JP2002352295A - Coin-like object detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coin-like object detection sensor that can easily extend the detection distance by enhancement of receiving sensitivity and surely detect coin-like objects such as medals or coins circularly formed by metal plate, which move on a path when a sensor is constituted by using two coils. SOLUTION: In the coin-like object detection sensor to detect metal coin-like objects to move on the path, it is characterized by oppositely arranging a transmission coil to be a generation source of a magnetic flux and a reception coil to generate induction output by an influence of the magnetic flux by sandwiching the path, intermittently exciting the transmission coil by providing an intermittent drive means to intermittently drive excitation of the transmission coil and detecting move of the coin-like object on the path between both the coils by size of the induction output of the reception coil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coin-shaped object detecting sensor for detecting a coin-shaped object formed in a circular shape on a metal plate, such as a medal or a coin.

[0002]

2. Description of the Related Art For example, in a slot machine (pachislot) used as one of popular entertainment, a sensor for detecting the insertion of medals is provided inside an insertion slot for inserting medals.

If this sensor is constituted by a sensor using light such as a photoelectric sensor, for example, when a slot machine is purchased and the mechanical structure of the medal slot is disassembled and examined for a fraudulent purpose, an optical path is formed in the passage. Since there is a slit for projecting light, the discovery of this slit reveals the presence of a sensor, and this sensor has the problem of being targeted for fraud,
Further, since the type of the sensor is determined to be a photoelectric sensor, a counterfeit coin may simply be provided with a function of blocking an optical path, and thus has a problem that it is easy to make.

As described above, there is a method of detecting whether or not a medal has passed between two coils when it is determined that a sensor using light is inappropriate.

[0005] The detection sensor system using the two coils includes, for example, a first system in which a pair of coils of a general high-frequency oscillation type proximity switch are arranged facing each other; As a method, the mutual inductance between the coils is detected by using a change due to the approach of a metal, and as a third method, the magnetic flux of one of the coils that is oscillated in a steady state is received by the other coil, When a metal exists at a position where the transmission and reception of magnetic flux between the coils is shielded, there is a method of detecting by utilizing a change in transmission (induction) output generated in the reception coil.

However, as described above, when a medal is detected, a sufficient detection distance is required because the width of the path for rolling the medal is designed to be relatively wide due to the thickness of the medal.

In order to satisfy the above-mentioned requirement, that is, to increase the detection distance, the first and second methods detect the current by utilizing the impedance change of the coil. For the metal to be detected, it is necessary to set the oscillation frequency and current at which the change can be obtained most effectively to a specific value. With the increase of the distance, the detection distance cannot be easily expanded.

Further, in the above-mentioned third method, it is theoretically possible to increase the magnetic flux generated by the coil on the transmitting side, but it substantially leads to an increase in power consumption.
It cannot be adapted to the device actually used and cannot be implemented.

[0009]

SUMMARY OF THE INVENTION According to the present invention, when a coin-shaped sensor formed of a metal plate in a circular shape such as a medal or a coin by using two coils is used, the receiving sensitivity is improved. It is an object of the present invention to provide a coin-shaped object detection sensor which can easily increase the detection distance and can surely detect a coin-shaped object moving in a passage.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a coin-shaped object detecting sensor for detecting a metal coin-shaped object moving in a passage, comprising: a first coil (transmitting coil) serving as a magnetic flux generating source; A second coil (receiving coil) that generates an induced output under the influence of the magnetic flux is disposed to face the second coil (receiving coil) with the path interposed therebetween, and intermittent driving means for intermittent driving is provided to intermittently drive the first coil (transmitting coil). And a coil-like body detection sensor for detecting the movement of the coin-like body in the path between the two coils based on the magnitude of the induced output of the second coil (receiving coil).

That is, the first coil (transmitting coil) of the magnetic flux generating source is intermittently driven to be excited. In this excitation, the coil exciting current changes sharply at the rising and falling portions of the exciting oscillation of the coil. In this case, since the induced output of the second coil (receiving coil) increases in proportion to the amount of change in the exciting current, the rise of the induced output with respect to the rise of the excitation oscillation and the rise of the induced output with respect to the fall of the excitation oscillation are: The steeper the change, the larger the occurrence. This means that the reception sensitivity when there is no coin-shaped body between the first and second coils is increased, and the transmission / reception margin is improved, and the reception sensitivity is increased and the transmission / reception margin is improved. The detection distance (= distance between coils) can be increased.

