Portable Sensor Association Using Motion-Triggered Signal Switching
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Solution Overview
Problem
Existing building management systems require manual intervention for portable sensor devices to associate with new control devices when moved to different rooms, and they suffer from limited energy storage due to frequent communication needs.
Innovation Solution
A method where a portable sensor device automatically associates with a stationary control device by changing signal frequency based on movement detection, allowing it to conserve energy by communicating at longer intervals when stationary and more frequently when moved, using a motion detector and signal strength analysis to determine association with the closest control device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the portable sensor device transmits signals frequently to detect movement and enable automatic association, then the association accuracy and automation level improve, but the energy consumption increases
Solution Approach 1:
The system dynamically adjusts the transmission frequency of the portable sensor device based on its operational state. When movement is detected, the device transmits signals at a higher frequency (second frequency) to enable accurate tracking and association. When stationary, it switches to a lower frequency (first frequency) to conserve energy. This dynamic adaptation resolves the contradiction between automation performance and energy consumption.
Solution Approach 2:
The invention changes the transmission frequency parameter of the portable sensor device according to its movement state. By switching between first frequency (low power mode) and second frequency (high precision mode), the system optimizes the balance between association accuracy and energy usage, eliminating the need for manual intervention while preserving battery life.
2Speed
If the portable sensor device uses high transmission frequency to quickly associate with control devices, then the association speed improves, but the battery life decreases
Solution Approach 1:
The system employs periodic transmission with variable periods. During the association process, when movement is detected, the transmission period is shortened (higher frequency) to achieve quick association. Once associated and stationary, the transmission period is extended (lower frequency) to minimize energy consumption. This periodic action with adaptive timing resolves the contradiction between association speed and battery life.
3Loss of energy
If the portable sensor device remains in energy-saving mode, then the energy consumption decreases, but the detection of movement and room changes becomes slower
Solution Approach 1:
The system uses feedback from signal strength measurements to determine when to switch between energy-saving mode and active detection mode. When the portable device is stationary, low-frequency transmissions provide feedback confirming stable association. When movement occurs, signal strength variations trigger increased transmission frequency, enabling rapid detection of room changes while minimizing overall energy consumption through intelligent mode switching.
Data Source
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AI summary
There is provided a building management system and a method for associating a portable sensor device with a stationary control device in such a system. Upon detection of a movement of the portable sensor device, the portable sensor device starts to transmit signals more frequently to the stationary control devices. It is determined that the movement of the portable sensor device has stopped if the signal strength of the transmitted signals received at the stationary control devices is essentially constant during a time window. In response to such a determination, the portable sensor device is associated with the stationary control device having the highest received signal strength and the portable sensor device returns to an energy-saving mode.