The voodoo project : Pi coil inductance

[nandimonay3]

Hello George . I hope you will be fine
Finally i made succefuly this project after buying original ICs.
Now ... After reading the book of this project i want to make a coil.
the part information about the coil is more complicated for me . Im not interesting about VLF (DD coil ) .
I want to make PI coil . I asked Mr (surfdetector) about that and he answer me i can use one half of dd coil like pi coil . But i want to know the right inductance compatible with this machine . Because i want to change the size of the coil to detect more deepth. Any help plz

[Qiaozhi]

Hello George . I hope you will be fine
Finally i made succefuly this project after buying original ICs.
Now ... After reading the book of this project i want to make a coil.
the part information about the coil is more complicated for me . Im not interesting about VLF (DD coil ) .
I want to make PI coil . I asked Mr (surfdetector) about that and he answer me i can use one half of dd coil like pi coil . But i want to know the right inductance compatible with this machine . Because i want to change the size of the coil to detect more deepth. Any help plz

As you can see in Table 6-1 on page 75, it is possible to use quite a wide range of coil inductances.
The large concentric coil is probably a good guide for building your own coil, with TX = 347uH and RX = 1.14mH.

[nandimonay3]

Thanks for answering my question
Is it necessary to use concentric coil with two bobines ?
I want to test a coil with 1m?1m .
Just one bobine on the PI mode
Is it possible ?

[Carl-NC]

Yes but you will only get PI results.

[Qiaozhi]

As Carl said ... you will only be able to operate in PI mode, and would therefore lose the advantage of ferrous detection which is the whole purpose of Voodoo.

Also, a 1m coil is not really a practical solution with Voodoo because it's a motion detector. PI detectors with large 1m coils normally use non-motion or a very slow SAT.
Either the Arduino Nano PI or Minipulse Plus would be a better alternative.