In addition, when an induction output when the first coil (transmitting coil) is intermittently driven and a magnetic flux excited and oscillated by the second coil (receiving coil) is directly received is used as a comparison reference without a coin-shaped body. When the coin-shaped body interrupts the magnetic flux and the induced output of the second coil (receiving coil) in the interrupted state changes (for example, changes in a smaller direction) than the above-mentioned comparative reference induced output, the coin-shaped body Is detected.

Further, when the coin-shaped body blocks the magnetic flux of the first coil (transmitting coil), leakage corresponding to each state occurs in the blocking of the magnetic flux depending on the material and size of the coin-shaped body. In addition, a different induction output corresponding to the state of the coin-shaped body is also output to the induction output of the second coil (receiving coil) that receives the leakage of the magnetic flux. Therefore, by setting the above-mentioned comparison reference value in accordance with the state of the coin-shaped body and executing the comparison process, the size and material of the coin-shaped body can also be detected.

As an embodiment of the present invention, a plurality of the second coils (receiving coils) can be arranged to face the first coils (transmitting coils) along the moving direction of the coin-shaped body. With this configuration, the plurality of second coils (receiving coils) output detection outputs along the moving direction of the coin-shaped body, so that the moving direction of the coin-shaped body can be detected.

Of course, a second coil (receiver coil) can be arranged on each of both end faces of the first coil (transmitter coil). In this case, one first coil (transmitter coil) requires two coils. A coin-shaped object in the passage can be detected.

As an embodiment of the present invention, a plurality of receiving circuits each having a different discrimination reference value set are connected to the second coil, and a combination of detection and non-detection signals of these reception circuits is used. It is possible to determine the type of the coin, for example, its size and material.

As an embodiment of the present invention, a constant current source can be used as an electric energy supply source for intermittently driving the first coil (transmitting coil). In this case, the maximum value of the amplitude of the excitation oscillation generated in the first coil (transmitting coil) can be greatly changed irrespective of the power supply voltage, and this large change causes the second coil (receiving coil) on the receiving side to change. ), The transmission / reception margin is improved, and the detection distance (= inter-coil distance) can be further increased by the improvement.

According to an embodiment of the present invention, an intermittent signal width of an intermittent driving means for intermittently exciting the first coil (transmitting coil) includes an induced oscillation wave generated at the rise of the intermittent signal, and an intermittent signal. Can be set to a width that is superimposed and synthesized with the induced oscillation wave generated at the falling edge of.

Specifically, the second coil (receiving coil)
Is set to a time obtained by adding a half cycle to an integral multiple of the oscillation cycle determined by the resonance frequency of the second coil (receiving coil), the reception waveform generated at the rise of the above-described intermittent signal (pulse signal) and the intermittent signal Since the phase of the received waveform generated at the fall of the (pulse signal) matches, the superimposed synthesized wave (synthesized induced output) has the maximum amplitude. The receiving sensitivity of the (receiving coil) is further increased, the margin for transmission and reception is improved, and the detection distance can be made longer.

As an embodiment, a game medal detection sensor for detecting a game medal can be constituted by the coin-shaped body detection sensor described above.

[0021]

According to the present invention, the transmission / reception sensitivity of the first coil (transmission coil) and the second coil (reception coil) is improved, and the detection distance can be easily expanded.
The distance between the first coil (transmitting coil) and the second coil (receiving coil) can be set to a necessary and sufficient distance, and the passage width of the coin-shaped body is set to a necessary and sufficient width. Also, the coin-shaped body can be reliably detected.

Also, in this coin-shaped body detection sensor, the use of a coil, and the transmitting and receiving sides of both coils are, for example,
Since it can be used concealed with a material such as a synthetic resin plate, even if the passage is disassembled and the existence of the sensor is examined, there is no external object such as a slit that emits light like a photoelectric sensor. Can be made extremely difficult, and the sensor can be excluded from fraudulent objects. For example, even if the sensor is used as a sensor for detecting the insertion of a medal in a medal insertion slot of a gaming machine, its presence does not exist. Because it is unknown,
Has the effect of not being targeted for injustice.

Further, since a detection output can be obtained in accordance with the material and size of the coin-shaped body, it is possible to judge them, and it is also used for discrimination of coins (coins) and authenticity. be able to.

