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

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

A 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.

A previous potentiostat was attempted by a project team using an open source design, the Ardustat Hardware used was an Arduino processor board, with a prototype “daughter board” 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 had no documentation or comments for either the firmware or the application software The team was unable to meet the project goals

Before BenAfter Ben

 An MEng student has implemented the hardware using a PCB assembly, and verified the design’s functionality  The existing code has been reverse engineered and documented/commented  However, the Ardustat is a two electrode configuration, and the GUI is very limited in its capabilities

 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

 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 ◦ Square Wave ◦ Linear Sweep ◦ Stripping ◦ Cyclic Voltammetry

Front PanelPCB Assembly Joystick To Cell Electrodes

Design and implement a three electrode potentiostat, based on the Cheapstat Three electrode design Streamline user 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

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

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

 Processor ◦ Firmware  Display/Data Management System (DDMS) ◦ GUI software  Power supply

 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

 Pre- test Mode  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

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

Parts are In Missing Programmer and 165KOhm Resistor Parts ordered today via Tom PCB Layout has been delivered to Doug Jackson Status Update from Doug Jackson today

 Full Software overview from Ben Williams received.  Williams final report documentation has been fully examined.  GUI Requirements defined ◦ Less Clutter ◦ Intuitive Process ◦ Remove inoperable options.  Investigation of Processor Requirements

 Cyclic Voltammetry Test will be used on both the Ardustat and Cheapstat for comparison of two electrode versus three electrode configurations.  Sample test will be a measurement of ascorbic acid (Vitamin C) in orange juice.  Resulting graphs will be compared with Potentiostat article.