Electrochemistry

Modular, open-source hardware and software for education and environmental monitoring.

 

The original WheeStat may look like a VHS tape box with a couple of wires stuck in it, but it is really a computer driven scientific instrument.  The WheeStat is a three electrode potentiostat, an instrument that measures electric current exchanged between electrodes and chemicals in solution.  

It was designed for teaching electrochemistry and quantitative analysis.  It supports a variety of experiments including cyclic voltammetry and annodic stripping voltammetry.

 
What's it do?

The WheeStat is capable of measuring concentrations of trace metal ions in water, including lead, arsenic and mercury.

For more information, visit the WheeStat user's manual at the link below 

Supported Experiments:

Cycic Voltammetry (CV)

Linear Sweep Voltammetry

Differential Pulse Voltammetry (DPV)

Annodic and Cathodic Stripping Voltammetry

Chronoamperommetry (one and two step)

Repetative CV and DPV expeiments

Cyclic Square Wave Voltammetry

 

Software.

 

The microcontroller that drives the WheeStat comes loaded with software written in the "Arduino-like" program, Energia.  

The WheeStat comes with our Graphic User Interface loaded on a USB flash drive. The GUI comes as an executable program for Windows 32 and 64 bit computers as well as source code written in the program Processing.  At this point, we do not have the GUI application for Mac.  We believe that the Mac App for OSX can be generated relatively easily (see this video).  All experimental parameters are adjusted from your computer using our GUI.  Data are displayed in real time on the GUI chart.  Sequential experiments can be overlayed on the GUI chart.  Once collected, data can be saved as CSV files and opened in excell (or another spreadsheet program).  

All software is open source.  Future updates can be downloaded for free from our GitHub site.

 

Hacking the WheeStat.

 

Want additional functionallity?  Have some unique experiment that you want to run?  No problem.  The programming languages are simple to learn and you will have the source code.  Even if you turn your instrument into a brick, it can be brought back to life by reinstalling the original code.   If you fry the electronics, the odds are that you can fix it by buying a $13 piece of hardware from your choice of electronics vendors (Texas Instruments, Mouser or Digikey)

Electrodes.

The WheeStat comes with two graphite stick electrodes and a simple Ag/AgCl reference electrode.  

 

KITS.

 

Kits are now available.  Kit assembly is described here for the 5 series and here for the 7 series.  They contain everything needed to put together a fully fuctional potentiostat.  Let us know if you need materials to make a set of cheap electrodes. Instructions for asssembling a working reference electrode are here and here.    All surface mount components come soldered in place.  Minimal soldering required:  wires to clips, wires to circuit board, headers to circuit board.  That is it.  Twenty six joints total.

Current code is provided on a usb flash drive. 

This is a new look for the WheeStat.  In addition to the original VHS tape box housing, we now offer the WheeStat fully assembled in a more professional appearing format.  

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WHAT'S UP?

CURRENT PROJECTs

 

August 2020:

  Work during summer 2020 focused on the WheeTrometer spectrometer and on the WheeStat potentiostat.

  The spectrometer is coming along.  We are currently working to improve the intensity resolution by adopting a high resolution analog to digital converter.

  Our work on the WheeStat is focused mostly on increasing the current output available.  In addition, we hope to increase the range of frequencies that can be obtained by adding a digital to analog converter.

August, 2017:

   Work during summer 2017 focused on two projects, the WheeStat potentiostat and the stopped flow spectrometry apparatus.

  •    Work on the WheeStat included changes to the user interface, firmware and hardware.  The newest version of the user interface, WheeStat6.0c, has a new zoom feature and a few bugs from the older interface have been fixed.  We believe the new hardware will be out by the end of 2017.  The new hardware will have an improved method for turning off applied voltatage between experiments.  This is a hardware fix that requires modification of the firmware as well.  We will offer an add-on for our earlier hardware versions that incorporates this feature.  Addditional changes include increased current ranges and the potential for significantly increased scan rates.

  • Work on the stopped flow spectrometry project focused on increasing the injection speed.  Our initial effort focused on developing a rack and pinnion drive for the syringes.  This improved injection speed relative to the lead screw drive but failed to meet target speeds due, we believe, to limited torque provided by the small NEMA 17 motors we chose.  Our next attempt employed larger NEMA 23 motors.  These have significantly higher torque.  Unfortunately, our flow cell was unable to contain the generated pressure and began leaking.  Current efforts are focused on developing a lab-built UV-vis cell that will hold higher pressures.

 

September, 2016:

  • Our work to automate solid phase synthesis of peptides / DNA, etc has progressed well, although the chemistry is more involved that I had origianally thought.  We have made our first attempt at synthesis of a cystiene modified tri-peptide

  • Our application for recognition by the IRS as tax exempt under 501(c)3 has been approved.

  • We have begun work on a low cost visible spectrometer that will use home built reflective optics.

  • We are working on developing a stopped flow kinetics instrument based on commercially avialable spectrometer.  Our current prototype is able to acquire spectra within 120 ms of mixing.  This dead time appears to be limited by the power of the motors we used.  We are investigating the use of larger motors and hope to get the dead time down to below 12 ms.

 

EVENTs

6-10

PITTCON CONFERENCE & EXPO 2016

 

Presentation  in Atlanta, GA,  March 6-10, 2016

Our talk was well recieved at the Educational symposium at PittCon

CONTACT

4989 Tilley Creek Road

Cullowhee, NC 28723

Tel: 828-293-7781
 

 

Mail:  summers@wcu.edu

j6summers@gmail.com

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21

2016 SE REGIONAL ACS MEETING

Oct 23-27, SouthEast Regional Meeting of the American Chemical Society, Columbia SC

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