JPS6265187A - Coin detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a coin detection device for detecting the presence or absence of coins in a change cylinder of a coin processing device of a vending machine (hereinafter referred to as fin mechanism).

Conventional technology Conventionally, in an LC resonant circuit composed of a detection coil and a capacitor, the impedance of the detection coil changes depending on the presence or absence of a coin near the detection coil, and by monitoring the convergence of ringing. It has been used to determine the presence or absence of coins.

For example, FIG. 3 shows a conventional coin detection device in a change cylinder. In FIG. 3, 1A is a change cylinder in which a detection coil in the coin mechanism is installed, Llo is a detection coil installed in the change cylinder 1A, C10 is a capacitor that forms an LC resonance circuit with the detection coil L10,
R20 is a current limiting resistor, Q10 is a transistor that drives the LC resonant circuit, R24 is a base resistor, and IC3
A is a comparator that shapes the ringing convergence waveform into a square wave, R25 and R26 are resistors that set the threshold level of comparator IC3A (7), and R21 is comparator IC3.
A resistor that sets the hysteresis width of A, R22 is the comparator I
C3A pull-up resistor, IC1A is transistor Q1
Output port P0 and comparator I C3A to control
A CPU that is equipped with a counter input board that counts the number of pulses from the
(microcomputer).

FIG. 4 is a time chart for the configuration of FIG. 3.

Figure 6 is a diagram showing a method for determining the presence or absence of coins based on the pulse count number at the counter input of the CPU/IC1A in Figure 3.When the count number is less than or equal to the set value 01, there is a coin present, and when it is greater than or equal to the set value 02, there is a coin. When the value is between none and C and 02, a determination is made to maintain the previous state. Note that the values of C1 and C2 are normally set to C1<C2. FIG. 6 is a sectional view of the change cylinder 1A in which the detection coil L1o of FIG. 3 is installed. In Figure 6, A is a coin.

The operation of the coin detection device configured as described above will be explained below. First, in the standby state, the CPU-I
The output port P0 of C1A is at "H" level, the transistor Q1o is in a conductive state, and a current flows through the detection coil LjO. Therefore, the input of comparison 5ICaA is fixed to Ov. Next, in order to detect the presence or absence of a coin, the output port P0 of the CPU-IC1A falls from the "H" level to the "L" level, and the transistor Q10
becomes blocked. Then, at the same time as transistor Q1o is cut off, a back electromotive force is generated in sensing coil L10, current flows from sensing coil L1o to capacitor C1o, and capacitor C1° is charged. Then, when this charging is completed, the capacitor C10 is then discharged to the detection coil L10. In this way, charging and discharging are repeated one after another, and the amplitude of the ringing pulse converges as shown in FIG. 4 due to the equivalent resistance r of the parallel resonant circuit. Note that this equivalent resistance r increases due to the thin current when there is a coin near the detection coil 9, and the amplitude of the ringing pulse converges earlier than when there is no hard object.

When this ringing pulse crosses a certain threshold level of comparator IC3A, comparator IC3A
The waveform is shaped into a square wave by Cp.
tJ-IC1A is counted, and this counted number "C" is compared with the values C and C2 preset in the CPU/IC1A as described above, and the presence or absence of coins is determined as follows.

When C≦01, there is a coin present. When C1<C<02, there is no change in the state. When C≧02, there is no coin. The above is the operation when there is only one change cylinder, but in reality When used with a fin mechanism, the mainstream is to use four denominations: 10 yen, 50 yen, 100 yen, and SOO yen, and to have four or more change tubes. Furthermore, if each cylinder is to detect change and detect fullness, eight detection coils are required.

FIG. 7 shows the configuration of a coin detection device using eight detection coils when actually used in a coin mechanism. In FIG. 7, 1B is a change tube in which a detection coil is installed, L21 to L28 are detection coils installed in the change tube 1B, 021 to 028 are capacitors that constitute an LC resonance circuit with detection coils L21 to L2B, and R31 ~R38
is a current limiting resistor, IC3B is a comparator that shapes the ringing convergence waveform into a square wave, R39 and R40 are resistors that set the threshold level of comparator IC3B, and R41 sets the hysteresis width of comparator IC3B. R43 to R50 are the input resistances from the respective LC resonant circuits to the comparator IC3B, R51 to R58 are the base resistances of the transistors Q11 to Q18, R42 is the pull-up resistor of the comparator IC3B, and R59 to R86 are the BCD decoders. IC2A output stage pull-up resistor, R67~R
Reference numeral 69 indicates a pull-up resistor for the output ports P0 to P2 of the CPU IC1B, and IC1B is an output port P for providing an LC resonant circuit selection signal to the BCD decoder IC2. -R2
The above-mentioned CPU, IC2A, is equipped with a counter input port that counts the number of pulses from the comparator IC3B, and determines the presence or absence of coins based on this counted number.
The above-mentioned BCD decoder, Q11~, converts the selection signal of the LC resonant circuit based on the BCD code from B into a decimal number.
Q18 is the detection coil L21 to L28 and capacitor 021
This is the above-mentioned transistor that drives the LC resonant circuit composed of . FIG. 8 is a time chart in FIG. 7.

