Sergey_P, I've moved this to a new topic because I'd like to discuss it more in-depth. What you are saying (especially in your last post) goes against everything I've understood about the effects of coil impedance. I'd like to start with the TX coil:


The best TX coil is an ideal...

9 round 0.8 wire 1.2x1.2 the other i have to find because i have long time to use...

Greetings to all the brothers who have successfully built the GS5 Lite.
I would like to ask you with respect.

On the GS5 Lite, does it work well across the delay range from 10µs to 25µs, or does it only work at a specific fixed delay setting? I would like to know.
...

What coil were you using? And what are the specs of the coil? Any pictures?...

Thank you Detectorist and GeoMax, you really put in the effort and have good intentions.

Hi,
Additional information for this project:
- The bipolar power supply allows to not use any pulse DC-DC converters. This allows to be achieved more signal to noise ratio with more simple GND traces and escape of using of special filters on the board. Not using of microprocessor for generate...

deltapulse i build is 2 meter deep...

yes but i don't have for i can build, you can share here? i want to build...

The drawings are correct....

Ultimately, the detection distance stopped at 30-40cm, and it only worked on large iron blocks. I will try to find an oscilloscope or frequency meter to readjust it.

Hello, the schematic diagram uses the hand-drawn version. Any part of the PCB layout is correct, I think. Just pay attention to the orientation of some transistors....

Hello ZOUjiarui, Would you be willing to share the schematic and PCB files? I'd love to build one myself so we can test it and explore it together.

​...

OK,thank you very much for reply .good luck....

Hi usefi5961,
As initial idea of this project, the DD coil used in this project have to be ready-made (made from DETECH company from Bulgaria in this case). The parameters of this search coil are very good (especially balance parameter is excellent). Maybe the details of making are secret (know-how)...

Excellent project and congratulation,can you please detail about making DD coil for this project and What is the maximum depth detection of the devices?

Congratulation Detectorist#1 & Geomax, thank you for this project!

Please share your opinions and experiences about new updated
Tarsacci models, thanks ...

Hi DIY people,
After more than one year of experiments with different schematics of bipolar pulse metal detectors with DD coil, me and GeoMax made one design with focus on relative easy repeating of the construction from relative less experienced DIY people. This is the reason for using of ready...

Hi ZOUjiarui,

my suggestion to you is get an oscilloscope and learn how to use it. Then you can find every wrong settings of your detector.

When we set pulse width to big, ended up with dead FET (if it's too hot) , we need to understand each section first. I did superscan not directly clone but modified minipulse to get working at 24V, with similar parameters timing freq, pw, etc It took time and no one will guide, i will not recomended...

possible, but need some adaptation for dual supply etc

Hello, my MOSFET is very hot, and the heatsink is generating high voltage, making a hissing sound. I think it's a coil overload issue. The DeepScan coil rating of 500uH and 1.2R should be correct; I'm not sure if this also applies to a 30cm coil. My coil measurement shows 520uH, and the inductance setting...

Hi...

Hi all,

the LTspice simulation confirms, that the complex nulling signal reference can be found easily by varying amplitude and phase of the two independent frequencies f1 and f2.
Four parameters for nulling:
A1 (amplitude f1),
Ph1 (phase f1),
A2 (amplitude f2),...

Hi all,

the next step is getting most out of the mono coil VLF system with active nulling and amplifying the difference. For active nulling, I have to use one of the line-out channels for the nulling signal. And I have to drive the LC-tank with single line-out channel this time (single...

The detector measures two parameters simultaneously: amplitude and phase. Changing the sensor's impedance in the presence of soil changes the measured values ​​simply by changing the distance to the ground surface. This introduces additional noise, reducing target sensitivity.
To reduce noise...

On Blind Squirrel it already has adjustable Tx, Delay and RX Pulse width; ...

I have not tested yet. I just got my batteries in and have to build a pack for it.