Further, since a plurality of second coils (receiving coils) are arranged opposite to the first coil (transmitting coil) along the moving direction of the coin-shaped body, the moving direction of the coin-shaped body is changed. Can be detected.

Of course, a second coil (receiver coil) can be arranged on each of both end faces of the first coil (transmitter coil). In this case, one first coil (transmitter coil) requires two coils. A coin-shaped object in the passage can be detected.
Effective use of two first coils (transmitting coils) and simplification of the configuration are obtained.

Further, when the sensor is configured as a game medal detection sensor, it is possible to detect a medal at a slot of a game machine (for example, a slot machine) and to use a game medal counting machine to detect a valid medal. it can.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The drawing shows a slot machine (pachislot) installed in a game hall. In FIG. 1, the slot machine 11 has a medal M
Is opened one by one to receive the sheets one by one.
The inside of the regular-sized medal that was thrown into 2,
A sorting function for returning medals of an inappropriate size to the external return port 13 is provided. Also, a return button 14 is provided next to the slot 12, and the medal M is returned to the return port 13 even when the player presses the return button 14 to stop the game.

FIG. 2 shows an inner surface state of the slot machine 11 in which the front door 15 is opened in a one-sided manner. The opened slot machine body 11a has a reel 16 at an upper part and a medal take-in at a lower part. Hopper 17, a medal return passage (not shown), and a power supply device 18.

On the other hand, a reel cover 19, an inserted medal selection device (medal selector) 20, and a return slot 13 are arranged in this order on the inner surface of the front door 15 side.

FIGS. 3 and 4 show the inserted medal selecting device 20.
In the inserted medal selection device 20, a U-shaped substrate 21 and an opening / closing plate 22 are integrally combined to form a medal passage 23 for inserted medal selection, and the outside thereof is covered with a U-shaped cover 24 and integrally formed. I have.

The above-described medal passage 23 is provided in the upper slot 1
A vertical path 23a between the inlet 25 and the lower outlet 26, which correspond to the connection 2 and a sloping path 23b which is gently inclined from the vertical path 23a.
And are connected to each other.

A movable protrusion 27 for stably lowering the medals, which protrudes horizontally from the back side toward the passage side, is provided on the U-shaped substrate 21 side of the vertical path 23a.
Is lightly urged from behind by a light load spring (not shown) to hold it in a protruding state.

Therefore, even if medals are continuously inserted, the movable protruding piece 27 guides and accepts the medals guided here one by one. The take-in operation can be performed, and the light can be decelerated by lightly touching the medal M that descends vigorously.

The above-mentioned ramp 23b of the medal passage 23 is
It is provided at an angle of about 15 ° with respect to the thickness direction of the standing medals.

The inclination angle is set so that the opening / closing plate 22 is inclined downward, and the medals M rolled and conveyed in the inclined path 23b are conveyed while being inclined toward the opening / closing plate 22 on the inclined lower side. . As a result, when an inappropriate medal with a small diameter is inserted, the medal starts to incline downward in the thickness direction of the medal due to its own weight, and falls down to the discharge port 28 of the opening / closing plate 22 facing the lower incline. And is guided to the return port 13 described above.

A medal detection sensor unit 30 is disposed on the above-described ramp 23b of the medal passage 23, immediately before the exit 26 thereof.

The above-mentioned medal detection sensor unit 30
As shown in FIG. 5, a transmission coil 31 for transmission, which is a magnetic flux generation source, and two reception coils 32a, 32b for reception, which generate inductive output under the influence of magnetic flux, are provided inside the medal passage 23. The two receiving coils 32a and 32b are arranged at predetermined intervals along the rolling direction of the medal M and housed in a housing 33 made of synthetic resin.

FIG. 6 is a circuit block diagram of a medal detection sensor constituted by using the above-mentioned transmission coil 31 and reception coils 32a and 32b. The transmission coil 31 is constituted by one transmission processing circuit, but the reception coil is constituted by one transmission processing circuit. Coils 32a, 32
b represents a reception processing circuit.

