Electronic Faucet TOF Sensing for Reliable Flow Termination
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Solution Overview
Problem
Existing automatic touchless faucets with optical sensors face challenges in consistent and repeatable triggering due to variations in reflectivity of objects based on color, texture, glossiness, and size, leading to false positives and negatives.
Innovation Solution
Employing a time-of-flight (TOF) sensor aimed directly at the stream of water from the discharge outlet to detect the presence or absence of an object within a shaped and limited detection zone, independent of water flow, using a TOF sensor signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple trigger level is used for optical sensor detection, then the device complexity is reduced, but the reliability of detection deteriorates due to false positives and false negatives caused by variations in object reflectivity
Solution Approach 1:
The patent changes the detection parameter from reflectivity-based optical sensing to time-of-flight-based distance measurement. This fundamental parameter change allows the system to detect objects based on their spatial position relative to the faucet rather than their optical properties, eliminating false detections caused by varying reflectivity while maintaining simple control logic.
2Adaptability or versatility
If the sensor detection zone covers a large area to detect objects from various positions, then the adaptability is improved, but the measurement precision deteriorates due to inability to distinguish between objects at different distances
Solution Approach 1:
The patent implements dynamic detection zone adjustment where the sensor actively measures distance to objects and the system adapts its detection criteria based on the measured distance. The detection zone is not static but dynamically adjusted according to the calculated distance, allowing the system to maintain precision while covering various object positions.
Solution Approach 2:
The patent adds the distance dimension to the detection process by using time-of-flight measurement. Instead of only detecting whether an object is present in a 2D detection zone, the system now measures the 3D distance to the object, enabling precise spatial discrimination while maintaining broad detection coverage.
3Reliability
If the sensor aims at the water stream to detect object absence during flow, then the reliability of flow termination detection is improved, but the device complexity increases due to coordinated sensor and valve control
Solution Approach 1:
The patent merges the detection function and the control function into a coordinated system where the time-of-flight sensor and electronically controlled valve work as an integrated unit. The sensor aims at the water stream to detect object absence, and this detection directly controls the valve state, creating a unified system that reliably terminates flow when no object is detected.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The TOF sensor effectively detects the absence of a hand or object while water is streaming, reducing false activations and ensuring reliable water control.
Implementation Method 1
a time-of-flight (TOF) sensor in electrical communication with the processor and operably connected to the faucet body and positioned to transmit a sensing signal toward the expected fluid flow volume in a sensing signal volume
Data Source
AI summary
The present application discloses electronic plumbing fixture fittings, such as electronic faucets, with a shaped and limited sensor detection zone. Exemplary embodiments include devices with a plurality of overlapping sensors and devices with a single time-of-flight (TOF) sensor capable of detecting the presence or absence of an object whether or not water is flowing out of a discharge outlet in the in a TOF detection zone.