It's just a binary-weighted network, nothing unusual. 2:1 ratios: 4k, 8k, 16k, 32k. It produces 16 different gains ( 2⁴ ), one of which is 'all switches open', meaning 'Zero gain'.
If you want to replicate it with E24 resistors, use:
7k5; 15k; 30k; (30k+30k)
or:
(7k5//7k5); 7k5;...

If you ever want to send a video about how the device works and it isn’t possible to upload it in this forum, we can talk about it on my Telegram ID, and I’d be happy to do so.
amirali_sa_13...

Hello, Thank you so much — you’re really doing me a big favor. Yes, I really need the waveforms so I can get the device running. I built it a long time ago, but because I didn’t have the waveforms, I couldn’t get it working.
Please also send me photos of the device itself and the schematic,...

Hello,

The frequency setting is of course important. Many other timing parameters are also responsible for the entire circuit's functionality, whether your circuit works or not. These settings can only be checked with an oscilloscope. A very inexpensive oscilloscope is perfectly adequate...

Hello, the frequency of the MK2 version is adjustable, and I don't think 90Hz is that important. I replaced the chip; the 709 outputs 0V, and the sound after threshold adjustment seems normal. It squeals when the coil is touched, which I think might be due to coil mismatch. Please give me more help....

Hi Nasios,

It's good to have these parameters. However, without an oscilloscope, it's difficult, if not impossible, to adjust them. You also need to fine-tune the pulse width and other timing parameters to the correct values. Without an oscilloscope, that's simply not possible. It's like...

Hello, you have to 90hz the 555 and i think in the schematic write the coil 480uH 1.2R...

Hi Silver Dollar
The changes you made are interesting.
Did you test it in practice?​

Hi all,

I am looking for low noise jfets. I have finally found a relative cheap dual n-jfets (SMD).
NSVJ5908DSG5 (n-ch, 0.83 EUR)
It's noise figure is 1 dB.
It can be used in a fully differential stage or single ended and paralelled jfets.

I have not...

Hi Jafar.
I built the Delta Pulse years ago... it worked well.
If I can find the circuit, which is in the storage room at home, I will turn it on and upload pictures of the waveforms of its various points here.​

Hello.
Thank you for the schematic you provided.​...

Hello KT315
Yes, I know that the BFO system is an old metal detector.
I also work on the long range system... Years ago, Esteban said in the Long Range Farm that the BFO could operate in long range conditions.
Years ago, Wireless World magazine published a BFO design that showed 4...

In addition, the documentation website is available at:

https://soifgo.github.io/AnyScan209/

​

I actually tried twice to provide the correct link: https://soifgo.github.io/AnyScan209/. However, it seems that something—possibly an automated script or bot—is attaching the base URL https://soifgo.github.io instead, which leads to the incorrect 404 page.

I'm not sure whether this behavior...

Thank you Silver Dollar.. we could mod blind squirrel pulse too and change each width individually...

Second link show:

404

There isn't a GitHub Pages site here.
​

You'll have to explain more because I don't understand. In a circuit where the RX coil is loaded by a simple resistor (say, 10k) then the phase shift of the RX coil is practically zero even with a coil resistance of, say, 100Ω. Even if you lowered the load resistance enough to create a phase error,...

Under what...

Underground what....

Here's what the clock looks like;
...

Thanks, I've fixed the problem; after connecting the headphones, I realized the issue is a broken speaker...
Thanks.​

Thankyou I definitely will enjoy this forum
I'm in Queensland Australia on the coast and my dads cousin has a leas up north Queensland west of Cains which has a heap more but I'm more focused on my property which
I did find a couple of small nuggets years ago one was the size of a small...

AI ain't working good enough. Claude Code is giving me more serious answers.

A.I. = Absent of Intelligence
Let's give them some more years of developments.

LTspice simulation is more reliable. Even there is a misleading interpretation possible. I...

Hi all,

there is a big difference between Claude Code AI and Google AI (Gemini).
The latter one is much more halucinating, lying and confusing.
I have even tried the KIMI AI. It is making huge fatal mistakes.

I should try a different AI Query maybe....

