My Pulse Oscillation detector project.

[Teemo]

Hello!
This is my first post here. I want to share my self designed detector project. It is a 8pin PIC microcontroller based detector.
It is not exactly PI, BFO,VLF, Delta pulse or PLL it is maybe PO.
It is super simple to build. Uses simple classic mono-coil (as most PI detectors). I find its sensitivity quite good, at least for such a simple circuit (and not so simple firmware).
I tried to put all information needed to build a copy of working detector to my website.
So check it out, if you like it:http://digiwood.ee/en/

I'd appreciate any feedback.

[mindfree]

This is just what I was looking for to learn more about metal detectors.
Waiting for the source code.
Thanks for sharing!

[Carl-NC]

This is a nice, clever design. You should make some depth measurements with common coins, it would be interesting to see how this approach compares.

[mickstv]

Website doesn't open for me.......

[Qiaozhi]

Website doesn't open for me.......

It doesn't open for me either.
The IP address is 212.47.211.148, but it doesn't respond to "ping".
Looks like the server is down.

[Teemo]

Thanks all for replays.
I guess I must change my web hosting provider.
Teemo

[6666]

teemo
you can post files on here as attachments.

[Qiaozhi]

Thanks all for replays.
I guess I must change my web hosting provider.
Teemo

Please post the information here.
There is a Manage Attachments button further down the page when you make a new post or reply to an existing one.

[mickstv]

It doesn't open for me either.
The IP address is 212.47.211.148, but it doesn't respond to "ping".
Looks like the server is down.

Thanks Qiaozhi.

[Teemo]

Hi
So here I try to post schematic, hex file and the new thing --partslist.

[Aziz]

Hi
So here I try to post schematic, hex file and the new thing --partslist.

That's a mini TEM (tuned electro-mag.) transmitter.
Aziz

[Aziz]

Hi all,

according to the schematics and the processed information (debugging the hex code isn't necessary):
It is a BFO. (Or some kind of frequency shift detector.)
Aziz

[joop]

So the search coil together with the 47nF capacitor form a resonant circuit which is excited by the FET. A change in amplitude is measured at the PIC input. A resonant PI?

[Aziz]

So the search coil together with the 47nF capacitor form a resonant circuit which is excited by the FET. A change in amplitude is measured at the PIC input. A resonant PI?

No, you can't measure the amplitude as it will be clipped by the diodes. The coil induces a high voltage. It is typically driven at approx. resonance frequency of 77 kHz. The only way is to detect the frequency and mix it down by an internally reference (a simple xor) and put the mixed output to the piezo element.

I like it's simplicity.
Good work.
Aziz

[joop]

ah, the clipping diodes, of course... But amplitude could still be measured after a time delay when amplitude is below the clipping voltage...