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Team:UC Davis/Potentiostat Design Inspiration Iteration
From 2014.igem.org
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| - | <img src="https://static.igem.org/mediawiki/2014/5/53/UCDavis_Cheapstat.png"/ | + | <img src="https://static.igem.org/mediawiki/2014/5/53/UCDavis_Cheapstat.png" width="400px;'/>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.<br><br>We were ultimately 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.<br><br> We modeled the potentiostat circuit in TINAspice to better understand the limitations of our opAmp selection. We also designed an abstract to better visualize our circuit design.<br> |
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Revision as of 06:56, 15 October 2014
Inspiration & Iteration
Inspiration & Iteration
Software
Software & Downloads
Get Started!
Getting Started
Inspiration and Iteration
Breadboard
Development began on the protoboard. Circuit designs were prepared using the CheapStat as a reference. SMD-ICs were soldered to DIP adapters and the potentiostat was wired for the first time. The protoboard became the primary device with which to develop the software. The protoboard was not designed with a switch to control current ranges, it did include noise however. 
Fast Fourier transform of the recorded signal showed that the largest component was from the 60 Hz range. Extensive testing showed that the noise was related to the protoboard itself as the signal persisted long after the components were removed. There was no other option but to continue the development by creating a circuit board.
Version 1.0
Our first circuit board was designed and drawn entirely by hand. The traces and pads were created as an SVG file. After several file type exchanges, the file became a DXF and was loaded into software for precision CNC milling. The board was milled using the LPKF Circuit Pro milling machine in the TEAM prototyping lab on campus. The board was populated and tested using the traditional potentiostat test: reference and counter shorted, resistor connecting working electrode lead and ref/counter lead.
The circuit contains a switch to short the reference and counter for easy testing or use as a two electrode potentiostat. For now the switch is adjusted in the Teensy software.
Version 1.1
Our biosensor required a potentiostat. 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. We were faced with the decision to buy or build.
Unfortunately, there weren't any entry-level potentiostats that met our requirements, and commcercial potentiostats are in the thousands of dollars. We needed a cheaper solution if we wanted our device to be consumer friendly. We researched the literature for potentiostat circuits and were presented with the CheapStat.
Version 1.2
Our biosensor required a potentiostat. 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. We were faced with the decision to buy or build.
Unfortunately, there weren't any entry-level potentiostats that met our requirements, and commcercial potentiostats are in the thousands of dollars. We needed a cheaper solution if we wanted our device to be consumer friendly. We researched the literature for potentiostat circuits and were presented with the CheapStat.
Version 1.3
Our biosensor required a potentiostat. 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. We were faced with the decision to buy or build.
Unfortunately, there weren't any entry-level potentiostats that met our requirements, and commcercial potentiostats are in the thousands of dollars. We needed a cheaper solution if we wanted our device to be consumer friendly. We researched the literature for potentiostat circuits and were presented with the CheapStat.
Version 1.4
Our biosensor required a potentiostat. 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. We were faced with the decision to buy or build.
Unfortunately, there weren't any entry-level potentiostats that met our requirements, and commcercial potentiostats are in the thousands of dollars. We needed a cheaper solution if we wanted our device to be consumer friendly. We researched the literature for potentiostat circuits and were presented with the CheapStat.
Version 2.0
Our biosensor required a potentiostat. 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. We were faced with the decision to buy or build.
Unfortunately, there weren't any entry-level potentiostats that met our requirements, and commcercial potentiostats are in the thousands of dollars. We needed a cheaper solution if we wanted our device to be consumer friendly. We researched the literature for potentiostat circuits and were presented with the CheapStat.