As will be described in detail later, the transmitting circuit 34 intermittently drives the transmitting coil 31 with a pulse signal having a predetermined time width, and the receiving circuits 35a and 35b respectively receive the receiving coils 35a and 35a under the influence of the magnetic flux of the transmitting coil 31. The inductive output generated at 35b is taken out, each of the integrating circuits 36a and 36b detects and integrates the inductive output of the preceding stage, and each of the comparing circuits 37a and 37b uses a voltage level set in advance to determine the presence or absence of the medal M. Is compared with the integrated voltage value of the preceding stage, and as a result of the comparison, when it is determined that the medal M exists, each output circuit 38
a, 38b to output a medal detection signal.

It should be noted that the above-described comparison is determined by the transmission coil 31.
Since the intermittent transmission is performed on the side, execution is performed in response to the output of the intermittent cycle. In addition, the detection of the passage of one medal M is performed based on the result of one or more intermittent period determination processes.

FIG. 7 shows the output state of the reception processing circuit side. Since the two reception coils 32a and 32b are arranged at a predetermined interval in the rolling direction of the medal M, the respective medal detection signals ( There is a time difference between output 1 and output 2).

Therefore, by determining the output order, the rolling direction of the medal M can be determined. It is possible to detect the fraudulent activity.

FIG. 8 shows the transmission circuit 34 described above. The transmission circuit 34 includes a DC power supply 41 for applying a power supply voltage to the transmission coil 31 and a constant current source (constant current power supply) for supplying a constant current.
And a switching transistor 43 intermittently driving the supply of the DC power supply 41 and the constant current source.
And an intermittent wave generator 44 for generating an intermittent wave (pulse signal) with a predetermined width and a predetermined cycle in order to drive the transistor 43 intermittently. In the figure, R is a resistor, C
Is a capacitor.

The transmission circuit 34 configured as described above switches the transistor 43 at a predetermined cycle by an intermittent wave signal generated by the intermittent wave generator 44, that is, a pulse signal (electrically connected / disconnected drive). Then, the transmission coil 31 intermittently oscillates to generate an intermittent magnetic flux.

The following operation occurs by the switching operation of the switching transistor 43 described above.

That is, as shown in FIG. 9, when the transmission coil 31 is driven by one pulse signal (intermittent wave signal) and excited to oscillate, the reception coils 32a and 32b are affected by the magnetic flux excited by the pulse signal. At the transition points T1, T2, T3, and T4 of the rise and fall of the excited magnetic flux, and a large induction output is generated at the transition point (large output). Occurrence of amplitude with peak value).

That is, as a first feature, by the intermittent driving of the transmission coil 31, an induction output having a large peak value is obtained on the side of the reception coils 32a and 32b corresponding to the rising and falling points of the magnetic flux. Can be

Further, the pulse change point T in FIG.
3. At T4, when the induction output generated at the change point T4 is superimposed on the output remaining portion of the induction output generated at the change point T3, it is possible to obtain a larger induction output (an amplitude having a large peak value). Occurrence).

That is, as shown in FIG. 10, an inductive output is generated in the plus (+) direction at the transition point which rises when the pulse is turned ON (FIGS. 10, a, b). Also, the pulse O
At the transition point that has fallen at the FF, an induced output is generated in the minus (-) direction (FIGS. 10, c and d), and the pulse is utilized by utilizing the fact that it has a phase (cycle) shift of 180 degrees. The pulse is dropped at the timing when the waveform of the induced output generated by the rising edge changes in the minus (-) direction, and the induced output generated by the falling edge is superimposed on the induced output generated by the rising edge, so that a larger value is obtained. An induced output having an amplitude having a peak value is obtained (FIGS. 10, e, f).

Of course, the above-mentioned pulse signal width is 0.5 times, 1.5 times, and 2.5 times the oscillation period determined by the characteristics of the receiving coils 32a and 32b and the resonance capacitance, and is, as shown in FIG. It may be set to a time obtained by adding a half cycle to an integer multiple (integer multiple + half cycle), and without shifting the half cycle exactly,
The width may be set so as to overlap in a direction in which the amplitude increases.

That is, as a second feature, the pulse signal width for intermittently driving the transmission coil 31
By setting the signal width to be superimposed and synthesized in a direction in which the amplitude of the oscillation period on the side of a, 32b increases, an induced output having an amplitude having a larger peak value can be obtained.

