Elektor 5/07 Magnetometer

[rael]

Simple Magnetometer project found at follow link:

http://www.elektor-electronics.co.uk/Default.aspx?tabid=27&art=53325&PN=On

Using 220V/12V mains transformer for sensor.

[Esteban]

Andy Flind's project on EPE (January 1995) is based also on transformer. Signal shows via 10 leds and audio variation. Uses common chips. You can modificate it for various purposes.

[okantex]

Hi Both of them looks easy .
but I can not get image bigger and clear.
so can not see components.
can not you give larger resolution pics.

[rael]

Hi okantex,

Carl Say:
'Don't post copyrighted material'
http://thunting.com/geotech/forums/s...ad.php?t=10526

Larger resolution pics found at:
http://www.elektor-electronics.co.uk...rt=53325&PN=On

[okantex]

hi Rael

did you build this magnometer?

do leds shhow increase and decrease of filed strength.in other words for positive and negative fields.

[asguard]

This one might be even easier for you.

http://www.ssec.honeywell.com/magnetic/applications/gradiometer.html

Regards
asguard

[rael]

Hi okantex,
Not, I never try this. I think Gradiometer is better, if You have HMC1021S sensors.


BRGDS

[asguard]

Hi okantex,
Not, I never try this. I think Gradiometer is better, if You have HMC1021S sensors.


BRGDS

You can use the HMC1001 magnetoresistive sensors too, instead of the HMC1021S`s . And even the KMZ ones.

If you want to experiment you could salvage the magnetic sensors out of an old disk drive, (most have 3, they`re even smaller than the 1001`s, bout the size of a match head....lots of fun to solder without small tip and fingernails, even more difficult to align).

All the best

[okantex]

why do you think gradiometer is better than this.

[Crowbar]

Gradiometer and induction magnetometer are different things.

[Steve in MS]

On the subject of Gradiometers, exactly what are they good at doing? Is there some info on them somewhere to read?

[rael]

Hi,

More about magnetometers and gradiometers You can find at Geotech's Magnetometer Projects and Magnetometer References pages.

http://geotech.thunting.com/cgi-bin/pages/common/index.pl?page=mag&file=info/sensors/index.dat

http://geotech.thunting.com/cgi-bin/pages/common/index.pl?page=mag&file=/projects/fmx1/index.dat

"Gradiometers.
One of the problems with magnetometers is that small fluctuations occur in otherwise very large magnetic fields,
and those fluctuations can sometimes be important. A further problem with singlesensor systems is that they are very
sensitive to orientation. Even a small amount of rotation can cause unacceptably large, but spurious, output changes.
The changes are real, but are not the fluctuations that you are seeking. A gradiometer is a magnetic instrument
that uses two identical sensors that are aligned with each other so as to produce a zero output in the presence of a
uniform magnetic field. If one of the sensors comes into contact with some sort of small magnetic anomaly, then it
will upset the balance between sensors, producing an output. The gradiometer gets its name from the fact that it measures
the gradient of the magnetic field over a small distance (typically 1 to 5 feet)."

"Expermenting With Magnetic Sensors" by Joseph J. Carr, part 2 page 3

I think, transformmer sensor have insufficient sensitivity for field research use.

[okantex]

what about the ELF(150kz) reciever project at same magazin?
did any body try it.it looks like EMFAD UG12 in manner.
can not it be used as it if antenna hold like detector ,I mean directly to ground.

[Crowbar]

It's very strange how does an EMFAD searchs in VLF range 44KHz and up without any active transmitter.

[Crowbar]

I mean how it can detect any physical object at normal range without any trasmitter-reciever techniques...