SENSOR FOR DETECTING THICKNESS OF ITEMS

摘要

A method and system for detecting a presence of more than one item at a point along a conveyance path, comprising steps of (A) generating a light beam and directing the beam through the path such that a presence of the item will cause the beam to be attenuated; (B) detecting the beam after it is attenuated by the presence of the item; and (C) determining from the amount of attenuation how many items are simultaneously present. In the preferred embodiment the item is an item of currency (12), and the step of generating a light beam includes a step of operating an optical source (16), such as an LED or a laser, to generate a beam having a wavelength in the range of about 400 nm to about 1 micrometer or longer.