Date of Award
Level of Access Assigned by Author
Master of Science (MS)
Second Committee Member
Third Committee Member
Plethysmography refers to the dynamic measurement of biological tissue volumes that, for example, may change due to fluctuations in blood volume. Photoplethysmography (PPG) makes use of the attenuation of light penetrating into vascular tissues to determine these changes in blood volume. Modern PPG is an optical technique involving low cost photosensors and light emitting diodes (LED), and is capable of measuring multiple biological vitals simultaneously. For example, in addition to heart rate determination, PPG devices can be used as pulse oximeters, capable of calculating the blood oxygen saturation (SpO2) through a series of simple optical calculations performed on either reflectance or transmittance data. In this project, a reflectance-based PPG pulse oximeter was designed to collect blood volume measurements on the foot of a patient. This project also involves using the PPG sensor to determine the effect of vibrational signal on vasoconstriction in the tissue, to provide more information on biological properties, including diabetic nerve damage. The device is constructed via dual wavelength light sources and a phototransistor where the light sources are determined based on the isosbestic point, for oxygenated and deoxygenated hemoglobin.
Mazjanis, Madeline, "Development, Design, and Utilization of a Reflective Based Photoplethysmography Sensor" (2020). Electronic Theses and Dissertations. 3369.