Dual-Purpose PIR Sensor Dwell Timing for Occupancy and Security
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Solution Overview
Problem
Home security systems face issues with false alarms from motion sensors due to voltage fluctuations and interference, and occupancy sensors have shorter battery life and lack a restore command, making them unsuitable for dual-purpose use.
Innovation Solution
A dual-purpose sensor that functions as both a security motion sensor and an occupancy sensor, transmitting a restore command after detecting motion and an unoccupied signal after a dwell time, with adjustable dwell times to optimize battery life and reduce false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion sensors transmit signals frequently to ensure accurate occupancy detection, then occupancy detection accuracy is improved, but battery life deteriorates
Solution Approach 1:
The patent implements a dwell time mechanism that limits signal transmissions to once per predetermined time period. The processor is configured to prevent additional transmissions during the dwell time window, creating a periodic transmission pattern that conserves battery power while maintaining acceptable occupancy detection accuracy.
2Reliability
If motion sensors do not transmit restore command immediately after motion detection, then false alarms are reduced, but system response time deteriorates
Solution Approach 1:
The patent transmits the restore command in advance during the dwell time period after motion detection. This preliminary action allows the security system to be armed before the dwell time expires, eliminating the need to wait for dwell time completion while preventing false alarms by maintaining the no-transmission restriction during the critical detection window.
3Measurement precision
If occupancy sensors are used instead of motion sensors, then battery life is reduced due to frequent transmissions, but occupancy detection capability is improved
Solution Approach 1:
The patent creates a dual-purpose sensor that combines both motion detection and occupancy detection capabilities in a single device. The pyroelectric infrared sensor can operate in different modes: transmitting immediately for security applications or using dwell time for occupancy monitoring, making the device universally applicable to both security and automation functions.
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 dual-purpose sensor enhances battery life and reduces false alarms by minimizing unnecessary transmissions, allowing seamless integration with home automation and security systems.
Implementation Method 1
Motion sensors typically comprise a pyroelectric infrared sensor that is sensitive to changes in voltage and current
Data Source
AI summary
A system, method and apparatus for detecting the presence of a person in an area monitored by an electronic person detector that may operate both as a security motion sensor and a home automation occupancy sensor.