...

https://youtube.com/shorts/BIN0eoTV_...uSPkEvFrnzR8_9I also have it in the country, but somewhere on the flash memory I deleted a lot of recordings from the channel, but it works much better than many famous famous brands.I made the bipolar only with a large concentric coil of 50 cm.. For larger deep...

Do you have a video clip of Cesar detecting a coin in the ground?...

I’ve been digging deep into the LTSpice simulations for this ZP (Zero Point) servo and a few major things have clicked. The defining feature of this design is tying the coil to a low impedance at the end of the flyback, which is a double edged sword.

The impedance the coil sees is just...

I wrote to [email protected], so you probably have a typo there....

I don't see any messages from you in my DMs. You can also email me at: [email protected]...

Hi all,

I have replaced the resistors R1 and R2 by 2 x 10 nF SMD capacitors now (option 3). It is working much better now.
I have even used the 0805 SMD types. A copper tape with adhesive film put onto a small paper or cardboard stripe it is quite manageable.

...

First photo Cesar with three channels modified power supply 80vpp ! The second is a bipolar scheme on the subject of bipolar .....

It's a nice project and I've emailed you a few times about collaborating but haven't received any response....

...

Here is a pdf of Altra you can test a bipolar generator...

I wanted to show how I actually work on this project day to day, because the workflow itself might be more interesting to some of you than the schematics.

1. Firmware in VS Code with the STM32 extension

The entire firmware (STM32G474 main board + STM32G071 probe) lives in a...

Where you marked +5v is 10v and - 9v is - bat. I have a scheme with the modification of the transmitter, but with three channels, the third ch is used for the pin point, and here I drew only the transmitter with the change to rx ca30xx, it turned out to reduce noise compared to ordinary transistors,...

Hi Repwoc and Marchel,

Marchel is spot on with the dead-time suggestion. If the dead time is too short, you get shoot-through currents in the H-bridge, causing large current spikes from the supply. These spikes easily couple into the RX path as broadband noise.

Besides optimizing...

The video is a test version—to see what it does.
All my videos were filmed online—before that, I didn't know what I was doing.
Google Translate does not translate correctly.

...

Thank you, Carl NC. I was glad to assist you. I hope we continue to work together in the future.

Have you tried changing the Dead Time in the timer settings ? maybe that would help....

Try this:
​...

OH!!!! a CESAR generator ...

This is the first time I've seen this version of CESAR.

Thank you very much, Orbita, for sharing this LAY file.

If it's not too much trouble, do you have the schematic for this PCB?
Can the same coil from the Servio más Buscado (SMW) be used?
Although I see that...

I'm working on a MF design with a similar tx to yours. I've chosen different frequencies to start off with - I've gone for 3 kHz, 9 kHz and 27 kHz - using SHE PWM to generate them, ie 3 kHz fundamental and 3rd and 9th harmonics. 5th, 7th and 11th harmonics are nulled. I'm using a full H-bridge to drive...

[QUOTE=pechkata;n450736]

[Hello, Ruben.
Yes – a capacitor in parallel to determine the sweep.
The MOSFET doesn't matter—it doesn't consume power.]



Although I didn't quite understand your answers, I think you stated that you used the same Sascho...

Yes exactly IRF640 and IRF9640....

Hi Carl​ I want to try the TDI ground balance, but on your bipolar circuit. Can you tell me how I should connect them correctly? Thanks. ...

Some features are not available until you make an initial posting, so try now....

I think it refers to P-channel and N-channel MOSFET transistors. IRF740 and IRF9640. If we zoom in on the photo, we can see that the terminals are defined as GDS...

Hi pechkata,
The mystery with the real schematic of this project continues to exist. On the PCB, the marked in yellow zones for transistors from Ruben2000 was named as PNP and NPN. But you mention for them as MOSFETs and TC4427 driver usually controls MOS transistors. Full mystery!

