Wireless Sensor Oscillating Wave Impedance Measurement
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Solution Overview
Problem
Conventional wireless remote sensors face challenges in detecting small variations in impedance due to masking by changes in coupling and manufacturing tolerances, making it difficult to accurately determine sensed parameters.
Innovation Solution
The implementation of a wireless remote sensor system that produces an oscillating wave based on sensed parameters, using a charge/discharge circuit with variable impedance elements and adaptive triggers to normalize charging time, and incorporates a Wheatstone bridge arrangement with internal resonant circuits to amplify small changes, along with optical feedback schemes to isolate sensor values from coupling variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional wireless remote sensors use simple RLC circuits to communicate sensor values via reflected impedance, then the device complexity is low, but the measurement precision deteriorates because small impedance variations are difficult to detect and masked by coupling changes and manufacturing tolerances
Solution Approach 1:
The patent transforms the static RLC circuit into a dynamic oscillating system. The sensor circuit is configured to generate oscillating waves at a specific frequency, and the oscillation characteristics (frequency, amplitude, duty cycle) are modulated by the sensor impedance variations. This dynamic approach converts small impedance changes into detectable oscillation parameter changes, resolving the measurement precision problem while maintaining reasonable circuit complexity.
Solution Approach 2:
The patent employs periodic oscillating waves generated by the sensor circuit to communicate sensor values. The oscillation period and duty cycle are deliberately designed to encode impedance information. By using periodic action instead of continuous DC impedance coupling, the system achieves better measurement precision through time-domain modulation, making small variations detectable against the periodic signal background.
2Reliability
If wireless remote sensors rely on reflected impedance to communicate sensor values, then the ease of operation is high, but the reliability deteriorates due to masking by coupling variations and manufacturing tolerances
Solution Approach 1:
The patent implements a feedback mechanism where the sensor circuit receives power from the transmitter, generates oscillating waves based on its impedance characteristics, and the transmitter detects these oscillations to determine sensor values. The system continuously monitors oscillation parameters and adjusts accordingly, creating a closed-loop feedback system that improves reliability by compensating for coupling variations and manufacturing tolerances through active signal processing.
Solution Approach 2:
The patent introduces oscillating wave generation as an intermediary mechanism between the sensor impedance and the transmitter detection. Instead of directly transmitting impedance information through reflected impedance, the sensor circuit first converts impedance variations into oscillation parameter variations, which then serve as the communication medium. This intermediary transformation enhances reliability by making the signal more robust against coupling and manufacturing variations.
3Difficulty of detecting and measuring
If the sensor circuit uses variable impedance elements to represent sensed parameters, then the adaptability is high, but the difficulty of detecting and measuring worsens because small variations are masked by coupling and tolerance variations
Solution Approach 1:
The patent applies the concept of vibration to electrical circuits by generating electromagnetic oscillations. The sensor circuit produces oscillating waves whose characteristics are modulated by the variable impedance elements representing sensed parameters. This vibration-based approach amplifies small impedance variations into detectable oscillation changes, reducing the difficulty of detection while preserving the ability to measure various sensor parameters through impedance modulation.
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 allows for accurate and reliable wireless determination of sensed values by enhancing measurement resolution and minimizing interference from coupling and manufacturing variations, enabling precise communication of parameter changes.
Implementation Method 1
Wireless remote sensors are typically powered by and communicate with an inductive transceiver. This means that the power used to operate the sensor can be provided to the wireless remote sensor without the need for wires or other direct electrical contact.
Implementation Method 2
Many conventional wireless remote sensors incorporate a sensor having a capacitance or resistance that varies as a function of the parameter to be measured. The RLC circuit is inductively coupled to the inductive transmitter so that the RLC circuit affects a characteristic of power in the inductive transmitter via reflected impedance.
Implementation Method 3
The oscillating wave is roughly a square wave produced by a charge/discharge circuit, with the low portion of the square wave corresponding with the charge time and the high portion corresponding with the discharge time.
Data Source
AI summary
A wireless remote sensor (110) that is powered by an inductive transmitter (112) and is configured to produce an oscillating wave that varies based on one or more sensed parameters. The oscillating wave is communicated to the inductive transmitter (112) by reflected impedance, where it can be detected to determine the sensed value(s). In another aspect, the present invention provides a wireless remote sensor with a Wheatstone bridge arrangement having an internal resonant circuit to produce an electromagnetic field indicative of the sensed value. In a third aspect, the present invention provides a wireless remote sensor with optical feedback from a reference circuit and a sensor circuit. In a fourth aspect, the present invention provides a wireless remote temperature sensor having coils printed on a material with a high coefficient of thermal expansion so that the size and/or shape of the coils varies as the temperature increases or decreases.