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 electroanalytical 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 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 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 ◦ ◦ ◦ ◦ Square Wave Linear Sweep Stripping Cyclic Voltammetry Front Panel PCB Assembly Joystick To Cell Electrodes Design and implement a three electrode potentiostat, based on the Cheapstat Easier to use interfaces GUI on a PC No joystick Ease of assembly and use by students, faculty, and staff Three electrode design 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 120VAC 60Hz 15A USB Processor Voltage Converter Device Under Test (DUT) Processor ◦ Firmware Display/Data Management System (DDMS) ◦ GUI software Power supply Data/Display Management System 120VAC 60Hz 15A USB Processor 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 120VAC 60Hz 15A USB Processor Voltage Converter Device Under Test (DUT) Pre- test Mode Test Mode Calibrate instrument Configure processor for the test to be executed Execute test script that was entered during Pre-Test Display results during test Post Processing ◦ Report generation Data/Display Management System 120VAC 60Hz 15A USB Processor 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 Research ongoing regarding firmware development environment CheapStat Parts have been ordered Software development kit to preserve schedule Test existing Ardustat Need DUT – Chlorine Generator?