Can pinpointer detecting thin chain?

[selim]

very nice congratulations.

[walkman]

I finished my pinpointer.
Thanks nupi and chemelec friends.

This schematic used.

https://www.geotech1.com/forums/attachment.php?attachmentid=39670&d=1493827365

https://www.youtube.com/watch?v=7uK7uc2OAmg

[6666]

I left this project unfinished. In the meantime I discovered that this detector can be considerably more sensitive if oscillator voltage is rectified and as such used for detecting, but so far I left it unfinished.

Any new progress ?

[MartyJ1963]

Hiya Tomas,,,I think I'll have a go at making this,,,sounds great on your video,,,what are the values of the 2 potentiometers please? Thanks,,Regards,,Marty.

[Hyena]

Alive

Coil winded on small 8x30mm ferrite rod from ali. ~700uH and ~2,5mH. I use drill for winding these coils, hold ferrite on few mm and wind tightly to end and back. Second coil is twice the same process, so in the end there are 6 layers of 0,3mm wire.

Sensitivity drift over time, but slowly and for me its absolutely usable. Maybe coarse potentiometer could be trimmer or just a pot on board. I drawn board in SMD except elyts and few caps (I only added bypass cap for 4024 and omit 22uF cap for buzzer, also changed 78l05 to asm1117-5 with drop voltage 1V to be able using 2 lithium batteries). I etched it by myself so I made just contact pads to avoid unnecessary drilling. I do not have MKP, stable enough for me... Size without potentiometers is only 45x20x10mm! Able to detect coin up to 5cm. Sucks from 2mA while silent up to 60mA while screaming.

https://www.youtube.com/watch?v=fc6xrj_RaqM&feature=youtu.be

[viwaldi]

Hi viwaldi.
How do you build the coil? of the modified chemelec pp?
Thank you

hi
this is the original nupi project. coil on ferrite from anti-seizing filter (http://www.geotech1.com/forums/attac...4&d=1536131823). I also did chemlet versions with such a coil and also work with coil parameters by using lcr meter t4 -> https://www.youtube.com/watch?v=pHmS83P-z-A

[Marce025]

I have finished my pinpointer nupi , I just need to design the 3d printer for the housing.

[Marce025]

Hi viwaldi.
How do you build the coil? of the modified chemelec pp?
Thank you

[viwaldi]

hi polymer
I had a similar situation - stirring the pinpointer under pressure. it was a ferrite wine. I bought ferrites from old radio antennas. the coil's housing was thick. she did not bend while searching. it was enough to change the ferrite and the pin started working normally. Wound the coil on OTHER Ferrite and check. you can use ferrite from an anti-seizing filter.

[Polymer]

Update on NUPI pinpointer, may be interesting for someone:

Yep, I just used this pinpointer for 5 weeks while abroad. It was an immense help.

BUT, I would change something which I was not aware of before.

I would NOT pot the search head (ferrite and wire) in epoxy again.

Why not?

Even light pressure when poking the pinpointer in the ground seems to mechanically couple to the ferrite sort of "bending" it & changing the magnetic properties.
This causes it to start beeping. Please note that this only happens when adjusted to very high sensitivity.

A possible solution I am going to try is to make a new coil and bed it in swim noodle foam and then put it in the nylon casing.
I hope this will mechanically decouple it from the outside of the search head more or less.

Cheerio

[viwaldi]

New NUPI. Coil on ferrite from the anti-seize filter. Dimensions: 18 cm x 3.2 cm.

[Davor]

I left this project unfinished. In the meantime I discovered that this detector can be considerably more sensitive if oscillator voltage is rectified and as such used for detecting, but so far I left it unfinished.

[6666]

C7 gets charged via R7, from top to bottom, and when it passes ~2.5V U3c and U3d toggle by means of a syncing circuitry. D3 accelerates discharging for the purpose of repetitive use. This circuit is a timer that switches from stabilising stage to the active stage.

Nupi, this schematic is built in ExpressSCH which is a freeware, and often used here.

Davor or anybody else, can you print the copper tracks to check for correct pad sizes etc and to make your own PCB when useing Express ?????

[chemelec]

yes chemelec, I don't think that is the issue i'm just not seeing the voltages I should be in the places I should, I have changed the regulator I case it was breaking down under load.
but get the same results, I am replacing the reg with a different type later, i'm wondering if the batch I have is knock off lol.
as I said its built on perf board as a lot of stuff I have built over the years, but if I cant get it running i'm going to bite the bullet and make one of the boards posted here, though I loathe etching, ferric chloride makes me ill, which is why I use perf board, maybe just starting again is a better strategy.

Use one part of Hydrochloric Acid to two Parts Hydrogen Peroxide.
Works BETTER Than Ferric Chloride and No Staining.

[Polymer]

yes chemelec, I don't think that is the issue i'm just not seeing the voltages I should be in the places I should, I have changed the regulator I case it was breaking down under load.
but get the same results, I am replacing the reg with a different type later, i'm wondering if the batch I have is knock off lol.
as I said its built on perf board as a lot of stuff I have built over the years, but if I cant get it running i'm going to bite the bullet and make one of the boards posted here, though I loathe etching, ferric chloride makes me ill, which is why I use perf board, maybe just starting again is a better strategy.

Don't worry about the perf board, it works just fine.
Funnily enough the first "quick & dirty" ones I built still work the best.
The "cleaner" ones I built later are not so good

I never got to solve the temperature issue, but am still using them in certain situations.