Coin discriminator

• US 5,833,042 A
• Filed: 06/17/1996
• Issued: 11/10/1998
• Est. Priority Date: 12/17/1993
• Status: Expired due to Term

• Current Assignee: Microsystem Controls Pty., Ltd.
• Original Assignee: Microsystem Controls Pty., Ltd.
• Inventors: Baitch, Alexander, Phillips, Lawrence Peter, Wolstoncroft, Phillip Andrew, Korecki, Nikola, Malzard, Norman Raymond
• Primary Examiner(s): Bartuska, F. J.
• Application Number:
  US08/652,471
• Time in Patent Office: 876 Days
• Field of Search: 194/317, 194/318, 194/319
• US Class Current: 194/317
• CPC Class Codes: G07D 5/00 Testing specially adapted to determine the identity or genuineness of coins, e.g. for segregating coins which are unacceptable or alien to a currency
• CPC Class Codes: G07D 5/08 Testing the magnetic or electric properties

Abstract

A method of categorizing coins/tokens by energizing detect coils with a single pulse detecting the back EMF curve of the decaying pulse information, analyzing the unmodified back EMF curve to extract therefrom a number of variables and processing those variables to provide values proportional to the variables, and comparing the values of the coin/token to at least one of a number of reference values to determine into which of a number of predetermined categories the coin/token falls.

Claims

1. A method of categorizing coins/tokens, including the steps of:

(a) energizing detect coils, between which at least part of a coin/token is located, with a single pulse,

(b) detecting the unmodified back EMF curve of the decaying pulse,

(c) analyzing said unmodified back EMF curve to measure at least one characteristic of said unmodified back EMF curve,

(d) comparing said at least one characteristic with the corresponding characteristic(s) of a reference unmodified back EMF curve to determine therefrom into which of a number of predetermined categories said coin/token falls.

2. A method as claimed in claim 1, wherein said at least one characteristic of said unmodified back EMF curve includes any one or more of;

the amplitude of the oscillating wave form, the amplitude of the direct current component, the phase angle of the response triggering delay, the frequency of oscillation, the decay associated with the oscillating waveform, and the decay associated with the direct current component.

3. A method as claimed in claim 2, wherein the amplitude of the oscillating wave form, the amplitude of the direct current component, the decay associated with the oscillating waveform, and the decay associated with the direct current component are the characteristics used as the basis of said comparison.

4. A method as claimed in claim 1, wherein said at least one characteristic of said unmodified back EMF curve comprises a superimposition of a mean amplitude curve.

5. A method as claimed in claim 1, wherein said at least one characteristic of said unmodified back EMF curve comprises the phase and/or change in phase of the oscillating waveform.

6. A method as claimed in claim 1, wherein said at least one characteristic of said unmodified back EMF curve comprises the curves plotted by the peaks of either or both of the positive and/or negative portions of the oscillating waveform, and the amplitude of the negative and/or positive peaks of the oscillating waveform.

7. A method as claimed in claim 1, wherein said at least one characteristic of said unmodified back EMF curve comprises the area of the curve beneath the peaks of the oscillating waveform.

8. A method as claimed in claim 1, wherein said at least one characteristic of said unmodified back EMF curve comprises the frequency and/or change in frequency of the oscillating waveform.

9. A method as claimed in claim 1, wherein said at least one characteristic of said unmodified back EMF curve comprises the decay of the peaks of the oscillating waveform in a predetermined time.