The operation of the coin detection device configured as described above will be explained below. First, when determining the presence or absence of a coin using the detection coil L21, the transistor Q11 is conductive in the standby state, and current flows through the detection coil L21. Next, the operation when detecting the detection coil L21 is as shown in FIG.
By setting all the signals of 2 to "L" level, the decoder I
The output 0 of C2A falls from the "H" level to the "L" level. When the output O of the decoder IC2A becomes "L" level, the transistor Q11 is cut off, and a ringing pulse is generated in the detection coil L21 and the capacitor C21. Then, the presence or absence of a coin is determined by using this ringing pulse inputted to the comparator IC3B through the input resistor R43 in a manner similar to that already described in FIG.

Similarly, when determining the presence or absence of a coin using the detection coil L22, the output port P0 of the CPU-ICIB is set to H#,
Output port p1. Set p2 to "L" level. Similarly, output port P0. By changing the level of P1°R2, an arbitrary detection coil is selected, and the presence or absence of a coin is detected from that detection coil.

Problems to be Solved by the Invention In such a conventional circuit, the same number of transistors as the number of LC resonant circuits are required to apply a pulse to each LC resonant circuit. Moreover, since all other transistors are conductive while detecting the presence or absence of coins, the input stage of the comparator is pulled down through a resistor, and as the number of LC resonant circuits increases, the input stage of the comparator There was a practical problem in that the amplitude of the ringing pulse was reduced due to voltage division, making it susceptible to external noise and power supply noise. Furthermore, since the input level to the comparator is small, the resistors that determine the threshold level and hysteresis width are required to be highly accurate and expensive. It is an object of the present invention to provide a coin detection device that has a simple configuration, can obtain a large input level regardless of the number of detection coils, is inexpensive, and is less susceptible to external noise.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides the same number of analog switches as the number of detection coils next to the transistor for applying pulses to the detection coils, and switches these analog switches. This allows the determination of the presence or absence of coins to be arbitrarily selected using individual detection fills.

Operation The present invention uses the above-described configuration to provide pulses to the detection coil. Only one transistor is required, and the input level of the comparator is not affected by the number of detection coils.
The difference in the impedance change of the detection coil depending on the presence or absence of a coin can be obtained with high accuracy.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a coin detection device in an embodiment of the present invention. In Fig. 1, 1 is a change tube in which a detection coil is installed, L1 to L8 are detection coils installed in the change tube, and 01 to C8 are detection coils L1 to L8.
A capacitor that constitutes a resonant circuit, R1 is each detection coil L
A current limiting resistor common to 1 to L8, IC3 a comparator that shapes the ringing convergence waveform into a square wave, R9, R1
゜ is a resistor that sets the threshold level of comparator IC3, R11 is a resistor that sets the hysteresis width of comparator IC3, R12 is a pull-up resistor of comparator IC3, R
13 is the pull-up resistor of the input stage of comparison 5IC3, R14
~R17 is the pull-up resistor of the output ports P0 to P3 of the CPU/IC1, R18 is the base resistor of the transistor Q1, and IC1 is the analog switch IC2 and the detection coil L1~
The above-mentioned CP is equipped with output ports P0 to P3 for providing the selection signal of L8 and the drive signal of transistor Q1, and a counter input port for counting the number of pulses from the comparator IC3, and determines the presence or absence of coins based on the counted number.
U and IC2 are the above-mentioned analog switches with a BCD decoder that converts the detection coil selection signal from the CPU IC1 into a decimal number and switches each LC resonant circuit with the signal, and Ql is a transistor that drives the parallel resonant circuit. be. Further, the reason why the voltage applied to the detection coils L1 to L8 is set to 2.6V is due to the input protection diode of the analog switch IC2 and the limitation of the input range of the comparator IC3.

FIG. 2 is a time chart for the configuration of FIG. 1.

