US Patent 7806248 System and method for coin validation

A system for validating a coin has a passageway through which the coin passes, in use; an oscillator having a component positioned relative to the passageway for the frequency and amplitude of oscillation of the oscillator to be varied, in use, by passage of the coin along the passageway; a period (or frequency) determining unit for determining the period (or frequency) of an oscillating signal provided by the oscillator when influenced by the coin and for supplying a determined period (or frequency) value; an amplitude determining unit for determining the amplitude of the oscillating signal provided by the oscillator when influenced by the coin and for supplying a determined amplitude value; and an assessing unit for assessing if the determined period (or frequency) and amplitude values lie in a predetermined window of period (or frequency) and amplitude values.