Malysh FM

[yo4hfu]

This is a old thread but i have one question about this pinpointer. I build malysh-fm first version (without external oscillator). On the table everything is ok, good stability and sensitivity but outside my pinpointer response like a magnetic compass . It has a high sensitivity regarding magnetic field of Earth. Is very easy to identify the N-S direction.
The coil use 5cm of ferrite core from AM radio. Inductance is 1,25mH and i have same results with/without static shield.
Has anyone noticed this problem?

[Toros]

This is a old thread but i have one question about this pinpointer. I build malysh-fm first version (without external oscillator). On the table everything is ok, good stability and sensitivity but outside my pinpointer response like a magnetic compass . It has a high sensitivity regarding magnetic field of Earth. Is very easy to identify the N-S direction.
The coil use 5cm of ferrite core from AM radio. Inductance is 1,25mH and i have same results with/without static shield.
Has anyone noticed this problem?

The main problem with this PP is that the detector must be firm and rigid all the details, including the battery and cables for connecting the battery and antenna. The detector responds to each movement of elements in the box. The author admits that the first version of the software have bugs that he is now corrected. If you read Russian, you can see here:
http://smartelectronix.biz/publ/rabo...katel/1-1-0-75
New software is here:
http://smartelectronix.biz/load/0-0-0-64-20

[yo4hfu]

Thank you Toros, you give me a fast and useful response. I changed the firmware with "MetFM_v2_675.hex" and now the stability is very good, "magnetic compass effect" disappeared.
All the best!

[bernte_one]

hello yo4hfu

is the coil inductivity correct? as i remind the versiond i build has around 2250µH

[Eddy71]

Look for my new version of "MalishFM"

http://smartelectronix.biz/publ/rabo...katel/1-1-0-75

and "MalishFM v2"

http://smartelectronix.biz/publ/pros...bkami/1-1-0-74

Fast start and greater stability.

[yo4hfu]

In this morning i made a new test with PP (version without external oscillator & last firmware). Again the same problem of instability was appeared...Is not a mechanical instability. Everything is good in fixed position but when i go outside in my garden and i make a new self calibration, the PP is stable only if i hold same azimuth.
PP is stable if i hold this first position and i walk around. If i rotate slowly left/right, the PP response with metal/nonmetal signal. Is exactly like a magnetic compass. The frequency is shifted by earth magnetic field, i don't have other explication...

My coil has 1,25mH, this value is from original schematic. Self calibration procedure is passing without error, this mean a good frequency of the oscillator. Frequency is 18,75KHz.

I my area i don't have perturbations from high power VLF-LF transmitters or other radio sources.

[Eddy71]

This schematic not work with ferrite rod, only with simple coil. You make magnethometer.

[bernte_one]

BIG thanks to Eddy71

whish you all the best, not easy time in lugansk

[Eddy71]

Thank you, everything will be fine, I'm sure.

[yo4hfu]

This schematic not work with ferrite rod, only with simple coil. You make magnethometer.

Thank you Eddy71 for advice, this was the problem. Now i use one coil without ferrite core and PP is stable. The new firmware is very fast and has a good stability.

Here is my next pinpointer: . I added a step-up dc convertor 3,7/5V (LT1302) and a low battery monitor (TL431).
"Malysh-FM" is a good project. All the best!

[greylourie]

Bosch Pinpointer !

[yo4hfu]

BOSCH PP ready for weekend hunting

[Qiaozhi]

BOSCH PP ready for weekend hunting [ATTACH]33401[/ATTACH][ATTACH]33402[/ATTACH]

Ingenious!

[Fabian]

BOSCH PP ready for weekend hunting [ATTACH]33401[/ATTACH][ATTACH]33402[/ATTACH]

"Chinese" Nupi PP

[Davor]

Now that Malysh popped up elsewhere on Geotech, I wonder if there is a source code for it so that it may be ported to, say, Arduino?
I guess it is a pulse counting FM.