Dispenser control with ultrasonic position detection

Abstract

A method and apparatus is provided to detect the position of an object, such as a container, within a multidimensional target space above which is a dispensing spigot to dispense water, ice, or other beverage. The dispenser control is also applicable to other applications, for example, dispensing soap in response to the detecting of human hands. The system has a transceiver emitting pulses of ultrasonic waves, a portion of which are reflected by the object in the target space and detected by the transceiver, and a processing circuit for determining the relative strength of the reflected signals and the time it takes an ultrasonic wave to be emitted, reflected, and received by a transceiver. The received signal is checked to determine if the amplitude of the reflected ultrasonic wave is consistent with an object occupying the target space. A timer circuit creates a timing window which further defines the target space. When a reflected ultrasonic wave has large enough amplitude and occurs within the timing window, a dispensing signal is produced. An instant OFF stops dispensing as soon as the object begins to leave the target space, thereby preventing spillage.