EMF Detector made easy?
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EMF Detector made easy?
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Bryan
Guest
Posted: Fri Mar 18, 2005 1:21 am    Post subject: EMF Detector made easy? Reply with quote
Hello one and all.

I have been looking into building a "very" sensitive EMF detector due to
issues with power lines in the area. I am sorry to say that I have no REAL
idea on how to do it.
I was also told that there is a way to build a device that would use Hall
effect sensors to measure the earths magnetic field. It would be much more
sensitive and would work if adjustable. I have yet to find a circuit design
that will give a visual as well as audible measurement. An LED bar graph
would be ok.
Any good ideas on what I could build that would do this?

Thanks for your help.

Bryan

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Larry Brasfield
Guest
Posted: Fri Mar 18, 2005 1:43 am    Post subject: Re: EMF Detector made easy? Reply with quote
"Bryan" <abel6479@cox.net> wrote in message
news:eNk_d.14802$Fy.5619@okepread04...
Quote:
Hello one and all.
Greetings, one.


Quote:
I have been looking into building a "very" sensitive EMF detector due to
issues with power lines in the area. I am sorry to say that I have no REAL
idea on how to do it.

Then perhaps you have no real idea of the
potential hazard, and rely on the morass
of conflicting, often misconceived studies
as the basis for deciding there is an issue.

Quote:
I was also told that there is a way to build a device that would use Hall
effect sensors to measure the earths magnetic field. It would be much more
sensitive and would work if adjustable. I have yet to find a circuit design
that will give a visual as well as audible measurement. An LED bar graph
would be ok.
Any good ideas on what I could build that would do this?

If I wanted to do that, I would probably use a
simple coil pickup, followed by a high gain semi-
narrowband 60 Hz filter in front of a PIC's or uP's
A/D input, then implement a much narrower filter
using DSP to pull what is likely to a small signal
out of the noise.

It would be easy to create any display you like
using software and one pin per LED or even
multiplex LEDs to drive more of them. For,
example, at 1 nanoTesla, the red light could
blink gently. At 1 microTesla, the bar would
be fully on and blinking omenously. At higher
levels, you could spell out "Run for you life!",

Quote:
Thanks for your help.
You are welcome.


--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
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Rich Grise
Guest
Posted: Fri Mar 18, 2005 3:05 am    Post subject: Re: EMF Detector made easy? Reply with quote
On Thu, 17 Mar 2005 12:21:45 -0700, Bryan wrote:

Quote:
Hello one and all.

I have been looking into building a "very" sensitive EMF detector due to
issues with power lines in the area. I am sorry to say that I have no REAL
idea on how to do it.
I was also told that there is a way to build a device that would use Hall
effect sensors to measure the earths magnetic field. It would be much more
sensitive and would work if adjustable. I have yet to find a circuit design
that will give a visual as well as audible measurement. An LED bar graph
would be ok.
Any good ideas on what I could build that would do this?

Thanks for your help.


I'd say that if they're too low to detect except with specialized ultra-
high sensitivity equipment, you're blowing smoke up your own ass.

Cheers!
Rich

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Larry Brasfield
Guest
Posted: Fri Mar 18, 2005 3:18 am    Post subject: Re: EMF Detector made easy? Reply with quote
"Larry Brasfield" <donotspam_larry_brasfield@hotmail.com> wrote
in message news:65l_d.31$zO.1051@news.uswest.net...
Quote:
"Bryan" <abel6479@cox.net> wrote in message
news:eNk_d.14802$Fy.5619@okepread04...
I have been looking into building a "very" sensitive EMF detector due to
issues with power lines in the area. I am sorry to say that I have no REAL
idea on how to do it.
[System approach using uP cut.]
It would be easy to create any display you like
using software and one pin per LED or even
multiplex LEDs to drive more of them. For,
example, at 1 nanoTesla, the red light could
blink gently. At 1 microTesla, the bar would
be fully on and blinking omenously. At higher
levels, you could spell out "Run for you life!",

Just to help promote this approach ahead of
the other (as yet unseen) contenders ...

With a little extra complexity in the coil and a
few switches, it could also provide an arrow to
indicate which direction the irradiated user ought
to run. Otherwise, given the usual arrangements
in the vicinity of power lines, he might run without
gaining any *real* benefit from the effort.

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
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Bryan
Guest
Posted: Fri Mar 18, 2005 3:35 am    Post subject: Re: EMF Detector made easy? Reply with quote
Gosh Rich, thanks for the insight!
What a pal!
"Rich Grise" <richgrise@example.net> wrote in message
news:pan.2005.03.17.21.06.28.854635@example.net...
Quote:
On Thu, 17 Mar 2005 12:21:45 -0700, Bryan wrote:

Hello one and all.

I have been looking into building a "very" sensitive EMF detector due to
issues with power lines in the area. I am sorry to say that I have no
REAL
idea on how to do it.
I was also told that there is a way to build a device that would use
Hall
effect sensors to measure the earths magnetic field. It would be much
more
sensitive and would work if adjustable. I have yet to find a circuit
design
that will give a visual as well as audible measurement. An LED bar graph
would be ok.
Any good ideas on what I could build that would do this?

Thanks for your help.


I'd say that if they're too low to detect except with specialized ultra-
high sensitivity equipment, you're blowing smoke up your own ass.

Cheers!
Rich

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Robert Scott
Guest
Posted: Fri Mar 18, 2005 4:19 am    Post subject: Re: EMF Detector made easy? Reply with quote
Someone wrote:

Quote:
Hello one and all.

