002047A1 (en) | 1985-05-09 |
DE3485866D1 (en) | 1992-09-17 |
EP0308996A3 (en) | 1989-05-17 |
GB8427935D0 (en) | 1984-12-12 |
DE3485866T2 (en) | 1992-12-10 |
EP0146251B1 (en) | 1992-08-12 |
EP0308997A3 (en) | 1989-05-17 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0308996A2 (en) | Coin validators | |
US4538719A (en) | Electronic coin acceptor | |
EP0304535B1 (en) | Improvements in and relating to apparatus for checking the validity of coins | |
EP0155126B1 (en) | Self tuning coin recognition system | |
US4184366A (en) | Coin testing apparatus | |
US4254857A (en) | Detection device | |
GB2143982A (en) | Checking coins | |
CA1153806A (en) | Coin acceptor apparatus | |
EP0203702B1 (en) | Moving coin validation | |
US5460256A (en) | Coin sensor device | |
US4385684A (en) | Coin selection device | |
EP1012796B1 (en) | Method and apparatus for validating coins | |
EP0316308A1 (en) | Coin detection device | |
CA2184147C (en) | Coin detection device and associated method | |
US6223878B1 (en) | Method and apparatus for validating coins | |
JP2817021B2 (en) | Medal detector for gaming machines | |
JPH0117195B2 (en) | ||
JPS6013517B2 (en) | coin inspection device | |
JPS6129040B2 (en) | ||
IES62628B2 (en) | Method for fecognizing coins |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AC | Divisional application: reference to earlier application |
Ref document number: 146251 Country of ref document: EP |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
17P | Request for examination filed |
Effective date: 19891115 |
|
17Q | First examination report despatched |
Effective date: 19911015 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 19920226 |