# Arduino-based Potentiostat for Cyclic Voltammetry

Hello,

I've been using this paper to build an arduino-based potentiostat.
Development_of_a_low-cost_Arduino-based_potentiostat.pdf (850.7 KB)
I've made all the connections as shown in the circuit schematic but I can't figure out how the batteries are connected. All the connections to to pin 2,3 and 6 of the op-amps but are any additional connections to op-amps I need to make that are not shown on the schematic?

Here's what my circuit looks like.

Looking at the code, I was wondering how steptime was being calculated in milliseconds in Fig 7 of the paper. For polarization experiments, step size is always increased in the units of mV/s but I am stumped.

I've never really used arduino before I would really appreciate it if somebody helped me understand this. Thank you

I wonder too - the findAverage function isn't doing what I'd expect, its not doing the mean over the step. It has a fixed step time.

The cyclic stuff is in figure 5, not figure 7. That decides the voltage change per step.

It could be increasing the voltage by a fixed magnitude and the steptime is being used to control the rate of voltage change.
Ideally I wanted to use 1mV/s as my step size but arduino's resolution is 4.8mV so I want to do 4.8mV/s.

No, the stepsize is constant, and the voltage change is constant - the code given uses a constant dV/dt rate. You'd have to rework the code for varying rates.

Okay, I'll try to run what I have right now because I don't need varying rates. I just need to understand how to change the values in the code.

Also, I made some new connections to the circuit. I connected pin 4 and pin 7 of all op- amps to +9V and -9V respectively. Is there anything else I need to do? Here's a picture of what I have.

Hard to tell from the photo but it looks like a circuit(!) I'd carefully check all the connections off against the diagram before powering up the first time - especially that power and ground rails are going to everything they should. opamps are robust devices in practice so long as they all have they power rails connected.

Hi,

I think you need to sit down with pen(cil) and paper and draw a circuit diagram.
Include pin names and component labels to identify circuit items.

Thanks.. Tom...

hello,

the blue negative rails are GND
bottom '+ve rail' is Vcc- connecting to pin 4 of all op amps.
the top '+ve rail' is Vcc+ connecting to pin 7 of all op amps.

I did make a rough circuit diagram with pin numbers for op amps to help with the connections.
Can you confirm how the legs of potentiometers are connected here?

Thank you

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