Abstract: The present invention provides for a vending system wherein a monitoring system verifies that a product ordered by a vending customer is actually delivered through a delivery area to the customer. If the product ordered is unavailable either because of an out of stock situation or a blockage of the delivery path for that product, the present invention allows the customer to request a refund or order a second product. Additionally, the present invention helps to prevent theft of product from the vending system.

Abstract: The present invention provides for a vending system wherein a monitoring system verifies that a product ordered by a vending customer is actually delivered through a delivery area to the customer. If the product ordered is unavailable either because of an out of stock situation or a blockage of the delivery path for that product, the present invention allows the customer to request a refund or order a second product. Additionally, the present invention helps to prevent theft of product from the vending system.

Abstract: An optical vend sensing system for use in vending machines employs a row of light emitters on one side of a region through which a vend product passes during delivery and a row of light detectors on the opposite side. Each detector is substantially aligned with a corresponding one of the emitters, and is capable of receiving light from any of more than one of the emitters when that emitter is activated. The emitters are individually activated in sequential, round-robin fashion and multiple detectors are monitored for each emitter when activated. Interruption of detectible beams between an activated emitter and one of the multiple emitters monitored for the activated emitter. Power applied to an activated emitter is calibrated in steps to a minimum level sufficient to ensure detection by all monitored detectors of light emitted by an activated emitter, plus a safety margin.

Abstract: A frequency measuring device measures the number of full cycles of a periodically time varying signal which occurs in a fixed sampling period and calculates the fraction of a cycle of the signal occurring in the sampling period.