Hello, Ruben.
Yes – a capacitor in parallel to determine the sweep.
The MOSFET doesn't matter—it doesn't consume power.



The cable to the ignition coils is also important.
The shielding connects to the battery negative terminal.

...

Cezar 80vpp /tx...

No more avaible. Post can be deleted

Hi pechkata!

Thank you so much for sharing your files!

I wanted to ask you two questions:
1. What MOSFETs did you use in the circles marked in yellow?

2. Did you use the same coils designated in Sascho's schematic?​ ...

Hello everyone,
​I am new here and I am still learning how to navigate the platform. I can only see the posts, but I am unable to view members' profiles, see their work, or initiate private conversations. Could you please let me know if I am missing something, or if there is an issue with my...

I'm testing the Felezjoo discrimination and I've noticed that if you use the Iron Rejedt setting of 25 to 30, only copper and silver enter the non-ferrous zone. However, this only applies to copper, as silver, to truly enter the non-ferrous zone, needs to be very pure, between 725 and 999. Lower-quality...

Greetings.
Because I am not satisfied with the current op-amp I am using, I have ordered an authentic/genuine NE5534. Once it arrives, I will test and verify it, and then share the results and data. I am also still in the process of testing. Thank you to all the teachers and mentors on the...

hello sir you can shear the link again because don't work? thank you...

Hi all,

ok, the resistors R1 and R2 in post #397 are causing too much energy losses. I am going to change them into equivalent impedance Z with two tiny SMD capacitors.
After comparing three different equivalent circuit simulation configurations, they all are producing same target...

Hi all,

I have tested the last idea. No good.
The sensitivity suffers compared to the simple capacitive drive and capacitive output.
The spice simulation does also says the same.

Now lets focus to the better method.
Aziz

You can still buy LM394s from ALFA REPAR; I bought 20 from them, and they are reliable....

Thanks dear Carl.
My problem is solved.
My GB-Pulse delay is working, problem was for frequency of IDX.
About removing ferrite with coil, do you have a distance suggestion from coil? Which distance is better?5cm, 10cm or etc?!...

For GB to work, you need to get a timing pulse like this:
​​
where the top waveform is a ferrite signal at the preamp output and the bottom is the clock signal at R42. Notice that the clock edges occur at the signal peaks....

Quick update on the multi-frequency VLF I've been posting about (STM32G4 base, 3 simultaneous tones at 7.8 / 23.4 / 39 kHz via SHE-PWM). The coil/analog side is still a couple of months out, so instead of sitting on my hands I built a physics simulator and I'm developing the whole "spectral fingerprint"...

Hi all,

I am going to test the latest version of the dual frequency mono coil VLF soon.
The very low impedance path to the differential signal is very good to improve the SNR.
A few turns for the additional primary coil will reduce the total parts count and gives more benefits....

Hello, Eduardo.
I have already shared them.
There are circuit boards—but no schematics....

Hello Altra.
A processor schematic is pointless without a hex file.
We won't take the schemes with us to the afterlife.

Still, thanks for the idea.

Only the transmitter is bipolar and the processing is VLF at your Pecka, here is a scheme from 2016, similar except that there is no delay during the cycle, i.e. bipolar pulses.-8v =bat negative....

Hi Pechkata.
Thanks for the Hybrid generator schematic. If it's not too much trouble, could you also share the schematic for the AF108 Bipolar generator that you use in some detectors? I have the ITMD3 Bipolar-PI schematic, but it uses a microcontroller, and I'd like a Bipolar pulse generator...

Hello.
This is the basic scheme.

...

Metal Detector Studio - v0.13.0-beta out.

A quick update on my bench/lab suite for developing VLF detectors. What's new in this beta:

- Coil design tab - design a search coil before you wind it: DD / concentric / mono, both TX and RX windings (each with its own turns and wire...

