An Optical Sensor for Measuring In-Plane Linear and Rotational Displacement

Area of Science:

• Optoelectronics
• Sensor Technology
• Biomedical Engineering

Background:

• Accurate measurement of in-plane displacements is crucial for monitoring device performance and patient conditions.
• Existing methods may lack the precision or applicability for dynamic, real-world scenarios in wearables.

Purpose of the Study:

• To develop and validate an optoelectronic sensor for quantifying linear and rotational displacements between parallel surfaces.
• To assess the sensor's accuracy using different color gradient wheels and its potential in wearable applications.

Main Methods:

• Utilized a photo detector to measure reflected Red, Green, Blue, and Clear light intensities from a color gradient wheel.
• Employed a polynomial regression algorithm trained and validated with data from a custom positioning stage.
• Evaluated sensor reliability with wheels featuring changing hue and hue-and-saturation.

Main Results:

• Achieved high predictive accuracy for linear and rotational motion detection.
• Coefficients of determination (R^2) exceeded 0.94 for hue-only and 0.92 for hue-and-saturation wheels.
• Demonstrated sensor's capability to quantify displacements under varying color conditions.

Conclusions:

• The developed optoelectronic sensor accurately quantifies in-plane displacements and rotation.
• Potential applications include detecting slippage in footwear, orthotics, and prosthetics.
• This technology can aid in managing clinical conditions affecting gait and foot health.