The operation of the coin detection device configured as described above will be explained below. First, in the case of the detection coil L1, the transistor Q1 is cut off in the standby state, and no current flows through any of the detection coils. Therefore, the input of comparator IC3 is fixed at 2.5V. next,
The operation when determining the presence or absence of a coin by the detection coil L1 is as follows.
As shown in Figure 2, the output ports P0 to P2 of the CPU C1
is set to the L" level to select the detection coil L1, and at the same time, the output port P3 is set to the "H" level to make the transistor Q1 conductive, thereby causing a current to flow through the detection coil L1. Next, after a certain period of time T1, the output port P3 of the CPU/IC1 is set to "L" level to turn off the transistor Q1. Here, T1 only needs to be longer than the time required for the current flowing through the detection coil to reach a steady state, and is actually 0.
, 5 m5IK is set. Then, when the transistor Q1 is cut off, the detection coil L1 and the capacitor C
1, a ringing pulse is generated. The ringing pulse thus inputted to the comparator IC3 through the analog switch IC2 is used to determine the presence or absence of a coin near the detection coil L1 in the same manner as described in FIG. 3 above. Similarly, when determining the presence or absence of a coin using the detection coil L2, set the output port P0 of the CPU-IC1 to "H", P
1 is set to "L" level, R2 is set to "L" level, and R3 is set to "H" level, and after a certain period of time T1, output port P3 is set to "L" level to detect the presence or absence of coins.

Thereafter, in the same manner, output port P0. P1. P2゜R3
By changing the level of , an arbitrary detection coil is selected and the presence or absence of a coin is detected by the detection coil.

In the explanation of this embodiment, a method was explained in which the number of ringing pulses is counted and the presence or absence of a coin near the detection coil is determined based on the magnitude of this number of pulses. Possible methods include determining the presence or absence of a coin near the detection coil based on the magnitude of the ringing voltage or current, or measuring the integral value of the ringing voltage or current and determining the presence or absence of a coin near the detection coil based on the magnitude of the , these methods can also provide the same effects as the method of this embodiment.

Furthermore, in the above embodiment, an LC resonant circuit configured by connecting detection coils L1 to L8 and capacitors 01 to C8 in parallel was shown, but this can also be applied to an LC resonant circuit configured by connecting them in series. be.

Effects of the Invention As described above, according to the present invention, a large input to the comparator can be obtained with a simple circuit configuration and at low cost regardless of the number of detection coils, thereby reducing the influence of external noise and power supply noise. This makes it possible to detect the presence or absence of coins in the vicinity of the detection coil with high precision, making it extremely useful in practice.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a circuit diagram showing the configuration of a coin detection device in an embodiment of the present invention, FIG. 2 is a diagram illustrating a time chart of the coin detection device in an embodiment of the present invention, Fig. 3 is a block diagram of a conventional coin detection device using one detection coil, Fig. 4 is a diagram explaining a time chart of the coin detection device of Fig. 3, and Fig. 6 is a coin detection device of Fig. 3. Judgment diagram showing the method for determining the presence or absence of coins based on the pulse count number of the device, No. 6
The figure is a cross-sectional view of the change tube in which the detection coils are installed in the device shown in FIG. 3, FIG. 7 is a block diagram of a conventional coin detection device using eight detection coils, and FIG. It is a figure explaining the time chart of the coin detection device using eight detection coils. IC1...Microcomputer (CPU),
IC2...Analog switch, IC3...
・Comparator, Ql...transistor, L1 to L8
...Detection coil, C1-Cs...Capacitor. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 5
Figure 6

Claims (4)

[Claims] (1) A plurality of LC resonant circuits in which a detection coil and a capacitor are connected in parallel or in series, an analog switch connected to these LC resonant circuits and sequentially selecting each LC resonant circuit one by one, and a
and a determination control circuit that intermittently supplies current to a resonant circuit and determines the presence or absence of a coin near a plurality of the detection coils based on the convergence state of ringing that occurs in the LC resonant circuit when the current is interrupted. Detection device. (2) The judgment control circuit counts the number of ringing pulses that occur in the LC resonant circuit, and depending on the magnitude of this number of pulses,
The coin detection device according to claim 1, which is configured to determine the presence or absence of a coin near the detection coil. (3) The coin detection according to claim 1, wherein the determination control circuit measures the convergence time of ringing occurring in the LC resonance circuit, and determines the presence or absence of a coin near the detection coil based on the magnitude of this time. Device. (4) The determination control circuit is configured to measure the integral value of the voltage or current of ringing occurring in the LC resonance circuit, and determine the presence or absence of a coin near the detection coil based on the magnitude of the integral value. Coin detection device described.