Presence Sensor Control Circuit for Low-Power False Trigger Reduction
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Solution Overview
Problem
Existing motion detection systems in sanitary premises, particularly public toilets, face issues with false detections due to reflective surfaces and high energy consumption, limiting their effectiveness and autonomy in high-traffic areas.
Innovation Solution
A double detection control system combining a telemetric sensor with a light sensor and a control circuit that cyclically measures light intensity, switching to a low-power sleep mode in low light and activating a telemetry sensor for precise distance measurement when necessary, thereby reducing energy consumption and false detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an infrared sensor is used for presence detection, then detection capability is improved, but false detections occur due to reflective surfaces and external light sources
Solution Approach 1:
The system segments the detection process into two independent parts: a light sensor for ambient light detection and a rangefinder for distance measurement. Each sensor performs its specific function without interfering with the other, eliminating false detections caused by reflective surfaces while maintaining accurate presence detection through the combination of both measurements.
Solution Approach 2:
The control circuit acts as an intermediary that processes signals from both the light sensor and rangefinder. It integrates the ambient light level information with the distance measurement to make a reliable presence determination, filtering out false signals that would otherwise trigger incorrect actuator activation.
2Reliability
If the infrared sensor operates continuously for presence detection, then detection reliability is improved, but energy consumption increases
Solution Approach 1:
The system implements periodic action by having the control circuit cyclically measure ambient light levels at predetermined intervals rather than continuously operating the rangefinder. The rangefinder is activated only when the light sensor detects a significant change in ambient light, creating a periodic detection pattern that reduces energy consumption while maintaining reliable presence detection.
Solution Approach 2:
The system dynamically adjusts its detection behavior based on ambient light conditions. When the light sensor detects a significant change in light levels, the system transitions from a low-power state to an active detection state, activating the rangefinder only when necessary. This dynamic operation optimizes energy usage while ensuring detection reliability when actually needed.
3Ease of manufacture
If a battery power supply is used to avoid electrical wiring, then installation simplicity is improved, but system autonomy is limited due to high energy consumption
Solution Approach 1:
The system uses periodic action by implementing a duty cycle where the rangefinder operates only during brief measurement intervals rather than continuously. The control circuit cycles between sleep mode and active measurement mode, dramatically reducing average power consumption and extending battery autonomy while maintaining the installation simplicity of using battery power instead of electrical wiring.
Solution Approach 2:
The system discards continuous operation in favor of intermittent operation, recovering energy by putting the rangefinder into sleep mode between measurements. The control circuit manages power distribution to discard unnecessary energy consumption while recovering maximum battery life, enabling the system to operate autonomously for extended periods on battery power.
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 false detections and energy consumption, allowing for reliable and efficient operation of sanitary appliances with extended autonomy in high-traffic environments.
Implementation Method 1
a light sensor (101) and a rangefinder sensor (102)... The control circuit (100) is configured to cyclically measure an intensity of light received by the light sensor (101)
Implementation Method 2
measuring distance using an infrared beam based on the return time principle. This type of detector has the drawback of high energy consumption
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to an electronic control system. The system comprises an infrared rangefinder combined with a light sensor and a control circuit for controlling the actuator, for example, to open and close a solenoid valve for sanitary plumbing or to start or stop a motor such as a pump motor or any other mechanism, upon detection of a user's presence. The control circuit is configured to cyclically perform a light measurement (201) with the light sensor, and, if the measured light intensity is below a first predetermined threshold (S1), for example corresponding to the light intensity of a nightlight, the ambient light intensity measurement frequency is set (208) to a first frequency F1, and the entire control system is then put into sleep mode (207) between two light intensity measurements.