Hello and welcome,

Where are you located and what color is the soil you will be hunting. Not to discourage you but flower gold is not really detectable. A vlf circuit is your best bet for fine gold if the soil is not too mineralized.

This project might be a good choice. The...

There's so many options!!!

I have found real small specks of gold on my property and my mate has a creek running through his property which is mostly dry that may have something in it too.
I'm looking at building a detector, just the schematic and maybe a PCB if available as I have...

The electromagnetic characteristic that distinguishes one substance from another is phase. If the phase of the detector's receiver impedance is indistinguishable from the phase of the surrounding soil impedance, they have no effect on each other. To reduce phase noise in the detector's receiver when...

I uploaded a new video to compare the versions available online, which is what I was missing since I had only uploaded everything about the version I modified.

This time, I'm testing the full version 3.35 and the version I edited, which is 3.35 GT.

After testing, I realized...

This detector is sold here under a different name.

Oh,.... If you want to fine-tune your detector, an oscilloscope is an indispensable tool.

https://www.geotech1.com/forums/member/6090-pasha Hi. Could you share the HEX file for the Delta Pulse 3 with me?​ [email protected]

Hello, I don't have an oscilloscope, so I can't monitor the waveform frequency at the moment. Its voltage is ±4.9V, but at -12V it only registers 11.7V. It seems very sensitive to static electricity; if a finger is near the audio jack or the coil, it causes interference. I'm trying to resolve this...

Hi all,

the AI is obviously preventing more forum discussions. It seems, that more people are asking the AI instead of asking the forum contributor experts.
Same happens to Github & Co and other forums too.

Analysing a circuit with an AI is still an issue. The AI...

Hi ZOUjiarui,

I think the coil induction is to high and the damping resistor is not right for your coil. I would reduce the inductance to about max. 350uH​ and adjust the damping resistor accordingly. If you need more power you can increase the TX pulse width slightly.
What are...

.

Sorry i can't remember exactly wheter to give more or reduce turn i thrown so many many coil back then.... anyway after it done at 2 meter for 1m coil on the field in some areas if it hits large wall below (a brick wall left under the ground i don't know why but it make sound) after bring excavator...

You need to start with desired coil diameter first and then adapted R damp for that coil, try to lower inductance/turn this part to me was painful

https://youtube.com/shorts/eeS-h0Gzg...st4VSdhcMu3wsh

Hello everyone, I need help from those who have successfully obtained the desired sensitivity. I'm unable to achieve the highest sensitivity setting. The inductance is approximately 520uH, 1.2R. Thank you very much.

Some people have said the LM386 adds to the warble tone and using a two transistor amp makes it work much better with a smooth threshold. In looking at the proto scheme and the board the 2 transistor circuit is already on board. So we can just disable the LM386 and take our audio from the last transistor....

I am selling a TDEM time domain geoelectrical prospecting system, with transmitter and receiver, due to lack of use and as new. The transmitting loop is 50x50m, the receiving loops are 10x10m and 1x1m. Investigation depth up to 300m. Lithium batteries, 11-inch TFT display, data acquisition software,...

Hi Eduardo. I followed your instructions and instead of the 2.2k resistor, I used two 2.2k resistors in parallel, which have good power and a value of 1.1k. You were right, it detects two cents more and the 7912 regulator runs cooler. I left the device on for 5 hours continuously and set the battery...

make Barracuda. it is very small compact board with ground compensation. you waste a time on a BFO without result.

Hello. Yes, its differentiation works by changing the tone of voice....

Eduardo, I thank you. I will do this test as soon as possible....

Hi David. With the new 40cm diameter coil, you'll probably need to change the damping resistor value, as this can sometimes happen. The NE5534 offset setting, the coaxial cable you're using, and the main sample delay setting can also influence the results. There are many factors to consider. Theoretically,...

Hello David222
This might be a classic question, but...
Does the GS5 discrimination work well?
Best regards,

Gurdal​

Hello friends. I have a strange problem. I made the GS5 Eduardo and chose its coil of 2 ohms and 412 uH. I chose a frequency between 1300 and 1500 Hz. Because more than this the 7912 regulator heats up. In this range its performance is better than all pi devices. I used 20 meters of enameled wire with...

