College - Author 1
College of Engineering
Department - Author 1
Electrical Engineering Department
Degree Name - Author 1
BS in Electrical Engineering
College - Author 2
College of Engineering
Department - Author 2
Electrical Engineering Department
Degree - Author 2
BS in Electrical Engineering
College - Author 3
College of Engineering
Department - Author 3
Electrical Engineering Department
Degree - Author 3
BS in Electrical Engineering
Date
6-2026
Primary Advisor
Souvik Kundu, College of Engineering, Electrical Engineering Department
Abstract/Summary
This project developed and evaluated an optical sensing system for detecting changes associated with glucose concentration. The system combined a laser-diode, cuvette sample holder, photodiode, resistive-feedback transimpedance amplifier, high-resolution analog-to-digital converter, and microcontroller. Parametric testing evaluated the effects of input current and feedback resistance on transimpedance gain, output range, and linearity. Firmware was developed to configure the ADC, average repeated conversions, monitor measurement variation, convert raw digital counts into voltage using a source-meter calibration equation, and compare sample measurements with a water reference. A cuvette enclosure maintained alignment between the laser-diode, sample, and photodiode while reducing external optical interference. Testing produced repeatable ADC measurements and measurable changes in the end-to-end optical response. The results demonstrated that stable electrical connections, consistent cuvette positioning, and accurate characterization of the amplifier output range were necessary for reliable calibration and measurement.
URL: https://digitalcommons.calpoly.edu/eesp/724
Included in
Biomedical Commons, Biomedical Devices and Instrumentation Commons, Electrical and Electronics Commons, VLSI and Circuits, Embedded and Hardware Systems Commons