@rcbb

Hi, @Will-Dickson,

I've been running some experiments with the Potentiostat, but I'm getting a lot of noise. At first I thought it was the power source, but I've changed it and still get noisy measurements.
Noise

I'm running cyclic test, from 0.5 to 1.2, with volt/sec in 0.05.
Any idea?

rcbb

@mbeneck

You need to put a shim/spacer in there for good contact. Sometimes the SPEs come with it, otherwise you can just cut a little bit of card stock.

I had this same question. Would like to use for just measuring potentials, like ORP, pH, ISE, etc. From my research, if you take the counter electrode out of the circuit, you can make this measurement. I haven't got one to try this on yet. Suggest you research "open circuit potential" on web. Seems to be similar question on other potentiostats.

I think Excel will let you do this. Just plot one of the graphs with its time axis; then add the second graph, with its time axis. Excel will locate the points properly. If you want to get fancy, you could write code in Python, or any other scientific programming language, that interpolates between time points and give you estimated graph points from one graph at the other graph's time points.

LarryD

I'm attempting to implement something similar to perform AC voltammetry at higher sample rates and frequency but am struggling with my understanding of Arduino code. Where exactly in serviceDataBuffer (in ps_system_state.cpp) does the If statement go?
I've tried inserting if (run_complete) into a few places that seeem logical to me but either it has no effect or everything breaks.

Could anyone enlighten me as to how to implement these changes in greater details?

Hi Will,

Thanks for your feeback. You're right about my system specific differences, even for param dt =0.05 I get a median of 0.058.

I've attempted to implent the firmware changes outlined as I only need a sample rate of 115Hz however I haven't noticed any difference. I'm not very familar with arduino programming and I suspect I haven't implmented the changes in ps_system_state.cpp correctly. I've attached my changes in hopes that you might notice some sort of obvious error.

Regards

Blair

void SystemState::serviceDataBuffer() { // Check for last sample flag to see if done bool run_complete = false; if (lastSampleFlag_) { if ((run_complete = true)); } // Empty data buffer size_t buffer_size; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { buffer_size = dataBuffer_.size(); } while (buffer_size > 0) { Sample sample; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { sample = dataBuffer_.front(); dataBuffer_.pop_front(); buffer_size = dataBuffer_.size(); } messageSender_.sendSample(sample); } // Send indication that the run is complete if (run_complete) { messageSender_.sendSampleEnd(); lastSampleFlag_ = false; } }

Hi thank you, your thread is very helpful for beginners

Hi, I wanted to know if you had other international shipping options

From my comprehension of chronoamperometry, the applied voltage is regarding the reference terminal which bodes well that the affidavit ought to happen fundamentally on the working anode, while the counter cathode serves to finish the circuit. In any case, I might want to realize is it conceivable to accomplish an in any event, covering on the counter anode simply like how it is on the functioning terminal? All runs I had so far shows rather lopsided coatings that increments with applied voltage.

https://www.7pcb.com/

The Rodeostat FeatherWing does use slightly lower cost components than the Rodoestat in order to keep costs down. However, overall the accuracy of the Rodeostat FeatherWing is fairly comparable to the Rodeostat. The main differences are as follows.

The Rodeostat FeatherWing has a more limited fixed voltage output range (+/- 1.65V) whereas the Rodeostat has a four voltage ranges which can selected via software(+/- 1, 2, 5, 10V).

The Rodeostat FeatherWing comes in a single fixed current range, which is specified at time of purchase, whereas the current range for the Rodeostat can be selected via software (+/- 1, 10, 100, 1000) .

Finally, the Rodeostat is a complete USB instrument which comes preprogrammed with firmware and can be controlled from the host PC using our python library or with Webapp software. In contrast the Rodeostat FeatherWing is designed to be used as an expansion board and only works when connected to a Feather development board, such as Adafruit's Feather M4 Express, PyBadge or PyGamer. You need to write your own firmware for controlling the Rodestat FeatherWing on the Feather development board.

@Babak

With the default hardware and hardware there are four current ranges +/- 1, 10, 100 and 1000 uA. So +/-1000uA is the maximum allowed current range. It is possible to change this but it requires a hardware modification and firmware modification. You won't be able to set higher than 1000uA without these changes. You would need to make these modifications yourself. There are some forum notes on increasing the current range here http://forum.iorodeo.com/topic/67/increasing-current-ranges-to-detect-ma The firmware modifications can be enabled by uncommenting the the #define CURRENT_VARIANT_MILL_AMP and commenting the #define CURRENT_VARIANT_MICRO_AMP in the ps_hardware_variant_defs.h file https://github.com/iorodeo/potentiostat/blob/master/firmware/libraries/potentiostat/ps_hardware_variant_defs.h You then need to reflash the firmware.

@Babak

It is not possible to run multiple experiments, such as constant and cyclic voltammetry, simultaneously with the multiplexed version of the Rodeostat. You can use up to 7 working electrodes, but you still only have 1 reference and 1 counter electrode. So the time course of the potential between the all of the working electrodes and the reference electrode will be the same during a test.