I can not connected to nanostat.

[flukesuntisak]

Dear Prof. Burke, @PeterJBurke

I have already compiled and transferred the firmware to the board. The board shows wifi "nanostatAP".

Now I am stuck on how to control the board using the web . I can not open ip address 192.168.4.1 and nanostat.local either.

Do you have any suggestion?

Regards, Suntisak

[PeterJBurke]

I fixed the readme. Basically when in AP mode you have to go to 192.168.4.1 then you get the webpage to enter your wifi SSID and pwd. Reboot, then you can go to ether nanostat.local when connected to your local network, or the IP address assigned by your local router.

[flukesuntisak]

I am already connected to the AP, but I don't know why I am not able to access 192.168.4.1 on both my smartphone and PC.

If not too much, could you please provide me a bit of help?

to make sure I am doing it the correct way.

After downloading the file from GitHub, I can then transfer the firmware by opening this download folder using PlatformIO.  first clicking the build button to compile it. Then, click the upload button.

Am I doing it correctly?

note: i fabricaates nanostat Version3dot5dot1.

[PeterJBurke]

OK. I put a "troubleshooting access point" in the readme. Please use it to confirm you have an IP address on your PC.

It sounds like you uploaded the firmware correctly, but you did not upload the website files (html files). You need to upload all of the html and other files from the "data" directory in the repo. I put a link to some youtube tutorials about how to do this in the readme. From the new readme:

You also need to transfer the website files in the data directory of this repo. This includes all the html files and js (javascript) files that serve up the website. ESP32 has a disk structure called "SPIFFS". For some tutorials on this see: https://www.youtube.com/watch?v=Pxpg9eZLoBI and https://www.youtube.com/watch?v=NVD46mRbVXM

[flukesuntisak]

Very appreciate! I will try to do it as you recommend.

[flukesuntisak]

It does work now. Thank you !

However, I obtained the CV signal of Fe(CN)6 as shown below. Do I have to configure something?

[flukesuntisak]

this is IV curve, obtained by connecting to dummy cell

[PeterJBurke]

I would recommend to test the nanostat on a resistor to confirm it is working and calibrated correctly. Also make sure to run the calibration routine. Instructions on the "Cal" part.

The resistance value 10 kohm to 100 kohm is probably a good test. It depends on your cell.

What is your dummy cell? If you give details it would help troubleshoot.

Once that is set up, then it is beyond the scope of this github account, but you need to get your electrochemical cell working properly. I don't know the details, if you post them I can help troubleshoot, but it is difficult to remotely troubleshoot the details of the cell.

The peak currents you expect for your experiment depend on the concentration and electrode area. You can look at our paper for the exact values we used, and the model number for the electrodes.

In addition, here is a good reference paper for theory and operation is:

Elgrishi, N., Rountree, K. J., McCarthy, B. D., Rountree, E. S., Eisenhart, T. T., & Dempsey, J. L. (2018). A Practical Beginner’s Guide to Cyclic Voltammetry. Journal of Chemical Education, 95(2), 197–206. https://doi.org/10.1021/acs.jchemed.7b00361

It looks like you might have a dirty working electrode, and possibly your reference electrode is dry. We had that problem and then we switched to a gold working electrode (instead of glassy carbon), which is much easier to keep clean.

Also, our Ag/AgCl reference electrode was dry and old, we had to replace it with a new one. Your second plots seem to show some instability/hysteris which may be caused by a faulty reference electrode.

You might also want to contact Basi or whoever your electrode company is. If using your own home made electrodes, try cleaning them.

[flukesuntisak]

For electrochemical experiments, i used a commercial screen-printed electrode. The CV was performed in 5mM Fe(CN)6 containing 0.1M KCl solution. this is the signals I got. BTW, in setup, i dont know about TIA gain (it was set at 350kohm for this experiment)

[flukesuntisak]

Good news, it is working !, when I set the TIA to 7 kOhm,

and this is 3.5 kOhm

Thank you

[PeterJBurke]

Great! If TIA is too large, the ADC saturates.