Custom High-Power 24V Pulse Induction PI Detector Circuit Review

[Detectorist#1]

Hi Aashif,
I'm ready with the first variant of the schematic of "High TX Power PI Detector". The real tests on the ground will point some changes, as usually. My general idea is to design schematic solution with easy expandable TX power without changes in the design of the PCB. The different TX power will be received only with changes of the values or the types of some parts. It is possible to use different type ( with different price) power switch transistor (standard NMOS, SiC or IGBT) with price from 3USD to 20USD and with voltage from 600V to 2000V. Used IGBT transistor haves a price of 3USD.The design uses search coils with 300uH inductance and 1oHm resistance for every used size. The first variant uses search coil with 3ft diameter. The design haves serious defenses: from over-voltage and over-current of the power switch even in case of using of search coils with lower inductivity or even with short circuit in the search coil circuit. It is not easy to make decision for the useful range of the RX delay for this project - the tests with real targets on deepness 10-15ft needs serious efforts.

[Aashif]

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[Aashif]

Hi Detectorist#1,
Thank you so much for the Rev.A schematic! The design and the built-in protection features look absolutely brilliant. I will use this PDF to carefully study the circuit and learn how the building blocks connect.

Since you mentioned that the 10-15ft depth tests will require serious efforts and might lead to some fine-tuning on the ground, I am more than happy to wait. I will hold off on any final routing until you have completed your tests and are completely satisfied with the results.

I am in no rush at all. I just want to follow your expert lead step-by-step to build the perfect "BRUTAL" machine.

Eagerly looking forward to your testing phase!

Best regards,
Aashif

[Detectorist#1]

Hi Aashif,
The contents of your comments point that you continue to wide use of AI. I hope, this will help to you to reach your aim. I have the friends that wont to use deep searching PI MD and you are the reason to my start to design such type of detector.

[Aashif]

Hi @Detectorist#1,

Yes, you caught me! English is not my first language, and I want to make sure I understand your brilliant technical designs perfectly and communicate my thoughts clearly to you without any language barrier. So, I am using AI as my learning and translation assistant. I hope you don't mind! It has been incredibly helpful in understanding the "Positive Ground" logic in your schematic.

I am deeply honored and touched to know that I was the reason you started designing this high-power detector. That means the world to me! I am also very happy to hear that your friend will benefit from this deep-searching PI MD as well. It is amazing that our discussion is going to help others too.

I am setting up EasyEDA now and will practice mapping the THT components for the power supply section, just to keep my hands busy while I eagerly wait for your ground test results.

Thank you again for your incredible support and dedication to this project!

Best regards,
Aashif

[Detectorist#1]

21-st century!

[Aashif]

Detectorist#1,
Haha, exactly! Modern tools for modern times.

However, I truly believe that while AI can translate words and explain basic concepts, it can never replace the years of hard-earned experience, intuition, and the sheer genius of a true expert like you.

For example, I was studying your schematic again today. The way you used the "Positive Ground" architecture to isolate the heavy TX power noise from the delicate RX signal (using the separate grounds that meet at the battery) is nothing short of pure art. AI can explain how it works, but only a true master could have designed it!

In my culture, we have the highest respect for teachers and mentors who share their wisdom without ego, and we call them "Guru". Your patience and your willingness to guide beginners like me is truly inspiring. I consider myself very lucky to be learning from a Guru like you on this forum.

Thank you for being such an amazing mentor. I am firing up EasyEDA now just to practice my routing skills with this Rev.A schematic. I will patiently wait for your final ground-tested version before I start building the real masterpiece!

Deepest respects,
Aashif

[Detectorist#1]

Hi Aashif,
Before my retiring, I was for 18 years teacher in our technical university for design of digital and analog solutions. I just continue to do this.

[Aashif]

Hi Detectorist#1,
Wow! That explains everything! No wonder your designs are so flawless, your knowledge so deep, and your explanations so patient.

I genuinely felt like I was talking to a real professor, and it turns out I actually am! It is a true honor to be your "student" on this forum. Thank you for continuing your noble work of teaching and guiding enthusiasts like me even after your retirement.

I will learn as much as I can from you!

Best regards,
Aashif

[Detectorist#1]

Hi Aashif,
After the real tests of some modules, I made changes of values of some parts.
Attached is the current version of the schematic.

[Aashif]

Hello (@Detectorist#1),
Thank you so much for this golden update! The fact that you are putting in the hard work to physically test the modules before finalizing them shows the true dedication of a master.

Your timing is absolutely perfect! I was just about to go to the market today to get a large A3-size color printout of the schematic for my workbench. Now, I will print this new Rev.A1 version instead!

Before I start my practice in EasyEDA, I am going to carefully compare the old Rev.A and this new Rev.A1 to see exactly which component values you changed. As your student, trying to understand *why* an experienced professor changed a specific value after a real-world test is the best analog design lesson I could ever ask for!

Downloading the new masterpiece right away. Thank you for everything!

Deepest respects,
Aashif

[Detectorist#1]

Hi Aashif,
Attached is the design of 3 foots round mono coil 300uH 1 oHm. I hope, these days I will finish this construction. This will allows to made the tests of the power TX stage.

[Detectorist#1]

Attached is the next, more close to practical realization, variant of the schematic of the project. Added on the schematic are connectors on the PCB for external to PCB parts. The power solution is realized with popular AA size LiPo accus. Added is DC-DC convertor for generation of minus 24V voltage. Also popular chargers with 0.8A charging current for 3S LiPo accus with equalization have to be used. Very cheap models are "Hobbyking B3AC" and "IMAX B3 Pro". The current limit thru power switch is fixed to 10A. The voltage limit depends from the voltage of the TVS diodes and have to correspond to max DRAIN voltage of used transistor as power switch.

[Aashif]

Hi Guruji (@Detectorist#1),
Thank you so much for the Rev.A2 schematic and the 3-foot coil design! The addition of the DC-DC converter and making it compatible with 3S LiPo chargers is a brilliant practical upgrade.

I have downloaded the new files and will update my practice workspace in EasyEDA to match this new power section. I am eagerly waiting for your real-world test results of the power TX stage with the new coil. Take your time, Guruji. I am learning a lot just by watching your design evolve step-by-step!

Best regards,
Aashif

[Detectorist#1]

Hi,
Now, I publish the current schematic of one high power PI detector with ground balance feature for the thrill-seekers in forbidden places. The search coil have to be 1x1meter with 300uH inductance and 0.4oHm resistance. The energy in 3pcs. LiPo 18650 accus is enough for all day searching. The project is open for any ideas for improvement.