Abstract: A pilot valve has: an input passageway, an output passageway, a rotatable shaft disposed between them, a permanent magnet affixed to the rotatable shaft, an electromagnet, a control element, and a failsafe magnet. The rotatable shaft has a slot that gives the rotatable shaft a varied cross-section as a function of its position. The slot is disposed to permit fluid to flow between the input passageway and the output passageway except when the rotatable shaft is in a closed position. The electromagnet is disposed to generate first magnetic field that, via the permanent magnet, drives the rotatable shaft away from the closed position. The control element places a PWM current on the electromagnet, such that the length of the duty cycle controls the strength of the first magnetic field. The failsafe magnet is disposed to generate a second magnetic field that drives the rotatable shaft away from the closed position.

Abstract: An electronic faucet having a spout, a electronically actuated valve, and a microprocessor-based control circuit for operating the valve to enable or disable water flow through the spout. The microprocessor has a control program which includes a calibration routine that uses an infra-red sensor to determine an adjustable setpoint indicative of the signal received from the sensor in the absence of an object in front of the faucet. The microprocessor switches the valve from its closed state to its open state when the signal from the sensor either increases above the setpoint by a selected amount or decreases below the setpoint by a selected amount. This provides a window about the setpoint within which differences between the setpoint and the signal do not result in opening of the valve. Object detection is accomplished using a tracking routine that adjusts the setpoint in an attempt to track the sensor signal.

Abstract: An electronic faucet having a spout, a electronically actuated valve, and a microprocessor-based control circuit for operating the valve to enable or disable water flow through the spout. The microprocessor has a control program which includes a calibration routine that uses an infra-red sensor to determine an adjustable setpoint indicative of the signal received from the sensor in the absence of an object in front of the faucet. The microprocessor switches the valve from its closed state to its open state when the signal from the sensor either increases above the setpoint by a selected amount or decreases below the setpoint by a selected amount. This provides a window about the setpoint within which differences between the setpoint and the signal do not result in opening of the valve. Object detection is accomplished using a tracking routine that adjusts the setpoint in an attempt to track the sensor signal.