1. Team Members: Kyle Bloomer Josh Geiman Lucas Bennett
Potentiostat
Team Members:
Kyle Bloomer
Josh Geiman
Lucas Bennett
Team Sponsor:
Dr. Cindy Harnett
Team Mentor:
Dr. Andy Dozier

2. Harnett Lab
Dr. Harnett's laboratory needs 15 potentiostats for her microfluidics lab
Off the shelf potentiostats range in price from $5K to $10K, which is prohibitive for an instructional lab
Commercial Potentiostat

3. What is a Potentiostat?
A Potentiostat is an instrument that is used to characterize electrochemical reactions
Fuel cells – reacts liquid fuel and oxidizer to produce electricity
Gas generators – Uses electrolysis to generate gas
A potentiostat measures the voltage difference between a Working Electrode and a Reference Electrode
Three electrode configuration
Most commercial potentiostats provide a second mode of operation that measures the current flow between the Working and Counter Electrodes
This mode is known as a “galvanostat”

4. History - Ardustat
A previous potentiostat was attempted by a project team using an open source design, the Ardustat
The Ardustat was a two electrode configuration
Ardustat electrical design was poorly documented, which caused the project team to have difficulty implementing it for the project
Software design was “spaghetti code”, and it had no documentation or comments for either the firmware or the application software
Hardware used was an Arduino processor board, with a prototype “daughter board”
The team was unable to meet the project goals

5. Ardustat Hardware

6. Ardustat GUI – Connect & Setup

7. Ardustat GUI – Data Logging

8. Ardustat Code Example Show pictures of GUI or firmware code Before Ben
After Ben

9. Previous Project Diagram

10. Previous Project Test Set

11. Current Status
An MEng student has implemented the hardware using a PCB assembly, and gotten it to work
The existing code has been reverse engineered and documented/commented
BUT the Ardustat is a two electrode configuration, and the software GUI is very limited in its capabilities

12. Research
We have found an open source, three electrode potentiostat, known as the “Cheapstat”
Cheapstat was developed by UC Santa Barbara to provide an affordable alternative to COTS potentiostats

13. Cheapstat Features
Input parameters must be set through an onboard LCD and 5-way joystick
The display is very limited
LCD on the Cheapstat processor “box”
Provides multiple measurement modes
List the modes here

14. Cheapstat Hardware Front Panel PCB Assembly JoyStick To Cell
Electrodes

15. Design Goals - Hardware
Design and implement a three electrode potentiostat, based on the Cheapstat
Three electrode design
Easier to use interfaces
GUI on a PC
No joystick
Ease of assembly and use by students, faculty, and staff
PCB assembly techniques
USB processor to PC interface
External power sources
Full documentation of hardware
Schematics
Simulation results
Assembly diagrams
List of Materials

16. Design Goals - Software
Develop GUI and firmware using modern software engineering techniques
No spaghetti code
Comment all code
Provide a software library
Document all the application software and firmware
Installation notes
User’s Manual

17. Project Goals - Other
Characterize electrical performance for a typical electrochemical device
Compare electrical measurements with the existing Ardustat
Two electrode vs. three electrode measurement differences

18. System Diagram

19. Major Components Processor Display/Data Management System (DDMS)
Firmware
Display/Data Management System (DDMS)
GUI software
Power supply

20. System Diagram

21. Processor Requirements
Capture the test configuration
Measurements to be made, ranges, etc.
Execute the test using the measurements that have been established by the operator
Log and time stamp test results in NVRAM
Send measurement data to Display/Data Management System (DDMS) during test
When polled by the DDMS, send the test results in CSV format to a file on the PC

22. System Diagram

23. DDMS Requirements Pre- test Mode Test Mode Post Processing
Calibrate instrument
Configure processor for the test to be executed
Test Mode
Execute test script that was entered during Pre-Test
Display results during test
Post Processing
Report generation

24. GUI Mockup

25. System Diagram

26. Voltage Converter Three options are available:
Wall Wart
USB
Battery power
Microprocessor requires 5 VDC
Estimated 3 watts

27. Current Status Build and test Cheapstat using current design
CheapStat Parts have been ordered
Research ongoing regarding firmware development environment
Software development kit to preserve schedule
Test existing Ardustat
Need DUT – Chlorine Generator?

28. Questions?