Electronic coin acceptor

A coin inspecting circuit for testing the acceptability of coins of at least two different denominations, comprising:

• means for generating an input driving signal having a selectively variable characteristic;
• means for controlling said selectively variable characteristic of said driving signal such that at least one predetermined testing characteristic for each coin denomination to be tested for acceptability is selected for said driving signal in a predetermined sequence;
• means for creating an electromagnetic field which is varied in response to said driving signal and for producing a sequence of alternating signals which are responsive to a conductive object in the presence of said electromagnetic field;
• means for detecting when each said alternating signal crosses a predetermined threshold level and for producing a level detect signal indicative of each said threshold crossing;
• and
• means for determining whether a conductive object in the presence of said magnetic field is an acceptable coin from said level detect signal.

In an apparatus which is operable in response to the receipt of at least one acceptable coin, an electronic coin acceptor for testing the acceptability of received coins comprising:

• frequency synthesizer means for generating a driving signal having a selectively variable frequency;
• inductive filter means for creating an electromagnetic field and for producing an alternating signal which is responsive to a conductive object in the presence of said electromagnetic field;
• comparator means for detecting when said alternating signal crosses a predetermined threshold level and for producing a level detect signal indicative of said threshold crossing;
• and
• microcomputer means for controlling said frequency synthesizer means by selecting predetermined frequencies for said driving signal, for sensing the entrance of a conductive object into said electromagnetic field, and for determining whether a conductive object in the presence of said electromagnetic field is an acceptable coin.

A method of testing the acceptability of a coin, comprising the steps of:

• providing at least one input setting characteristic for each coin denomination to be tested for acceptability;
• creating an electromagnetic field which is varied in response to said testing characteristics in a predetermined sequence;
• and
• measuring the effect upon said electromagnetic field when a conductive object is in the presence of said electromagnetic field;
• and
• determining whether a conductive object in the presence of said electromagnetic field is an acceptable coin from the changes in said electromagnetic field.

A method of testing the acceptability of a coin in a coin operated apparatus, comprising the steps of:

• generating an input driving signal with a predetermined sequence of testing frequencies, at least one testing frequency being provided for each coin denomination to be tested for acceptability;
• creating an electromagnetic field in response to said driving signal and producing a sequence of alternating signals which are responsive to a conductive object in the presence of said electromagnetic field;
• detecting when each said alternating signal crosses a predetermined threshold level and producing a level detect signal indicative of each said threshold crossing;
• and
• determining whether a conductive object in the presence of said magnetic field is an acceptable coin from said level detect signal.

A method of dynamically testing the acceptability of coins in a coin operated apparatus, comprising the steps of:

• establishing a criteria for determining the acceptability of at least one coin denomination;
• testing a conductive object to determine whether said conductive object is an acceptable coin;
• producing at least one resulting signal from said test;
• determining whether said conductive object is an acceptable coin from said resulting signal;
• establishing a criteria for automatically determining when said coil acceptability criteria should be altered from the value of said resulting signal;
• and
• selectively altering said coin acceptability criteria for subsequent determinations of coin acceptability in response to the value of said resulting signal.

In a coin operated apparatus a coin inspecting circuit for dynamically testing the acceptability of coins, comprising:

• means for testing a conductive object to determine whether said conductive object is an acceptable coin in accordance with a predetermined coin acceptability criteria;
• means for determining whether said conductive object is an acceptable coin from the result of said test;
• and
• means for selectively and automatically altering said coin acceptability criteria for a subsequent determination of coin acceptability in response to the result of said test and in accordance with a predetermined criteria for determining when said coin acceptability criteria should be altered.