Can pinpointer detecting thin chain?

[Marce025]

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

[Marce025]

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

[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

[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=fc6x...ature=youtu.be

[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.

[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 ?

[walkman]

I finished my pinpointer.
Thanks nupi and chemelec friends.

This schematic used.
https://www.geotech1.com/forums/atta...0&d=1493827365


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

[selim]

very nice congratulations.

[Eddy71]

And when the rod rotates in space, isn't there an erroneous detector response?
(rod looks long)

[dbanner]

Northfinder pinpointer pro.

[walkman]

And when the rod rotates in space, isn't there an erroneous detector response?
(rod looks long)

Hi Eddy71,

I haven't seen such an error yet. I will continue the tests.

Ferrite rods 1cm diameter and 70mm long. L1=1,6mh L2=0,330uh

5,5 cm under the brick 1 coin detect.

[Eddy71]

A long rod works well on a table if it is not moved in space.
I've seen errors when the rod moves up and down, right and left. The magnetic field of the earth has a strong effect on the long rod.

[Carl-NC]

In the F-Pulse/TekPoint I used a 9x65mm ferrite rod, or something like that. With bipolar pulsing to cancel Earth field there is no compass effect at all. Probably will get similar results with monopolar pulsing and an EFE subtraction sample.

[Andi68]

Bipolar Pulsing??

[Carl-NC]

Bipolar Pulsing??

Current pulsed in both directions, using an H-bridge drive.