Home Automation Motion Sensing With Adaptive Orientation Tracking
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Solution Overview
Problem
Existing home automation devices struggle to reliably discriminate between different types of movement of monitored objects, such as doors or windows, to determine whether a break-in has occurred, due to high energy consumption and lack of precision in existing sensors like magnetometers and accelerometers.
Innovation Solution
A movement detector system that uses a combination of low-frequency orientation signals and high-frequency acceleration signals, with adjustable sampling frequencies to conserve energy and improve detection accuracy, including a processing unit that compares initial and final orientations and displacement energy to determine the type and intensity of movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetometers are used for detecting orientation changes, then measurement precision is improved, but use of energy increases significantly
Solution Approach 1:
The system dynamically adjusts the sampling frequency of the magnetometer based on detected activity. During normal operation, the magnetometer operates at a low sampling frequency to conserve energy. When acceleration sensors detect movement or potential intrusion activity, the system automatically increases the magnetometer's sampling frequency to high levels for precise orientation tracking, then reduces it again when activity ceases.
Solution Approach 2:
The invention changes the operational parameters of the magnetometer by implementing variable sampling frequencies. The system transitions between different operational states (low-power mode and high-precision mode) by adjusting the sampling rate parameter, allowing the device to maintain measurement capability while optimizing energy consumption based on actual detection needs.
2Device complexity
If accelerometer signals are used alone for detecting movement, then device complexity is reduced, but measurement precision deteriorates due to inability to distinguish movement types
Solution Approach 1:
The system merges data from two different sensor types (accelerometer and magnetometer) to achieve comprehensive movement detection. The accelerometer provides information about linear acceleration and impact forces, while the magnetometer detects orientation changes. By combining these complementary data sources, the system can accurately distinguish between different movement types such as door opening, window breaking, or object displacement, overcoming the limitations of using either sensor alone.
Solution Approach 2:
The processing unit acts as an intermediary that integrates and analyzes signals from both the accelerometer and magnetometer. It correlates data from both sensors to determine whether detected movements represent actual intrusions or normal environmental variations, thereby improving measurement precision without significantly increasing overall system complexity.
3Measurement precision
If high sampling frequency is used for both orientation and acceleration signals, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The system implements dynamic frequency adjustment where the sampling rate of the magnetometer is changed based on system state. During idle periods, the magnetometer operates at a low sampling frequency (e.g., 10 Hz or lower) to minimize energy consumption. When the accelerometer detects activity indicative of potential intrusion, the system dynamically increases the magnetometer's sampling frequency to a high rate (e.g., 100 Hz or higher) to capture precise orientation data, then reduces it again when activity subsides.
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 achieves reliable discrimination between types of movement, reduces energy consumption, and accurately determines the position and displacement of monitored objects, enabling effective detection of break-ins while maintaining low power usage.
Implementation Method 1
an orientation sensor (including a magnetometer) fixed to the housing and adapted to provide orientation signals representative of changes in the instantaneous orientation of at least one fixed direction of the housing with respect to a local terrestrial magnetic field
Implementation Method 2
an accelerometer adapted to provide acceleration signals representative of instantaneous acceleration measurements
Data Source
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AI summary
The invention relates to a home-automation device comprising a detector of displacement of a monitored object, an accelerometer, an orientation sensor, a memory, a processing unit, characterized in that the processing unit is programmed to, on detection of an event, acquire the orientation, wait for a waiting period and then acquire the instantaneous final orientation, and calculate an energy of displacement of the detector on the basis of the acceleration signals acquired in the waiting duration.