My Pulse Oscillation detector project.

[mr.sneezy]

Hi bernte_one.
I see you have used a ferrite coil with Teemo's design, which answers a question I had about that.

What I have in mind is to retrofit a cheap Chinese TX-2002 pinpointer with Teemo's circuit and see how it does. The TX-2002 is not a very nice thing (mine at least) as sensitivity is poor (like 10-15mm for a coin) and it's a motion circuit so you must keep moving the pointer to pin down the target (sort of counter intuitive).
I have picture of the TX-2002 circuit board if anyone is interested BTW. It's got a LM358 and a CD4011 as the core components.

The good thing about the TX-2002 is that it has a single wind ferrite coil of around 2 ohms, in a nice water proof tube, inductance is unknown at the moment (till I borrow a meter). Hoping it may be usable with this PIC circuit.

Cheers,
Martin

[bernte_one]

hello martin,

where did ou come from?

would be happy if you could post the tx-2002 sheme and maybe good quality pcb pictures in a new thread.

if you got a L- meter check if inductivity is around 150-300µH i think all in this range can work somehow
i wind yv wire 0,5mm core directly around a 8mm ferrite core
compared to others it has good sens on small items

please post your results
good luck

[mr.sneezy]

No problem, I'll start a new thread with the info I have. Schematic is not trivial, there is a lot more in this detector than say a Cen-Tech pointer. I'll photograph both sides of the PCB while I have it apart.

Where did I come from ?
Not sure what you mean, but I've been around on the web a bit, mainly in RC and PIC micro forums.

I'll be able to measure the L when I get back to my work place in one week. The coil can not be disassembled, so the circuit has to work with it as is.
Cheers,
Martin

[bernte_one]

you must be under 25years or younger
where did you come from doesnt mean where do you live in the virtual networld
it means whre is you hometown

[mr.sneezy]

you must be under 25years or younger
where did you come from doesnt mean where do you live in the virtual networld
it means whre is you hometown

LOL, an accidental compliment, I'm MUCH older than that

I'm from Adelaide Australia.

I put up a thread for the TX-2002 BTW. I'll tinker with it a bit before giving up to a conversion of some type.

[Teemo]

Pinpointer pictures

Hello everybody!

I'll post some pictures of my pinpointer. (Got the inspiration to make one from the video Juha made about making pinpointer with my circuit:
https://www.youtube.com/watch?v=nS4GWuD5Dk8. I did not have exact same tubes so I used what I found laying around and came up with little different.
Fortunately I found plastic water tubes of 4 sizes that fit perfectly tight inside one another and a plug to close the other end.
The 4xAAA battery holder and the circuit board fits nicely inside the tube. Only had to mount the C2 electrolytic capasitor to the other side of the PCB, and bend the leads of the MOSFET a little. Used coil with ferrite core. Speaker is piezo glued inside the cap with hot glue.
Basically quite durable and easy to make waterproof, only the button is weak spot at the moment. Also I have not closed the coil end with the heatshrink jet, to make it easier to experiment with the coil.
So here are the pictures. Hope you like it.

[Tim]

Hi Teemo. Good recycling there, and a nifty little circuit.
Personally I come to this site to glean simple(to you lot) information, in my quest for a sensitive, simple detector. That, to me, means zero, few, or easily substituted ic's. Preferably an all transistor design. Something that does not result in the homebuilders plethora of mistakes, as indicated by the many questions clogging this site.
To me, the point of making a metal detector is not to achieve a thinking machine, rather to simply give the most comprehensive signal to the ultimate processor, the human brain. A beep design I consider too basic for relics or gold. It should be able to be built on a printed board, or with wood, screws and cup washers, and need no manufacturers service-ever. Cosmetics are secondary, followed by bells and whistles. Battery changing/charging can be eliminated altogether by using 3x18650s, a li-ion charge board and 1w solar panel mounted on the shaft, then regulated to the desired supply.
The sensitivity you describe seems comparable to the 555 circuits online, however these commonly are squared wave BFOs(?), giving a variable sound.
So I see the 2 barriers you need to overcome is sensitivity, and monotone. The sensitivity is where I concentrate with my design, and avoiding generic beeps. Correct me if I'm wrong, but an "air" filter, is that just a radio wave receiver? And de-coupling is done this way, or with diodes, depending on the circuit??
I may not know the lingo, but that hasn't stopped me achieving great sensitivity and a powerful signal.
After all, that is ultimately the goal, isn't it?

[liudengyuan]

[Spyke]

Biuld this detector as pinpointer and it works perfect, I can detect 1 Euro in 7cm.
For me it works best with 470mH coil, wound with 0.2mm copper wire araound a 10mm feritte. The feritte should be longer than coil itself, for me 80mm ist perfect.
I got best detection with mode2 gradual beeping(distance indication). If the device would startup in this mode, this will be fine.
Maybe somebody can change code for me or point me how to do. I already asked Teemo, but he´s not able to do it at the moment, but he told me it wouldn´t be a big thing to do that.

[nick holas]

hi all
hi teemo
could you have look at my pcb and the mod i ve made about the IRL630?(pin 2 pic)
(i just want to aviod using this because it is a little bit expensive)
i saw this trick on an arduino uno output pinout so why not???
thanks

[LOONEY2008]

Hello all, this is my first post so thanks for letting me join, as a first project i saw this as ideal, just a quick question on the parts for the 47nf 400v or 630v better aqnd 5% or 20% version? cheers i found to the best i can some alternatives for the mofset that meet the requirements but also before i go ahead and purchase does a higher amp matter as long as vgs and below 5 volts operation ect meets requirements, and has anyone actually tested as a metal detector not a pin pointer as i cannot see any replies for depth as a coil not a pinpointer,
as this is my first post i would like to thank teemo for his work on this as it was his post on his website that directed me to this forum. thankyou to anyone that can help my questions.

[AndyMuller]

Hello Folks,

I have downloaded the attached file, after UnZip the file, the extension (*.lay6) is unknown for me.
May I ask what software can open this kind of files? or perhaps a photo (JPEG) of diagram

Regards,

Andy

hi all
hi teemo
could you have look at my pcb and the mod i ve made about the IRL630?(pin 2 pic)
(i just want to aviod using this because it is a little bit expensive)
i saw this trick on an arduino uno output pinout so why not???
thanks

[kt315]

this is in Sprint-Layout 6.0. a primitive cad soft for especcially lazy dummies.
take it on a torrent.

[chemelec]

Hello Folks,

I have downloaded the attached file, after UnZip the file, the extension (*.lay6) is unknown for me.
May I ask what software can open this kind of files? or perhaps a photo (JPEG) of diagram

Regards,

Andy

Here is the Picture.

[fekemil]

I was looking for a simple pinpointer here and found this. The one sided circuit was easy to make though I could not get WIMA capacitor. I used another type (Arcotronics) instead. The coil is ferrite core inductor, 470uH, 1.2A.


Programming the pic was difficult for me. I got a KIT150 type programmer, but it does not fully support the 12F1840 pic. I had many unsuccessful attempts, I managed to program the hex and verify it, but the circuit did not work. I think I'm not set the fuses properly. It turns out that there has been no support for this programmer for many years, so I bought a PICKIT3 programmer. PICKIT 3 already supports 12F1840, but in the MPLAB IPE only the low voltage version, PIC12LF1840 can be selected. After the warning was accepted, programming was successful and the circuit works. It can detect 1€ in 1 inch. I'm going to try Spyke's recommended coil either. For me, it has a pretty funny voice