Remote Ultrasonic Occupancy Sensor Segmentation
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Solution Overview
Problem
Occupancy sensors installed without a neutral AC connection face power limitations due to reliance on ground leakage current, restricting their sensing range and performance, especially when using active sensing technologies like ultrasonic sensors.
Innovation Solution
The occupancy sensor system separates the high-power transmitter and low-power receiver portions, with the transmitter connected to a standard AC power source (hot and neutral) and the receiver powered by ground leakage current, allowing for greater energy transmission and detection of occupancy without direct access to the original transmitted waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the transmitter and receiver are co-located in the same device, then the receiver can directly access the original transmitted waveform for accurate occupancy detection, but the power available from ground leakage current is insufficient to support adequate transmission energy for large space monitoring
Solution Approach 1:
The occupancy sensor is divided into two separate units: a transmitter unit and a receiver unit. The transmitter unit generates ultrasonic waves and can be powered by a higher-power source, while the receiver unit detects reflected waves and is powered by ground leakage current. This segmentation allows each unit to be optimized for its specific function and power constraints, resolving the contradiction between transmission power needs and receiver power limitations.
Solution Approach 2:
The patent introduces a signal estimation mechanism where the receiver generates an estimate of the transmitted waveform based on received signals from other transmitters. This intermediary approach allows the receiver to operate without direct access to the original transmitted waveform, enabling remote transmitter-receiver configuration while maintaining detection accuracy through comparative analysis of estimated versus actual received signals.
2Area of stationary object
If the transmitter uses higher power to monitor larger spaces, then the sensing range is improved, but the ground leakage current limitation of 500 microamperes cannot support the required power transmission
Solution Approach 1:
By separating the high-power transmitter function from the low-power receiver function into different physical units, the system allows the transmitter to potentially access higher power sources while the receiver operates within ground leakage current limits. This enables coverage of larger areas without exceeding safety standards for ground leakage current.
Solution Approach 2:
The receiver creates an estimate or copy of the transmitted waveform signal based on reflections and communications from transmitter units. This copying mechanism allows the receiver to perform accurate occupancy detection without needing direct access to the high-power original transmitted waveform, enabling the system to scale to larger monitored areas while maintaining detection precision.
3Power
If the receiver is located remotely from the transmitter, then the transmitter can be positioned where higher power is available, but the receiver must detect occupancy without direct access to the original transmitted waveform
Solution Approach 1:
The patent introduces signal estimation as an intermediary process where the receiver generates an approximate copy of the transmitted waveform based on received signals. This estimation mechanism bridges the gap between remote transmitter-receiver configuration and the need for waveform access, allowing the receiver to perform accurate occupancy detection through comparison of estimated versus actual received signals, thereby managing the added complexity through a systematic estimation-comparison approach.
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 configuration enables a wider sensing range and improved performance by providing adequate power to the transmitter while the receiver can accurately detect occupancy using signal estimation and comparison, overcoming the limitations of no-neutral installations.
Implementation Method 1
The transmitter portion (110) includes an oscillator (204) configured to generate an ultrasonic signal
Implementation Method 2
Ultrasonic sensors operate by detecting a Doppler frequency shift between the transmitted and received signals. Doppler frequency shifts are generated by the ultrasonic energy that is reflected off of a moving object in the space.
Implementation Method 3
Ultrasonic sensors operate by detecting a Doppler frequency shift between the transmitted and received signals. The magnitude of the frequency shift is proportional to speed of the moving object.
Implementation Method 4
The sensor then uses a receiver to collect the reflected energy and analyze it for signs of occupancy within the space.
Data Source
AI summary
An occupancy sensor device for monitoring a space includes a transmitter portion and a receiver portion. The receiver portion is located remotely from the transmitter portion. To enable reliable detection of occupancy within the monitored space, an estimate of the signal transmitted by the active sensor in the transmitter portion is compared to the signal received by the transmitted portion.