Request for Guidance on ESP32 S2 Microcontroller-Based Electrical Impedance Tomography Device

[popular1119]

Dear RonAaron61,

I hope this message finds you well.

My name is Peng Piao, and I have been deeply inspired by your project on the ESP32 S2 microcontroller-based Electrical Impedance Tomography (EIT) device. I have thoroughly reviewed the materials and documentation you have shared on GitHub and am truly impressed by the innovation and technical expertise demonstrated in your work.

As someone who is passionate about electronics and microcontroller-based projects, I am particularly interested in understanding the thought process and methodology behind your project. While the documentation provides a comprehensive overview of the implementation, I am eager to learn more about the challenges you faced, the decisions you made, and the techniques you employed during the development of this device.

I would be immensely grateful if you could spare some time to share your insights and experiences with me. Specifically, I am interested in discussing:

1. The initial conceptualization and design phase of the project.
2. The selection process for the ESP32 S2 microcontroller and other key components.
3. Any significant challenges or obstacles you encountered and how you overcame them.
4. Best practices and tips for someone looking to embark on a similar project.

I believe that your guidance would be invaluable in helping me gain a deeper understanding of EIT technology and its practical applications. I am eager to learn from your experience and apply this knowledge to my own projects.

Thank you very much for considering my request. I look forward to the possibility of connecting with you and learning from your expertise.

Best regards,

Peng Piao
pengpiao1119@gmail.com

[RonAaron61]

Hello Peng Piao,

I'm happy to have someone interested in my project.

First of all, about the conceptualization of the design, I got the concept because my undergraduate thesis is also about EIT, so I got the abstract design and the main concept of how it works from my lectures and other papers. Then I modified and implemented it on this project.

The reason why I chose the ESP is that it’s relatively cheap and has many pinouts. Because based on my design, it required at least 16 pins for the demultiplexer/multiplexer and another 5 pins for the AD9833 and ADS1115 modules, the integrated wifi module can also be useful if you want to make it wireless. For the other components, I looked for papers related to EIT and analyzed what type of components they used, so that I could use them.

After finding what components are suitable for my project then I can make a prototype of each circuit/component to see if it actually work. Then it can be combined into one functional protoype. At this time is when you need to solve any challenges, especially because when prototyping I used a proto-board and jumper wires, which made it look stressful, that is why I suggested making them one by one. Always double-check for the wire and pin connection, especially if it’s related to supply, the type of the IC may also affect the result. Also sometimes the problem is the one you least expect it.

I think it’s best to look for multiple papers/journals about EIT and see what components they use and try it by yourself, to find which is the most suitable for the project.

I'm welcome for related questions, but I may not be good at explaining, because I’m not really an expert in this field.

I hope this answers most of your questions,

Best,

Aaron

[popular1119]

Hi Aaron,

Thank you very much for your previous response. I have a few more questions that I hope you can help me with:

Firstly, due to the geographical difference between us, there might be a time difference. Therefore, I may not be able to respond to your messages promptly, and I appreciate your understanding.

1. Purpose and Published Articles: Could you please share what your ESP32 S2 Electrical Impedance Tomography (EIT) device is primarily used to measure? Additionally, have you published any articles or papers about this device? If so, I would love to read them.

2. Lung Monitoring: Is your EIT device used for lung respiration monitoring? I have an EIT device here, but it does not work properly when used for lung respiration monitoring. Therefore, I hope to understand some relevant details.

3. Microcontroller and Chip Communication: I would like to learn more about the control and communication between microcontrollers and other chips. Although I use many devices, I do not know much about their internal principles. Do you have any recommended courses or resources that can help me better understand this area?

Thank you very much for your time and assistance. I look forward to your response.

Best regards,
Peng Piao
pengpiao1119@gmail.com

[RonAaron61]

For now, I only use my project device for measuring objects (eq. plastic or metal) on the water solution phantom, like one of the images on the GitHub page. But maybe later I also want to test if it can detect anomalies (eq. cancer) in objects that have the same impedance as the human body, I have tried to make an agar phantom in my previous undergraduate project using the reference from Bennet D. (2010). But I also want to improve my device because I don’t know why, but when I tried to scan an object in the middle of the phantom it doesn’t show great. For now, I haven’t published a paper or articles related to this project.

That is an interesting Idea to use it as a lung monitoring device. But I haven’t tried it to scan on the thorax area. Maybe it is related to the current being injected or the frequency being used? Because from what I know higher freq eq. ≥ 50kHz is more able to penetrate cells (?).

To be honest, I also don’t really know how the principles of the chip work, I only know how to use it and maybe some of the specifications based on its datasheet. If we speak maybe like the modules that I used, I think you can just search online on its pinout, and how to connect and code it to the microcontroller, I think there is a lot of websites or videos explaining it because most of it is open-source. Some of the modules used either I2C or SPI communication protocol, maybe you can look at it while trying the module itself. When I find some interesting modules or IC I usually just search what is the pinouts and how to use them online, and then tried it myself.

Hope this help

Best, Aaron

[popular1119]

Dear Aaron, I hope this email finds you well.

I have been following your ESP32 S2 Electrical Impedance Tomography (EIT) project on GitHub with great interest. Your work is truly inspiring, and I am eager to learn more about the technical aspects of the project. From what I have gathered, you initially developed each module of the project independently before integrating them to complete the final assembly. This approach seems logical and efficient. However, I am a bit confused about one aspect: does successfully developing each module individually guarantee that the final integration will be successful? Are there any specific challenges or considerations that arise during the integration phase that one should be aware of?

Thank you very much for your time and assistance. I look forward to your response.

Best regards, Peng Piao

[RonAaron61]

Hi Peng Piao,

I would say that it's not 100% guaranted, but building it one module at a time then gradually start adding another components while check if it still working can minimize the error, whilst if you doing it all at once, it would be difficult to identify which one is the problem, because you have to prob each pins to analyze it.

During the integration process because I usually use a project board with lots of jumper cables, maybe you can try simplify the cable connections so it doesn't get confusing or label the important cables like the output / input, because let say you have a break from the project for a couple of day, you would still know which cables is which. Also check the component specifications, because it is possible that the output of that component exceeds the input specifications of the next connected component, especially when dealing with gain. but I think because all components are connected to the same supply voltage, the possibility of this is low.

One of the most important things is to check what kind of output or input the component requires.

Then you also need to be careful when combining the coding of several modules into one final program.

Hope this help Best, Aaron

[popular1119]

Dear Aaron,

I sincerely appreciate your patient responses. They have been incredibly helpful to me.

Moving forward, I will begin working on creating the Electrical Impedance Tomography (EIT) device. As I proceed, I hope to be able to reach out to you for guidance if I encounter any issues.

Thank you once again for your support!

Best regards,

Peng Piao

[RonAaron61]

Hi Peng Piao

Of course, anytime, I am happy to help. I hope your project goes as smoothly as you planned. Goodluck

Best Regards, Aaron