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Team:UC Davis/Potentiostat Design
From 2014.igem.org
A potentiostat is an instrument capable of maintaining a voltage bias between electrodes. The bias encourages diffusion but more importantly the transfer of electrons which are recorded, and ultimately related to the species present in solution. When faced with the decision to buy or build our potentiostat, we found that the available solutions did not fit our needs. We decided to create our own. We developed an abstract and found a microcontroller with a 16-bit ADC (13 bit ENOB). We then designed, modeled, built and tested our potentiostat under a range of conditions. We went on to create a catalog of prototypes. The final product is the OliView potentiostat: The first arduino-compatible potentiostat to incorporate a 16-bit ADC.
Hardware
The CheapStat is a budget friendly device developed at UC Santa Barbara several years ago. We aspired to build this circuit and modify the software for our purposes, however, the microcontroller on the CheapStat was controlled predominantly in machine level code. The learning curve seemed unreasonable considering our deadline, so we had to find another solution.
We were forced to build our own. With a clean slate, we wanted to create a device that would fulfill our needs, but also be welcomed by the iGEM community. We aimed to match the performance of the CheapStat, but also improve in three ways: increase the effective range of the instrument, decrease the cost of the circuit, and convert to an arduino-friendly microcontroller. In this capacity, we have succeeded.
We modeled our circuit after the CheapStat, eventually including more than 30 components. We went on to create five iterative prototypes. The schematic and board files for the various prototypes are all available here.
To read more about the OliView hardware, click here.
Software
The OliView software was written in C++ within the Qt Creator IDE. The backend of the software includes the GNU-licensed library QCustomPlot for graphing, and the open-source biquad library by Nigel Redmon, for digital signal processing. These elements have been incorporated with more than 1,200 lines of UC Davis code to create a feature-rich environment for controlling the OliView potentiostat. Our progress was updated through the UCDiGEM OliView Github . We included features for statistical analysis as well a .CSV exporting feature
The downloads section includes all the files necessary to build and run the OliView system. Schematic and board files for the OliView potentiostat are provided in Eagle V6.6 format. CAM processing files have been optimized for production by Seeed Studios, Inc.
To read more about the OliView software, click here.
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