felezjoo PI(the best pulse induction metal detector that I made until now)

[ivconic]

[ivconic]

[ivconic]

The only thing I don't like about the pictures is the use of piezo speaker, worse; it is soldered to the pcb!
The speaker gives a much richer sound. The author advised a piezo and not a speaker because of the interference a speaker can introduce to the detector.
But this is very easily overcome if the speaker is installed on the detector box like this;
that it does not share the same "volume" with the rest of the electronics.
And if the position is chosen such that "waves" and "vibrations" do not go directly to the pcb.
An even easier solution is to install the speaker in a smaller box on the stem part that goes under the elbow, where the battery is usually located.

[kt315]

And the use of LF357 in a round, "military standard" package.
There are some of these in my local stores, but they are very expensive!

do not worry. chineses had copied the glass metal package too and sell. some sellers on ebay i see re-sell them like 'vintage authentic'.

[ivconic]

Not all Chinese copies are bad and fake.
This summer I bought some very "delicate" chips on Aliexpress. With premeditation that they are fakes and that I wasted money.
It turned out the opposite, the copies work identically to the originals! Fortunately for me.
E.g; the main component in Depth Doubler, the chip, which is very hard to find elsewhere.
There are tons of it on Aliexpress and it's cheap.
Oscilloscope analysis showed that it works 100% like the original.

[MDfanatic]

What I found peculiar about the board you posted ivconic is that it's using the exact same track length and width for 12V as the original board. Hmm.
By the looks of the board and the url on the images I suppose the board must be by Mr. Hamid so he must have a very good reason to keep it exactly as in the original.

I guess he really meant "according to spec"!

[useus]

having the counter version, the time has come to reflash the mcu but I had a surprise, after reprogramming it, the counter remains functional (I have 20 uses left). Yet last time I had no problems, I use avrdudess setting erase flash & eeprom and set fuses. what can cause the problem? Thank you!

[ivconic]

having the counter version, the time has come to reflash the mcu but I had a surprise, after reprogramming it, the counter remains functional (I have 20 uses left). Yet last time I had no problems, I use avrdudess setting erase flash & eeprom and set fuses. what can cause the problem? Thank you!

Counter value is stored in eeprom.
Erase the eeprom completely.

[useus]

Counter value is stored in eeprom.
Erase the eeprom completely.

thanks, I forgot about this step

[ivconic]

What I found peculiar about the board you posted ivconic is that it's using the exact same track length and width for 12V as the original board. Hmm.
By the looks of the board and the url on the images I suppose the board must be by Mr. Hamid so he must have a very good reason to keep it exactly as in the original.

I guess he really meant "according to spec"!

I will become boring to repeat; but really everything possible with Atmega has been done here.
With so few components and such a modest processor; the detector works surprisingly well.
The author himself mentioned several times that it is very important to stick to the specifications strictly.
In the process of writing and tweaking the code, the author had a very narrow space for successful completion. So everything matters.
I have made no more than a dozen of these detectors, and now I have one finished on my desk.
FelezJoo has become a must-have detector and a permanent member of my collection.
In the process of making and testing the things done so far, I noticed and it was proven to me that the author was right and that he meant everything he advised most seriously.
Successful construction is therefore more difficult, even though at first glance the detector looks very simple and easy to make.
But if you want to end up with a very good detector that is very usable; everything said must be respected.
In my opinion, the most delicate part is the LF357, that is, the quality of that opamp. There is no need to save money. You need to find the original in the metal case.
Considering that it is an obsolete opamp, it becomes more and more difficult to find an original and easier and easier to find a bad copy.
It would be good to revise the project with modern components. But without the source code it won't be a safe business.

[Altair]

Hi Ivconic,
what firmware version do you use in your Felezjoo build?
From your esperience, could you confirm if the no counter firmware version is unstable and it's noisy?

[ivconic]

Hi Ivconic,
what firmware version do you use in your Felezjoo build?
From your esperience, could you confirm if the no counter firmware version is unstable and it's noisy?

I didn't notice that the latest V3.35 is unstable and noisy.
Yes, since it came out; I am using the latest V3.35.
Some prankster is trying to make a deal by renaming one of the versions to "V4"... which is not true, there is no such version.
V3.35 came directly from the author as the latest version.

[ivconic]

In the beginning, when I was working on the first few devices; I got in touch with the author and had several email correspondences with him.
The man was kind, accommodating and selflessly helped with various advice.
I tried to extract only the most important things from those correspondences and put everything in one text.
Which, I hope, will serve all of you as a good help in building this detector.
Try to find your way through the text because I'm sure you'll find answers to all your questions.

[Altair]

Dear Ivconic,
many thanks for reply and sharing your remarks!
I have appreciate that!

[pito]

the best pulse induction metal detector that I made until now = Is there a proof of that = video ?
I saw this one = not imprest , https://www.youtube.com/watch?app=de...ature=youtu.be