Mobile-Body Detection Device Power Management via Doppler Signal Gating
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Solution Overview
Problem
Conventional moving body detection devices face challenges in reducing power consumption while maintaining accuracy, especially when operated intermittently, as they struggle to stabilize circuit operations quickly, leading to potential false detections.
Innovation Solution
A moving body detection device with a control portion that periodically switches between halt and detection modes, only activating the transmitter and phase detection portion when a Doppler signal is detected, and using dual phase detection blocks with low and high pass filters to isolate the Doppler signal, thereby reducing power consumption and minimizing false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the moving body detection device operates intermittently to reduce power consumption, then power consumption is reduced, but detection accuracy deteriorates due to circuit instability and false detections
Solution Approach 1:
The system performs preliminary actions by pre-heating or stabilizing the circuit before detection, ensuring that the circuit reaches a stable state before actual detection begins. This preliminary stabilization prevents false detections while allowing the system to remain in a low-power state otherwise.
Solution Approach 2:
The detection device operates in periodic cycles with distinct phases: a stable state for power saving, and an active detection state for monitoring. By periodically switching between these states and ensuring proper circuit stabilization during transitions, the system achieves both low power consumption and reliable detection.
2Reliability
If the transmitter and phase detection portion operate continuously to ensure stable detection, then detection accuracy is maintained, but power consumption increases
Solution Approach 1:
Instead of continuous operation, the transmitter and phase detection portion operate periodically in synchronized cycles. The system transitions between active detection phases and stable low-power phases, reducing overall power consumption while maintaining detection capability through strategic periodic activation.
Solution Approach 2:
The system prepares the circuit in advance during the stable phase, ensuring all components are properly initialized and stabilized before activation. This preliminary preparation allows for quick, reliable transitions to the active detection state without requiring continuous operation.
3Productivity
If the moving body determination portion operates during circuit stabilization period to maximize detection coverage, then detection coverage is improved, but false detections increase due to unstable circuit operations
Solution Approach 1:
The system performs necessary circuit stabilization and initialization actions before the moving body determination portion begins operation. This preliminary stabilization ensures that the circuit is in a reliable state, preventing false detections while allowing the determination portion to operate with high accuracy.
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 power consumption while maintaining detection accuracy by ensuring the moving body determination portion only operates when a Doppler signal is present, stabilizing circuit operations and minimizing erroneous detections.
Implementation Method 1
The transmitter receives the first oscillation signal that is outputted from one output end of the oscillation circuit, and transmits an ultrasonic wave having a frequency that is equal to the oscillation frequency
Implementation Method 2
The receiver receives an ultrasonic wave that comes from the monitoring space, converts the ultrasonic wave into an electric signal (reception signal)
Implementation Method 3
detects a frequency shift, of a reflected wave, that is generated by a movement of an object inside the monitoring space
Data Source
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AI summary
A moving body detection device includes an oscillation circuit, a transmitter, a receiver, a phase detection portion, a moving body determination portion, and a control portion. The control portion is configured to periodically switch between a halt mode of causing at least the transmitter and the phase detection portion to halt and a detection mode of causing the transmitter and the phase detection portion to operate. Also, the control portion is configured to, in the detection mode, determine whether or not the Doppler signal is outputted from the phase detection portion in a period from a point of time when a predetermined waiting time elapses from a start point of the detection mode until the detection mode ends. Then, the control portion is configured to, upon determining that the Doppler signal is outputted, extend the detection mode and cause the moving body determination portion to operate, and upon determining that the Doppler signal is not outputted, switch to the halt mode.