Hi all,

BTW, here is the PI metal detector I have mentioned published in Elrad dated to 1985/9.
Link: https://www.mikrocontroller.net/atta...AD_1985-09.pdf

Don't waste your time with BFO's. They are not useable in the field.
Azi...

Hi Eduardo1979,

thanks for the reply.

Hi Geomax. The GS5 Lite's frequency is adjustable from 2.6 to 3 kHz. I set mine to 2.8 kHz and the TX pulse width to 100 µs.

I assume the GS5 has the same frequency, or very similar. The GS6 has the same frequency as the Surf Master Pi, around 615 Hz.​...

TL081 -o-scope picture was been done with US made opamp, I desoldered it from old board. you see TL081 has lowier slew rate but working good.
try to search oldest LF356 at ebay. maybe made in GDR, Greek, etc. I had bought nice LF356 from greek onetime....

Nicely done! Next time you do a video, also show the response to ferrite. This helps provide a reference for all the other responses.

Maybe you have a fake Chinese IC....

“What could be the problem with my pre‑amp? The input of the pre‑amp looks like what you showed, but the output is not like your example and has errors...

Hi Eduardo1979,

What is actually the operating pps of the GS5, GS5lite and GS6?...

Gs-5 lite...

Ok....

Thanks. I built the GS5litle that you posted on the forum. And it works fine. Of course, it took about a month to build and configure. Now I want to start this circuit....

Hello. The PCB circuit is correct, as mentioned in the previous answer. I think this question is redundant and there's no need to repeat things so many times. The difference between the GS5 and GS6 is that the GS6 is deeper for high-conductivity targets due to the lower operating frequency of the detector....

Hello Eduardo. I hope you are well. I am going to build this circuit. But before that I have two questions, please answer them. Is this pcb correct and does it work? And how is this pcb different from GS5litle in terms of depth and quality in general. Forgive me if my spelling is wrong. Thanks....

This is the circuit

Here is a photo showing both hardware revisions of the detector: the original THT prototype and the latest compact SMD version.

The current hardware is based on an ESP32 microcontroller and uses an MCP3202 12-bit ADC for signal acquisition. The electronics are now fully tested and working...

Hi all,

the book "Andreas Gatowski_Schatzsuche mit Metalldetektoren_1990" was my first book on metal detectors and I loved it.
I have built the BFO. It is a toy and can not be compared to a serious metal detector for field use of course.
It is better to build the PI...

-VB...

The current of the collector should be a little higher in the case of bst 52 is 1A darlington so that the transistor absolutely does not overheat and the speaker does not break. But I think Karlo's proposal might be better.. ...

Very thanks dear Carl
GND is generated in IDX by u7-pine 7.
In your LM386, gnd is the pine 7 or _VB?...

Thanks
You right, my noise is low by the changing.
I can not understand bst 52....

An 8-ohm or 4-ohm speaker might be louder. However, the speaker is DC-coupled and you run the risk drawing a lot of static current. Here is a simple circuit I used in ITMD3 projects:

​
In your case, VTX is Vbatt, VCC is your "+" supply, and Q3 (your Q4) can remain as an...

Those capacitors make the signal cleaner. Reconnect the pin point and adjust the pot trimmer to barely audible and leave the setting like that. You could also replace the input number 5534 with AD711. As for the sound Karl I know he will give you good advice. My suggestion is to put an 8R speaker and...

Hello everyone,

Some time ago I started this thread looking for collaborators to build a modern IDX Pro metal detector based on an STM32F411 and an ESP32.

I wanted to share a quick update: the hardware is now fully working and has been successfully tested. The detector communicates...

Hello dear carl.
Please forgive me, i have a request.
Please see IDX schematic audio part, post #4378.
Unfortunately its audio level in speaker is very low.
Is it possible to help me how to increase its audio in speaker?
I tested it with 15, 25, 150R speaker.
Tha...