FIG. 11 shows the output waveforms of the transmitting coil 31 and the receiving coils 32a and 32b described with reference to FIG. 8, and the width of the pulse signal (intermittent signal wave) of the intermittent wave generator 44 is as described above. The phase (period) of the oscillation waveform on the receiving side
Is set to a width (time width) at which a shift of 180 degrees (half cycle) occurs, and oscillates at a predetermined cycle (FIG. 11, a). When the excitation oscillation occurs, the oscillation signal waveform becomes
It oscillates at an amplitude with an extremely high peak value, far exceeding the power supply voltage Vcc (FIG. 11, b).

The receiving coils 32a and 32b which receive such excited and oscillated magnetic flux become superposed composite waves, so that an induced output waveform having an extremely high peak value can be obtained (FIG. 11, c). This means that the excitation oscillation of the transmission side is received with high sensitivity, and as a result, the reception sensitivity can be expanded from the minimum required sensitivity to the maximum sensitivity, and the margin of the reception range is improved. Thus, the reception range can be expanded, and the distance between the transmission coil 31 and the reception coils 32a and 32b can be increased.

Further, when the set current value of the constant current source 42 is increased, the peak value of the induction output of the receiving coils 32a and 32b can be increased regardless of the power supply voltage value of the DC power supply 41. The receiving sensitivities of 32a and 32b can be increased, which also improves the margin of the receiving range and can extend the detection distance.

As a result, the distance between the transmitting coil 31 and the receiving coils 32a and 32b can be set to a necessary and sufficient distance, so that the width of the medal path 23 (in the thickness direction of the medal M) is set to a necessary and sufficient width. Even if it is set, the medal M can be reliably detected.

In the above embodiment, the transmission circuit 34
Although the constant current source 42 is interposed in the circuit, the medal M can be sufficiently detected by the intermittent drive by the intermittent wave generator 34 even if the constant current source 42 is omitted.

Further, in the above-described embodiment, the circuit configuration of the transmission processing circuit of the transmission coil 31 and the reception processing circuit of the reception coils 32a and 32b may be configured in the medal detection sensor unit 30 or in the slot machine 11. It may be configured on a control board.

Furthermore, two medical examination coils 32a and 32b are arranged to detect the rolling direction of the medal M, but when it is not necessary to detect the rolling direction of the medal M,
One of the receiving coils 32a or 32b and its receiving processing circuit can be used. FIG. 12 shows another embodiment. This embodiment is, for example, a counting device for counting medals M, in which two medal paths A and B are juxtaposed for rolling the medals M. For example, one transmission coil 31 for transmission is arranged at an intermediate point between the medal paths A and B, and the reception coils 32a and 32b are sandwiched between both ends of the transmission coil 31 with the medal paths A and B interposed therebetween. They are arranged facing each other. The functions of the transmission processing circuit and the reception processing circuit are the same as those of the configuration shown in FIG.

With this configuration, one transmission coil 31 and a transmission processing circuit are connected to two reception coils 32a,
32b and these reception processing circuits can be used, and the circuit configuration is simplified.

FIG. 13 shows still another embodiment. In this embodiment, coins of a plurality of denominations, for example, 500-yen coins, 100-yen coins, and 1-yen coins are arranged inside a coin slot of a vending machine.
An example of a coin detection sensor applied to discriminate a denomination such as a zero yen coin will be described.

The transmission coil 31 and the reception coil 32 are arranged opposite to each other with the coin path C interposed therebetween. The functions of the transmission processing circuit connected to the transmission coil 31 and the reception processing circuit connected to the reception coil 32 are as follows. Since the circuit configuration is the same as that shown in FIG. 6, the same reference numerals are given and the description of the functions is omitted, but the detection integration output from the integration circuit 36 is output to three types of comparison circuits 37a, 37b and 37c. You.

These comparison circuits 37a, 37b, 37c
Are set in accordance with the coins of the denomination to be identified. For example, the receiving state of the receiving coil 32 (the state of interrupting the magnetic flux) depends on the material of the coin, its diameter, and the form of the thickness.
Therefore, the respective comparison reference values are set so that the difference can be discriminated. For example, when the denomination A has a high magnetic flux cutoff rate, the denomination B has a medium flux cutoff rate, and the denomination C has a low cutoff rate, the first comparison circuit 37a discriminates the denomination A. A corresponding comparison reference value is set, a second comparison circuit 37b is set with a comparison reference value corresponding to discriminating B denomination, and a third comparison circuit 37c is set corresponding to discrimination of C denomination. Set the comparison reference value.

