The research group at the Food Science Department had been studying high temperature phase transitions in starch polymers using laser light scattering. They had constructed a light bench with source, pinhole, scattering cell, and scattered light detector. However, they needed a detector to quantify the unscattered light. With this they wanted to construct cloud point curves. They had a working prototype for this that was based on a photoresistor, but the signal was not as stable as they would have liked, and it was being output on an analog recorder.
They had a NI Data Acquisition Card and LabView to build a virtual instrument for recording the output. They also wanted us to record the temperature and light emission readings at the same time.
For this purpose we built the LabView virtual instrument which took the readings from a thermocouple and voltage from a photodiode and plotted them on the screen on a graph as well stored the data recorded into a CSV file. This data then could be processed as desired.
A photodiode (S2386 18K)was chosen due to its greater sensitivity and linear response compared to a photoresistor. An op-amp (LF356) was also used to amplify the current from the photodiode. The photodiode was used in the photovoltaic mode. A thermocouple was used to read in the temperature of the cell.
Sponsor Company: PSU Food Science Department
Supervisor: Dr. Greg Ziegler
Faculty Coach: Mr. Chris Rogan
Students:
Duane Cornish
Ang Li
Yash Kadam
