RTC Oscillator Detection for Human Presence Verification
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Solution Overview
Problem
Conventional motion-detection systems, such as those based on passive infrared (PIR) sensors, struggle to reliably distinguish between humans and other heated objects like animals due to their inability to detect the presence of electronic devices.
Innovation Solution
A detection system combining a motion detector and an oscillator detector, specifically tuned to the frequency of real-time clock (RTC) devices, is used to enhance reliability by detecting the presence of RTC devices, which are often carried by humans, thereby confirming the presence of a human.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If clock oscillator detection is performed during device initialization, then boot time is reduced, but detection accuracy may be compromised due to insufficient warm-up period
Solution Approach 1:
The system performs preliminary detection of the clock oscillator signal during device initialization before the crystal fully warms up. This preliminary action allows the device to start up quickly while the more accurate detection is deferred to a later time when the oscillator has stabilized.
Solution Approach 2:
The system performs periodic detection of the clock oscillator signal at different time points - first during initialization for quick detection, and then again after a warm-up period for accurate detection. This periodic approach balances speed and accuracy requirements.
2Measurement precision
If detection is delayed until after warm-up period, then detection accuracy is improved, but boot time increases
Solution Approach 1:
The system performs preliminary detection of the clock oscillator signal during device initialization before the crystal fully warms up. This preliminary action allows the device to start up quickly while the more accurate detection is deferred to a later time when the oscillator has stabilized.
Solution Approach 2:
The system performs periodic detection of the clock oscillator signal at different time points - first during initialization for quick detection, and then again after a warm-up period for accurate detection. This periodic approach balances speed and accuracy requirements.
3Stability of the object's composition
If external crystal oscillator is used, then signal stability is improved, but device complexity increases
Solution Approach 1:
The system uses the processor's internal circuitry to detect and evaluate the clock oscillator signal rather than requiring separate external detection circuits. This self-service approach maintains signal stability while reducing device complexity by eliminating redundant components.
Solution Approach 2:
The processor is designed to perform multiple functions including both processing operations and clock oscillator detection. This multi-functionality allows the same hardware to serve dual purposes, reducing overall device complexity while maintaining signal stability.
Data Source
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AI summary
Motion-detection systems are often used to detect presence of humans. Such motion-detection systems are often based on passive infrared (PIR) sensors. Unfortunately, such detection systems are unable to reliably distinguish between humans and other entities such as animals and moving heat sources. To address this issue, it is proposed to detect a presence of real time clock (RTC) devices in addition to detecting the heat sources to better determine whether a detected entity is a human.