Multi-Threshold Infrared Sensor Alarm Triggering
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Solution Overview
Problem
Existing infrared motion sensors face false alarms due to varying infrared radiation magnitudes from different objects and ambient conditions, as they rely on a single fixed threshold for detection.
Innovation Solution
Implementing multiple thresholds, including a first determination threshold, a second determination threshold greater than the first, and a time determination threshold, to determine whether a sensor signal satisfies alarm conditions, thereby reducing false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single fixed threshold is used for detection, then the device complexity is low, but false alarms increase due to varying infrared radiation magnitudes from different objects and ambient conditions
Solution Approach 1:
The single fixed threshold is segmented into multiple thresholds (first determination threshold, second determination threshold, third determination threshold) with different sensitivity levels. Each threshold serves a specific detection purpose, allowing the system to distinguish between different types of targets and reduce false alarms while maintaining manageable complexity through structured segmentation.
Solution Approach 2:
The threshold parameter is changed from a single fixed value to multiple variable values with different magnitudes. The system dynamically selects and adjusts threshold parameters based on detection needs, transforming the static threshold into a flexible multi-level parameter system that adapts to different detection scenarios.
2Reliability
If multiple thresholds are used for detection, then false alarms are reduced, but the device complexity increases
Solution Approach 1:
The determination logic is made dynamic through time-based adaptation. The system transitions from static threshold comparison to dynamic multi-stage determination that evolves over time. The first determination threshold is used initially, and based on time duration and signal persistence, the system dynamically progresses to second and third thresholds, creating an adaptive detection flow that reduces false alarms while managing complexity through temporal dynamics.
Solution Approach 2:
The system performs preliminary determination using the first determination threshold before proceeding to more complex evaluations. This preliminary action filters out obvious false alarms early in the process, allowing the system to reserve more complex determination logic for cases that truly require it, thereby managing overall system complexity while maintaining high alarm accuracy.
3Measurement precision
If a single determination approach is used, then the processing speed is fast, but the detection precision decreases due to inability to distinguish different target types
Solution Approach 1:
The single determination approach is segmented into multiple determination stages (first determination, second determination, third determination) with increasing precision. Each stage handles specific aspects of target identification, allowing the system to achieve high measurement precision through structured segmentation while maintaining processing speed by filtering candidates through progressive stages.
Solution Approach 2:
The system applies partial determination actions at each stage rather than performing complete analysis on all signals. The first determination threshold performs a quick partial check, and only signals that pass this partial action proceed to more thorough determination stages, thereby maintaining overall processing speed while achieving high precision for confirmed targets.
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 effectively reduces false alarms by adjusting sensitivity based on signal magnitude and duration, ensuring more precise detection of alarm states.
Implementation Method 1
a passive infrared sensor (PIR) that absorbs an infrared radiation signal from an external object through a Fresnel lens on the surface of the sensor itself and generates an analog signal
Implementation Method 2
absorbs an infrared radiation signal from an external object through a Fresnel lens on the surface of the sensor itself
Data Source
AI summary
An alarm triggering method for a sensor and an electronic device using the same are proposed. The method is applicable to an electronic device and includes the following steps. A sensor signal is received from the sensor. Whether a signal magnitude of the sensor signal satisfies a first triggering condition associated with a first determination threshold is determined. In response to the signal magnitude satisfying the first triggering condition, whether the signal magnitude satisfies a second triggering condition associated with a second determination threshold or a third triggering condition associated with a time determination threshold is further determined, where the second determination threshold is greater than the first determination threshold. When the signal magnitude satisfies the second triggering condition or the third triggering condition, the sensor is determined to be in an alarm state so as to output an alarm signal.