10. A method as claimed in claim 1, wherein said at least one characteristic of said unmodified back EMF curve comprises a combination of at least two characteristics selected from the group consisting of:

(a) representation of a superimposition of a mean amplitude curve;

(b) representation of the phase of the oscillating waveform;

(c) representation of the change in phase of the oscillating waveform;

(d) representation of the curve plotted by the peaks of the positive portions of the oscillating waveform, and the amplitude of those peaks;

(e) representation of the curve plotted by the peaks of the positive portions of the oscillating waveform, and the amplitude of the peaks of the negative portions of the oscillating waveform;

(f) representation of the curve plotted by the peaks of the negative portions of the oscillating waveform, and the amplitude of those peaks;

(g) representation of the curve plotted by the peaks of the negative portions of the oscillating waveform, and the amplitude of the peaks of the positive portions of the oscillating waveform;

(h) representation of the curves plotted by the peaks of both the positive and the negative portions of the oscillating waveform, and the amplitude of those peaks;

(I) representation of the areas of the curves beneath the peaks of the oscillating waveform;

(j) representation of the frequency of the oscillating waveform;

(k) representation of the change in frequency of the oscillating waveform;

(l) representation of the frequency and the change in frequency of the oscillating waveform; and

(m) representation of the decay of the peaks of the oscillating waveform in a predetermined time.

11. A method of catagorising coins/tokens, including the steps of:

(a) energising detect coils, between which at least a part of a coin/token is located, with a single pulse,

(b) detecting the back EMF curve of the decaying pulse information,

(c) analysing the unmodified back EMF curve to extract therefrom a number of variables and processing those variables to provide values proportional to the variables,

(d) comparing said values of said coin/token with a number of reference values to determine into which of a number of pre-determined categories said coin token falls;

said comparison being made using the formula

space="preserve" listing-type="equation">V(t)=Ae.sup.-σ

t sin (ω

t+φ

)+Be.sup.-α

t

wherein;

V(t) is the voltage at time t

A is the amplitude of the oscillating waveform

B is the amplitude of the direct current component

φ

is the phase angle of the response triggering delay

ω

is 2π

ƒ

ƒ

is the frequency of oscillation

σ

is the decay associated with the oscillating waveform

α

is the decay associated with the direct current component.

12. A method as claimed in claim 11, wherein an indication of the combined effects of A and B is obtained by integration of the back EMF curve for an odd number of half-cycles.

13. A method as claimed in claim 11, wherein an indication of the combined effects of σ

and α

is obtained by integration of an even number of half-cycles.

14. A method as claimed in claim 11, wherein an indication of the frequency is obtained by the measurement of the period for a number of cycles.

15. A method of categorizing coins/tokens, including the steps of:

(a) energizing detect coils, between which at least part of a coin/token is located, with a single pulse;

(b) detecting the back EMF curve of the decaying pulse information;

(c) analyzing the unmodified back EMF curve to extract therefrom one or more variables and processing said one or more variables to provide values proportional to said one or more variables; and

(d) comparing said values of said coin/token with at least one of a number of reference values to determine into which of a number of predetermined categories said coin/token falls, wherein said comparison is made using the formula

space="preserve" listing-type="equation">V(t)=Ae.sup.-σ

t sin (ω

t+φ

)+Be.sup.-α

t

wherein;

V(t) is the voltage at time t

A is the amplitude of the oscillating wave form

B is the amplitude of the direct current component

φ

is the phase angle of the response triggering delay

ω

is 2π

ƒ

ƒ

is the frequency of oscillation

σ

is the decay associated with the oscillating waveform

α

is the decay associated with the direct current component.

16. A method of categorizing coins/tokens, including the steps of:

(a) energizing detect coils, between which at least part of a coin/token is located, with a single pulse;

(b) detecting the back EMF curve of the decaying pulse information;

(c) analyzing the unmodified back EMF curve to extract therefrom one or more variables and processing said one or more variables to provide values proportional to said one or more variables; and

(d) comparing said values of said coin/token with at least one of a number of reference values to determine into which of a number of predetermined categories said coin/token falls, wherein the step of analyzing the unmodified back EMF curve comprises the steps of;

comparing said unmodified back EMF curve to a reference unmodified back EMF curve; and

determining said values by calculating the difference of said one or more variables between said unmodified back EMF curve and said reference unmodified back EMF curve.