Adaptive Motion Detector Follow-Up Time Control
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Solution Overview
Problem
Conventional presence detectors often keep lights on for extended periods even if a person's presence in the monitored area is brief, leading to unnecessary energy consumption, as they primarily adjust follow-up times based on empirical values and trigger frequency without immediate reaction to short-term presences.
Innovation Solution
A method that determines an assumed length of stay through a test interval, comparing it with a maximum length of stay, and switches off the load current if the presence is deemed short-term, allowing for immediate detection and response to brief presences by setting a new follow-up time with each trigger signal and using user-defined and environmental parameters to control lighting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the follow-up time is extended to ensure lighting remains on during interruptions in motion detection, then the reliability of lighting continuity is improved, but the energy consumption increases when presence is only short-term
Solution Approach 1:
The patent applies dynamics by making the follow-up time adjustable and adaptive rather than fixed. The control unit modifies the follow-up time based on the frequency of trigger signals detected during a test interval, allowing the system to dynamically adapt between long follow-up times (for reliable continuity) and short follow-up times (for energy saving) depending on actual usage patterns
Solution Approach 2:
The patent changes the parameter of follow-up time based on measured trigger signal frequency. During a test interval, the control unit counts trigger signals and compares the frequency to reference values, then adjusts the follow-up time parameter accordingly - extending it when frequent motion is detected and shortening it when motion is infrequent, thereby resolving the contradiction between reliability and energy consumption
2Adaptability or versatility
If the follow-up time is automatically adjusted based on empirical trigger frequency values, then the adaptability to usage patterns is improved, but the response time to short-term presences increases due to measurement periods
Solution Approach 1:
The patent implements preliminary action by conducting a test interval at the beginning to detect motion patterns before the normal follow-up time takes full effect. This preliminary measurement period allows the system to pre-adjust the follow-up time parameter based on observed trigger frequency, so that when actual presence detection occurs, the system is already optimized and can respond immediately without waiting for extended measurement periods
Solution Approach 2:
The patent uses periodic action by implementing regular test intervals during which trigger signal frequency is measured and the follow-up time is adjusted. This periodic monitoring and adjustment mechanism allows the system to continuously adapt to changing usage patterns while maintaining responsive behavior, balancing adaptability with timely response to presences
3Speed
If the light is switched on immediately upon detecting a trigger signal, then the responsiveness to presence is improved, but the energy consumption increases when presence is only brief
Solution Approach 1:
The patent changes the follow-up time parameter based on trigger signal frequency measured during a test interval. When the frequency exceeds a reference value (indicating prolonged presence), the follow-up time is extended and lighting is switched on immediately. When the frequency is below the reference value (indicating brief presence), the follow-up time is shortened, allowing the system to maintain responsiveness while avoiding unnecessary energy consumption from extended lighting during brief presences
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
This approach ensures that lights are not left on for the entire follow-up time when presence is short, effectively saving energy by promptly switching off the lighting current when a person's presence is determined to be brief, thereby optimizing energy usage.
Implementation Method 1
They measure and compare the infrared radiation in their detection range, but do not emit any radiation themselves
Implementation Method 2
Pyroelectric sensors are preferred for an embodiment of the presence detector as a passive IR presence detector
Data Source
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AI summary
The method involves determining trigger signals (11.1-11.3) for controlling load current by processing and converting motion signals (A). Expected stopping duration (ta) is determined based on the determined trigger signals during a test interval (tt), where the interval is shorter than duration (tn) of stopping time (13). The determined stopping duration is compared with preset maximum stopping duration (tamax), and the current is switched off during the interval when the current is switched on and the determined stopping duration is smaller than the maximum stopping duration. An independent claim is also included for a motion detector comprising a detection unit for detecting motion signals produced by movement of persons in a detection region.