| 摘要 |
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. If the sensor signal undergoes a change that is too large to be tracked, then the microprocessor switches on the valve. Once the sensor signal drops back into a range of values about a stored calibration point, the valve is closed. The control circuit is part of an electronics module that is mounted within the spout and that is held in place between the spout tube and the spout housing. The module includes a curved recess having a shape that conforms to the spout tube so that the module is retained in place at its upper end by the spout tube.
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