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

 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 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”

      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

 ◦ ◦ Show pictures of GUI or firmware code Before Ben After Ben

   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

  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 ◦ List the modes here

JoyStick

Front Panel PCB Assembly

To Cell Electrodes

      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

   

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

Data/Display Management System

USB Processor 120VAC 60Hz 15A Voltage Converter Device Under Test (DUT)

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

Data/Display Management System

USB Processor 120VAC 60Hz 15A Voltage Converter Device Under Test (DUT)

     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

Data/Display Management System

USB Processor 120VAC 60Hz 15A Voltage Converter Device Under Test (DUT)

    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

Data/Display Management System

USB Processor 120VAC 60Hz 15A Voltage Converter Device Under Test (DUT)

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

    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?