A vending machine includes a vend sensor for detecting a completion of a vend operation. The vend sensor includes an electronic circuit connected to first and second sound elements positioned on opposing sides of a product delivery chute of the vending machine. The first sound element directs a sound beam across the product delivery chute where it is received by the second sound element. During a vend operation, a product container is guided to the product delivery chute to be dispensed to a consumer. As the container passes through the product delivery chute, the sound beam is interrupted, thereby signaling the completion of a vend operation. Each of the first and second sound elements is provided with a cone that focuses the sound beam so as to limit interruptions stemming from outside sound sources.