Hi pechkata,
The schematic of NIVA HYBRID continue to be top secret. If you have respect to our common efforts in DIY PI designs, post the schematic.

I tested C22 with 10P, 560P and 1n.
All result is identical and can not remove ferrite.

Ch2 = TX
CH1 = RX
My Scope can not show lower than 200mV.
If i decrease RX amplitude, my sensitivity will be higher.
But since you can not see in scope, i have to increase...

Thanks dear Carl.
I nulled coil with very nice depth but the GB can not remove ferrite.
I checked GB pulse-delay on scope. The pulse move but the moving is very low.
Do you have any suggestion values?...

The pot will change the delay, not the pulse width.

If you can't remove the ferrite, you may not have a sufficient GB range. Try using a different value C22 (higher, lower) and see what happens....

There is also a Pulse version of this. ...

Is it possible to guide me how to cancel RX and TX using AC multimeter?
I can not remove ferrite with any cancelling rx and tx.
I am using 4066 and TL064.
I nulled coil and my depth is nice but i can not remove ferrite...

Thanks.
Have you its PCB ?

About my PCB, please see the red circle.
I have pulse in scope, but GB has not any affect on Pulse width.
I think that changing GB pot must can decrease/increase pulse width.
...

Just experimenting with different concepts - the kind of thing I drop one day and might come back to the next

There are a few newer ICs that could potentially bring some benefits, but it's often the case that the more complex the part - like the DRV8872 I mentioned -- the more it becomes...

Perhaps some day pechkata will publish the schematic of NIVA HYBRID, just as eduardo1979 does, for people who enjoy DIY projects.

Classified! Classified! Classified! Classified! Classified!

​...

i have two versions of the hardware ( stm32 and ESP32 based ).
The android app talks to either via blue tooth or USB.
I have been hammering the ADC and DSP code on both hardware platforms to achieve some decent noise floors.
At the moment the ESP32 solution is leading with a noise...

Never mind.



Perhaps you could have mentioned that when I asked "Are you still using this design?"....

Obviously, the schematic is top secret and will be used for making of a big money some day.

No, impossible!.
No way!
It can't be done! Not in 100 or 1000 years!
Your math is cheating you.
Your AI is halucinating.
There is no free lunch!
All free lunches had been eaten up by me.

Enough motivation now?
Aziz...

Well ok,

lets get much smarter than the AI.

Based on the idea of post #365 (the magic cheat):
https://www.geotech1.com/forums/foru...-etc?p=450060#...

Hello. This is the final schematic that I've used for a long time, and it works best. The coil is also very important....

I connected scope to U8-Pin7 (GB pulse).
I change GB pot, but no change to Pulse-width GB in scope.
...

Hello
Dear eduardo
I balanced RX and TX as follow:

Please see schematic (red circle), i saw that people fixed R43 as 2.2K and removed VR3 ( done as shorted line).
I also have done this, but i can not remove a ferrite using GB pot.

In addition, my sensitivity...

Okay. Thanks anyway. I was particularly interested in the schematic for the bipolar pulse generator, which I see you've made with a TC4427 and a TL494. I'll try to draw a schematic based on the PCB layout.

As I mentioned before, this approach works fine in commercial detectors just take a look at Carl Moreland's fundamental patent US20180372904A1. It's a standard bridge topology. To improve the switching characteristics, you could simply add a 4.7R - 20R resistor to each gate.

However, this...

Hello, Eduardo.
There is no scheme.
The yellow probe is on the x10 setting.


...

Hi Pechkata.
Thanks for posting the PCB design and the video, which I really like. It would be very helpful if you could also post the schematic, so I can understand how the detector works. I'm especially interested in seeing the PI section of the detector. Did you use the AF108 bipolar configuration?...

...

Yes, but you have the gates for the high- and low-side mosfets tied together. So when the signal flips one mosfet will turn off and the other will turn on. There's no way to control the dead time. If both mosfets end up being switched on during the transition you will get shoot-through....

