PI + Magnet Detector with Super DD Coil

[Detectorist#1]

Hi DIY enthusiasts,
Now, I propose an idea for bipolar PI detector combined with magnet sensor with Super DD coil. The magnet sensor in "Fe" mode is enough sensitive to recognize bottle cap from 20-25cm as sure Fe target. 25cents USA are recognized from 25-30cm and in "ALL" mode is possible to recognize under gram targets. All this is possible ONLY on relatively flat environment with relatively homogenous soil. The benefits of this solution are:
- good EFE suppression
- automatic GB
- no need to use of input OpAmp with extremely low noise at very low frequencies
- no dangerous to activate mines with magnetic activation
- using of standard USB-C home charger
The scheme of this MD is attached.
I'm open to discussing on this solution.

[Detectorist#1]

Hi,
This is my attempt to change the reputation of the PI detectors as non capable to have reliable discrimination Fe/non-Fe for the targets. Not universal solution - but good for small targets in moderate deepness.

[Detectorist#1]

Hi,
Possibility for more fast first delay with Super DD coil variant of the search sensor allows to move the final TX switches from the small sensor board to the main board of the this solution. This allows to be used more simple sensor board consisting only the first receiving amplifier. This seriously reduce the size of this board and simplify the symmetrizing of the bipolar RX signals. The solution of the sensor board PCB is very simple and this allows to be used very small prototyping board for this purpose. My experience with PI detectors with separate TX and RX coils points that not using of first amplifier in small board inside the sensor unit haves as result big influence of the near hands to the connecting cable when delays under 10us are used despite of many tested variants of the cables. Using of the sensor board inside of the searching sensor seriously reduces this problem.
Attached are the schemes of the Main Board and of the project of the Sensor Board PCB for this more simple to be repeated solution.

[Detectorist#1]

Hi,
My next tests will be with a sensor with balanced OO coil for passive recognition of Fe targets. The purpose is to make further reducing of the complexity of the search sensor, more convenient for repeating from DIY people.

[pechkata]

I think you started writing on the forum yourself...