US Patent 9976291 Faucet including capacitive and ultrasonic sensing

A fluid delivery apparatus includes a spout, an ultrasonic sensor, and a capacitive sensor. The ultrasonic sensor is configured to detect the presence of a user adjacent the spout when enabled. The capacitive sensor is configured to define a capacitance sensing field in an area near the spout and also to detect a presence of a user. A controller is coupled to the capacitive sensor and the ultrasonic sensor. The controller is programmed to detect the presence of a user in the capacitance sensing field based on an output signal from the capacitance sensor. The controller is also programmed to enable the ultrasonic sensor in response to detecting the presence of the user in the capacitance sensing field with the capacitive sensor, thereby reducing the amount of power used by the ultrasonic sensor.