Ultrasonic Occupancy Sensor Amplitude Control for False Activation Reduction
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Solution Overview
Problem
Active ultrasonic room occupancy sensors with fixed amplitude transmitters often result in inappropriate activations due to excessive coverage areas and sensitivity issues, leading to unnecessary energy reflections and noise interference.
Innovation Solution
The implementation of an adjustable voltage regulator controlled by a microcontroller to adjust the amplitude of power applied to both the transmitter and receiver, allowing for controlled zone coverage and sensitivity, thereby reducing unnecessary activations and improving signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed amplitude transmitter is used, then transmitter output is stable, but coverage area is too large causing inappropriate activations
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed amplitude transmitter to a dynamically adjustable amplitude transmitter. The microcontroller controls the voltage regulator to adjust the transmitter amplitude in real-time based on the monitored space requirements, enabling the system to adapt to different coverage areas and eliminate inappropriate activations while maintaining operational stability.
Solution Approach 2:
The patent changes the amplitude parameter of the transmitter from a fixed value to an adjustable range. By controlling the voltage regulator to vary the transmitter amplitude between different levels, the system can optimize coverage area and reduce inappropriate activations caused by excessive sensitivity to distant targets.
2Area of stationary object
If high transmitter power is applied, then zone coverage is extended, but internal system noise increases
Solution Approach 1:
The system dynamically adjusts transmitter power levels based on the required coverage area. The microcontroller controls the voltage regulator to apply only the necessary power to achieve the desired zone coverage, avoiding excessive power that would generate internal system noise while still maintaining adequate coverage.
Solution Approach 2:
The patent changes the power parameter from a fixed high level to an adjustable level. By optimizing the transmitter power parameter to match the actual coverage requirements, the system extends zone coverage when needed while minimizing internal system noise generation during normal operation.
3Measurement precision
If receiver sensitivity is increased, then detection capability is improved, but inappropriate activations increase
Solution Approach 1:
The patent applies dynamics by making the receiver sensitivity adjustable rather than fixed. The microcontroller controls the voltage regulator to adjust the receiver amplitude based on the actual detection requirements, enabling the system to maintain high detection capability for legitimate targets while reducing sensitivity to spurious signals that cause inappropriate activations.
Solution Approach 2:
The patent changes the receiver sensitivity parameter from a fixed high value to an adjustable value. By optimizing the receiver amplitude parameter, the system achieves improved detection capability for actual occupancy while minimizing inappropriate activations caused by excessive sensitivity to distant or spurious targets.
4Power
If high power is applied to receiver input, then signal amplitude is increased, but input noise level increases
Solution Approach 1:
The patent changes the receiver input power parameter from a fixed high level to an adjustable level. By optimizing the power applied to the receiver input, the system increases signal amplitude for legitimate detections while minimizing input noise level, thereby improving the overall signal-to-noise ratio.
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 solution effectively minimizes inappropriate sensor activations and internal noise, enhancing the performance of ultrasonic occupancy sensors by tailoring energy output to specific areas and reducing power consumption and heat generation.
Implementation Method 1
an ultrasonic transmitter having an output with a fixed amplitude
Implementation Method 2
The sensitivity of the receiver is often ineffective in minimizing inappropriate activations
Data Source
AI summary
An active ultrasonic room occupancy sensor with the output amplitude of the transmitter controlled by the amplitude of power applied to the transmitter to control the zone of coverage for a sensor. An adjustable voltage regulator under control of a microcontroller applies controlled amplitude voltage to the transmitter to adjust the output amplitude of the transmitter. The adjustable amplitude transmitter allows an occupancy sensor to have its total output energy adjusted to conform to the area to be covered. Lowering the total ultrasonic energy in the monitored space lowers the sensitivity of the receiver to inappropriate activations. Lowering the input power to the transmitter also lowers the total internal system noise and provides an improved signal to noise ratio in the receiver. Alternatively, the power applied to the receiver may also be controlled by an adjustable voltage regulator under control of the microcontroller to improve receiver efficiency.