When the determination signal is output from all of the first, second, and third comparison circuits 37a, 37b, and 37c with the above setting, the denomination of the A type is determined, and the second and third denominations are determined. When the discrimination signal is output from the comparison circuits 37b and 37c, the denomination B can be determined, and when only the third comparison circuit 37c is output, the denomination C can be determined.

In this manner, the denomination of the coin can be determined.

In the correspondence between the configuration of the present invention and the above-described embodiment, the coin-shaped body of the present invention corresponds to the medal M and the coin of the embodiment. The transmission coil 31 and the reception coil 32 of the detection sensor unit 30 and the transmission processing circuit and the reception processing circuit connected thereto, further correspond to the coin detection sensor, the first coil corresponds to the transmission coil 31, Are the receiving coils 32 (32a, 32a).
Corresponding to b), the intermittent driving means corresponds to the intermittent wave generator 44 and the switching transistor 43. However, the present invention is not limited to the configuration of the embodiment, but includes many embodiments.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a slot machine.

FIG. 2 is a front view showing the inside of the slot machine with a front door opened.

FIG. 3 is a perspective view of a main part of the inserted medal selection device.

FIG. 4 is an exploded perspective view of the inserted medal selection device.

FIG. 5 is a perspective view of a medal detection sensor unit.

FIG. 6 is a circuit block diagram of a medal detection sensor.

FIG. 7 is a time chart of a detection signal.

FIG. 8 is a circuit block diagram of a transmission side.

FIG. 9 is an explanatory diagram of an oscillation waveform.

FIG. 10 is an explanatory diagram showing a relationship between a pulse and an oscillation waveform.

FIG. 11 is an explanatory diagram of output waveforms of a transmission circuit unit and a reception circuit unit.

FIG. 12 is a main part circuit block diagram of a medal detection sensor showing another example.

FIG. 13 is a circuit block diagram of a coin detection sensor showing another example.

[Explanation of symbols]

 30 ... Medal detection sensor unit 31 ... Transmission coil 32,32a, 32b ... Reception coil M ... Medal 34 ... Transmission circuit 35,35a, 35b ... Reception circuit 36,36a, 36b ... Integration circuit 37a, 37b, 37c ... Comparison circuit 38a 38b, 38c output circuit 42 constant current source 43 switching transistor 44 intermittent wave generator

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3E002 AA13 AA18 BC06 CA04 CA09 DA06 DA10 EA03 EA05 EA10

Claims (7)

[Claims] 1. A coin-shaped body detection sensor for detecting a metal coin-shaped body moving in a passage, comprising: a first coil serving as a magnetic flux generating source; and a second coil generating an induction output under the influence of the magnetic flux. And the coil is disposed to face each other with the path interposed therebetween, and an intermittent drive unit for intermittently driving the drive is provided to intermittently excite the first coil, thereby moving the coin-shaped body in the path between the two coils. A coin-shaped body detection sensor that detects the magnitude of the induction output of the second coil. 2. The apparatus according to claim 1, wherein a plurality of said second coils are arranged facing said first coil along a moving direction of said coin-shaped body.
The coin-shaped body detection sensor according to 1. 3. A plurality of receiving circuits, each having a different discrimination reference value set, are connected to the second coil, and the type of coin is determined by a combination of signals detected and not detected by these receiving circuits. The coin-shaped object detection sensor according to claim 1, wherein the detection is performed. 4. A coin-shaped object detection sensor according to claim 1, wherein a constant current source is used as an electric energy supply source for intermittently driving said first coil. 5. An intermittent driving means for intermittently exciting the first coil to set an intermittent signal width to a period of an induced oscillation wave of a second coil generated at a rise of the intermittent signal and a fall of the intermittent signal. 4. The coin-shaped object detection sensor according to claim 1, wherein the width of the induced oscillation wave of the second coil generated in the step (c) is set to a width that is superimposed and synthesized in a direction of increasing amplitude. 6. The coin-shaped object detection sensor according to claim 1, wherein the signal width of the intermittent signal is set to an integral multiple of an oscillation cycle determined by a resonance frequency of the second coil + a half cycle time. . 7. A game medal detection sensor according to claim 1, wherein said coin-shaped body detection sensor comprises means for detecting a game medal.