FoxyPI - Arduino Nano metal detector

The electronic unit (in a new housing) and battery compartment are ready for installation and are awaiting the new season :-)

In anticipation of the new season, the electronic unit of metal detector FoxyPI received a new case made of 1.5 mm thick cardboard. The case pattern fits on an A3 sheet.

Harmonica reed plate found in our garden using my homemade Arduino Nano-based metal detector FoxyPI. Most likely, it was lost by a German or Italian (in our area there was a collection center for Italian units after Stalingrad) soldier during WWII.

Detection ranges:

coin 3 kopecks USSR 1979 - 23-24 centimeters,
hard disk platter - 34-36 centimeters
Description (in russian) - https://acdc.foxylab.com/node/47

Over the years of operation, the plastic box of the electronic unit has become unusable, and the installation there was chaotic, since I upgraded the circuit on the fly without reassembling it, and far from every wire I could explain what it connects :)
I rebuilt FoxyPI in a cardboard box.
Reliability was tested by an unintentional fall from a meter height - the latch jumped off the tube, it remained in my hand, and the electronic unit with the power supply was accelerated by gravity :-)

Fresh "trophy" with FoxyPI - forged archaic artifact (before and after cathodic cleaning):

Check "omnivities" MD to coils - a coil from the demagnetization loop (from old TV) (it works well, although the sensitivity is reduced):

A working metal detector, even at a distance of 6 meters, completely suppresses my VLF radio receiver:

This is how the noise from an LCD TV located near the coil looks in test mode: