Processor Board

Background Information• Dr. Harnett’s lab needs up to 15

potentiostats that are:• Inexpensive (less than $100 per unit)• Easy to assemble by students

• OTS solutions range from $5K to $10K

Theory of UseA potentiostat is:• The electronic hardware required to

control a three electrode cell and run most electro-analytical experiments

• An electronic instrument that controls the voltage difference between a Working Electrode and a Reference Electrode.

• It measures the current flow between the Working and Counter Electrodes.

Design Methods• Two-Electrode Potentiostat• Previously developed by Capstone

group during Fall 2010• Follow-on project by Ben Williams• Firmware improvements• Hardware component revision

• Three-Electrode Potentiostat• Originally developed by University of

California Santa Barbara

Objectives• Improve existing Two-Electrode Potentiostat• Implement Three-Electrode Potentiostat• Test and compare results between designs

Two and Three Electrode Potentiostats

Sponsored By

Group Members: Kyle Bloomer, Luke Bennett, Josh Geiman

Three-Electrode Design

Cindy Harnett

DDMS

Two-Electrode Design

Arduino Development Board Daughter Card

DDMS

Experiment• Tested the current difference in four orange juice

samples caused by varying amounts of ascorbic acid• 0, 0.1, 0.2, and 0.3M of ascorbic acid in each

sample, respectively• Electrode usage• Counter: Platinum wire• Working: Pencil “lead”• Reference: Standard Ag/AgCl

Expected Results Two-Electrode Results

Three-Electrode Results

Conclusions and RecommendationsResults gathered from experiment do not coincide with expected results.• Possible contributing factors:• Reference electrode in poor condition• Possible firmware issues with measurement

execution• Possible errors in chemistry related procedures