Hi Orbit,

Thanks... I was just curious and thought there might be a good reason for it.​

There is nothing special about it at the moment when I was drawing, so it was convenient for me because the pcb looks as small as possible. If the test version would have fixed the noise problem I had a different layout but since it works as expected I didn't send another version to be done....

Hi Orbit/Altra,

I’ve taken a second closer look at your PCB and have a question about it. Is there a reason why the tracks circled in blue are routed at 90-degree angles, even though all the others are routed at 45-degree angles? Or were they simply overlooked during the cleanup process?...

Hi GeoMax thanks, I think the Altra design is even nicer!And very importantly, the device works great in the field....

Hi Orbit / Altra,

Nice clean PCB design... Looks very good...

Bipolar hybrid detector pi region - ib region with geb +disk. With DD coil....

You're absolutely right, that 220uF capacitor is meant to decouple the MOSFET supply, not the gate driver. And thanks for pointing that out - I just noticed the polarity is wrong on the schematic as well. ...

The whole control scheme is handled by the STM32's HRTIM peripheral. In the firmware, I configure the dead-time parameters between the TX_PWM_A and TX_PWM_B signals with immense resolution....

Bravo moodz!
You’re a worthy successor to ivconic. Now *that’s* how you warm up the crowd....

I'm not sure why you need the 220 uF cap to decouple the gate driver (and is it the right way round?). Did you mean for this to decouple the supply to the mosfets?...

​...

Yep, this is the last step. But I want to use a cheap tinned copper litz wire first. I have a 100 m roll. I can experiment with it before I use a true HF litz wire....

OK - so are you saying that "nanosecond-precision Dead-Time control" is no longer needed?...

To reduce the effect of proximity, you need to use a litz wire.

Hi all,

I have been chatting with the AI.

It says, that proximity effect is the most degrading factor in my mono TX coil. The skin effect is generally not much relevant (only 1 - 2%, 1.01 - 1.02 times) and can be neglected. Whereas the proximity effect can cause 3 - 5 times...

can you see anything in that black screen ?
compare
​...

A few days of working with Fable confirms it’s a very solid model. I’ve integrated feedback via MCP and tools into my existing software to connect with a real-world device. AI-to-hardware integration is reaching a whole new level!
Now Fable does more than just write code it actually operates...

Yes, we are. It's a proven approach that's been successfully used in commercial projects. Of course, I'll consider other options as well. So far, the priority has been developing Metal Detector Studio, as without it the project wouldn't really make sense.
​...

Hi Gents,
How is it going...?
Have been patiently reading your posts so looking forward to see some video soon..?...

Hi. I have seen these. And Jose said that this circuit needs some changes, but the changes are stated in a scattered manner. I have read this thread more than 4 times. I apologize for the bad English. Thanks for the file and the effort you put in. I thank all the friends present in this forum for their...

Here is the short cable I built. The correct connectors are those ( https://pt.aliexpress.com/item/1005007358415419.html - GX16 5 pin reversed), although I reused the original ones that where in good condition.

I used high voltage heat shrink (they have a thick wall).

Thanks...

Are you still using this design? ie one dual gate driver chip with each output driving both high- and low side gates of one leg of the H-bridge?...

thanks.
problem solved, +8V line in pcb-jumper had error....

Top down view:
...

Hi all,

I am not happy with my ribbon mono coil yet. Too big and too much weight. The PVC insulation adds a lot of weight to the coil. The coil bundle might produce microphonic effects (it is not a tight coil bundle yet). And it isn't easy to tame the coil bundle. Finalising the coil into...

On p159 the left-hand drawing should say r/2, not r/4:
​...

you have to look BOM file on Bara. so will see
40106 CD40014 SN74HC14
CD40106 MC40106 TC40106
HHF40106 HCF40106
CD4584 MC14584 TC4584
AN6559 K561TL2 K1561TL2​...