Arduino metal detector?

[FoxyLab]

Air tests of my metal detector FoxyPI with new search coil:

Detection ranges:
coin 3 kopecks USSR 1979 - 23-24 centimeters,
hard disk platter - 34-36 centimeters

[FoxyLab]

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

[FoxyLab]

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

[FoxyLab]

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

[6666]

Yes, it could be used. But it can be noted that using LM385Z with different voltages gives a lot of flexibility in setting up the circuit.

Ok thanks, I just thought I would ask about it, cheers.

[FoxyLab]

is it possible to do away with the external LM385 reference diode , and use the INTERNAL built-in reference, equal to 1.1 volts on the ATmega328P ?

Yes, it could be used.

[6666]

Interesting finds Foxylab, I was just wondering about the Nano code, I am no expert but is it possible to do away with the external LM385 reference diode , and use the INTERNAL built-in reference, equal to 1.1 volts on the ATmega328P ?

[FoxyLab]

One of the new finds with FoxyPI MD (before and after electrolytic cleaning):

Metal with magnetic properties, the shape is close to a hexagon with a side length of about 8 mm, the edges are uneven, and there is an asymmetrical hole in the middle.

Old handmade "iron" button???

[FoxyLab]

what is the latest revision from the foxy lab pi shematic?

During the development of the third version of the firmware, the shematic has not changed since version 3.1. The only thing I added is a digital voltmeter, but it works by itself and does not interact with the firmware in any way.

[FoxyLab]

looks good

Yes :-) But the reason for the appearance of the initial horizontal section is not clear to me, its level is exactly half of the maximum. It would be necessary to experiment with the ATmega ADC reaction to negative voltage, but laziness :-)))

[bernte_one]

what is the latest revision from the foxy lab pi shematic?

[6666]

Want to make
Minimal Arduino Metal Detector

https://www.instructables.com/Minimal-Arduino-Metal-Detector/

[6666]

Examples of signal curves in test mode:
1 - without a target, 2, 3, 4 - when approaching a massive target:

looks good

[FoxyLab]

Examples of signal curves in test mode:
1 - without a target, 2, 3, 4 - when approaching a massive target:

[FoxyLab]

Minor update ( version 3.8 ) is ready (FoxyPIv3_8.ino.eightanaloginputs.hex):
improved display of signal curves in test mode (through earlier reading of preset settings, including contrast).