Pulsed Faucet Sensor Control for False Trigger Rejection
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Solution Overview
Problem
Existing contactless control systems for faucets are prone to false positives and false triggering due to changes in ambient light and reflections from nearby surfaces, leading to unintended faucet operation, water wastage, and maintenance issues.
Innovation Solution
A control system for fluid delivery devices that includes an emitter to emit a series of pulses of electromagnetic radiation, a detector to detect reflected pulses, and a microprocessor to analyze samples of signals from the detector, generating control signals only if the analysis matches pre-determined patterns, thereby reducing false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a contactless control system using electromagnetic radiation detection is implemented, then manual contact hygiene is improved, but false positives and false triggering occur due to ambient light changes and reflections
Solution Approach 1:
The system emits electromagnetic radiation in periodic pulse sequences rather than continuously. By analyzing the temporal pattern of reflected pulses and comparing expected versus actual return signals, the system can distinguish between genuine hand presence and false triggers caused by ambient light changes or reflections from stationary surfaces.
Solution Approach 2:
The detector provides feedback signals to the controller about the detected electromagnetic radiation. The controller uses this feedback to compare expected pulse patterns with actual detected patterns, enabling it to identify and reject false positives while maintaining accurate detection of genuine hand presence.
2Device complexity
If single pulse detection is used for simplicity, then device complexity is reduced, but measurement precision and reliability deteriorate due to false positives
Solution Approach 1:
Instead of detecting single isolated pulses, the system employs periodic pulse sequences with known temporal characteristics. The controller expects specific patterns of reflected pulses and compares actual detections against these expectations, significantly improving detection accuracy without requiring overly complex hardware.
Solution Approach 2:
The controller pre-programmes the expected temporal patterns of pulse reflections from hand presence. By having these reference patterns established beforehand, the system can quickly compare actual detections against known good patterns, achieving high measurement precision through simple pattern matching rather than complex real-time analysis.
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 system effectively reduces the likelihood of false positives and unintended faucet operation, minimizing water wastage and maintenance needs by ensuring accurate detection of user presence.
Implementation Method 1
a detector operable to detect as a series of detection events electromagnetic radiation pulses reflected by an object on which the emitted pulses of electromagnetic radiation are incident
Data Source
AI summary
A control system is provided for a fluid delivery device. The control system includes an emitter operable to emit a series of pulses of electromagnetic radiation, as well as a detector operable to detect as a series of detection events electromagnetic radiation pulses reflected by an object on which the emitted pulses of electromagnetic radiation are incident. The control system also includes a microprocessor operable to receive signals corresponding to each detection event from the detector, and to analyse a series of samples of the signals received from the detector. Each sample corresponds to a plurality of successive detection events. The microprocessor is also operable to subsequently generate one or more signals to control operation of the fluid delivery device depending on the results of the analysis.