I have been looking into building a "very" sensitive EMF detector due to
issues with power lines in the area. I am sorry to say that I have no
REAL
idea on how to do it.
I was also told that there is a way to build a device that would use
Hall
effect sensors to measure the earths magnetic field...

Google "Fluxgate magnetic"


-Robert Scott
Ypsilanti, Michigan
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Watson A.Name - \"Watt Su
Guest
Posted: Fri Mar 18, 2005 4:59 am    Post subject: Re: EMF Detector made easy? Reply with quote
"Bryan" <abel6479@cox.net> wrote in message
news:eNk_d.14802$Fy.5619@okepread04...
Quote:
Hello one and all.

I have been looking into building a "very" sensitive EMF detector due
to
issues with power lines in the area. I am sorry to say that I have no
REAL
idea on how to do it.
I was also told that there is a way to build a device that would use
Hall
effect sensors to measure the earths magnetic field. It would be much
more
sensitive and would work if adjustable. I have yet to find a circuit
design
that will give a visual as well as audible measurement. An LED bar
graph
would be ok.
Any good ideas on what I could build that would do this?

Thanks for your help.
Bryan

It's not difficult to build, you an use a ferrite loopstick with a lot
of fine wire wound on it as the sensing probe. One of these is here.
http://www.zen22142.zen.co.uk/Circuits/Misc/emf.htm

Here's a meter using Hall effect sensors.
http://my.execpc.com/~rhoadley/magmeter.htm
http://my.execpc.com/~rhoadley/magmetr1.htm

The big difficulty is calibrating it to a known standard. And they are
not that expensive so there is no point in building one yourself.
There are several companies that offer a calibrated EMF measurement
meter for under a hundred dollars. Here's one with LEDs for under $25.
Also the cellsensor mentioned below. http://www.lessemf.com/gauss.html
Here's their main page
http://www.lessemf.com/

Two other inexpensive meters mentioned in a paragraph from a story found
with google:
"I brought an am radio to the office and it would be very noisy in that
office but not in the other rooms and really bad near the wall and
ceiling. I then went out and bought an emf meter (cellsensor, analog
meter, single axis, $42.00) and measured very high readings only in that
office and the hallway. It would blink and beep like crazy even on the
high setting. I did much research and talked to other engineer friends
who tell me it is unconceivable to have that much emf. So I bought a
digital emf meter (A.W. Sperry EMF-200A, single axis, $60.00) and proved
it. I was getting over 199 mg at the wall about 2" from the conduit
behind sheetrock. It went off the scale about an inch from the wall."
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Rich Grise
Guest
Posted: Fri Mar 18, 2005 6:10 am    Post subject: Re: EMF Detector made easy? Reply with quote
On Thu, 17 Mar 2005 18:29:43 -0700, Bryan wrote:
Quote:
"Luhan Monat" <x@y.z> wrote in message
Rich Grise wrote:
On Thu, 17 Mar 2005 12:21:45 -0700, Bryan wrote:

I have been looking into building a "very" sensitive EMF detector due
to issues with power lines in the area. I am sorry to say that I have
no
REAL
idea on how to do it.
....
I'd say that if they're too low to detect except with specialized
ultra- high sensitivity equipment, you're blowing smoke up your own
ass.

I think I know how I am going to work this now. Thanks to everyone for
their help. Well, almost everyone. For Rich I guess just a peice of
advice.... Rich we all know that liquids conduct electricity. So, be
carfulful next time you are around power supplies, and don't forget to
wipe your chin! He will understand if he really cares.

Well, an aluminum foil hat would be the cheapest solution.

What "issues" do you have with power lines in the area? How sensitive
does this detector have to be? I still say, if you can't detect something
it's probably not worth worrying about very much.

Thanks,
Rich
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Bryan
Guest
Posted: Fri Mar 18, 2005 6:10 am    Post subject: Re: EMF Detector made easy? Reply with quote
"Luhan Monat" <x@y.z> wrote in message
news:yUo_d.6252$uk7.5701@fed1read01...
Quote:
Rich Grise wrote:
On Thu, 17 Mar 2005 12:21:45 -0700, Bryan wrote:


Hello one and all.

I have been looking into building a "very" sensitive EMF detector due to
issues with power lines in the area. I am sorry to say that I have no
REAL
idea on how to do it.
I was also told that there is a way to build a device that would use
Hall
effect sensors to measure the earths magnetic field. It would be much
more
sensitive and would work if adjustable. I have yet to find a circuit
design
that will give a visual as well as audible measurement. An LED bar graph
would be ok.
Any good ideas on what I could build that would do this?

Thanks for your help.



I'd say that if they're too low to detect except with specialized ultra-
high sensitivity equipment, you're blowing smoke up your own ass.

Cheers!
Rich



Try Google: +"smoke detector" +anal

I think I know how I am going to work this now.
Thanks to everyone for their help. Well, almost everyone. For Rich I guess
just a peice of advice.... Rich we all know that liquids conduct
electricity. So, be carfulful next time you are around power supplies, and
don't forget to wipe your chin! He will understand if he really cares.

Cheers!
Back to top
Luhan Monat
Guest
Posted: Fri Mar 18, 2005 6:10 am    Post subject: Re: EMF Detector made easy? Reply with quote
Rich Grise wrote:
Quote:
On Thu, 17 Mar 2005 12:21:45 -0700, Bryan wrote:


Hello one and all.

I have been looking into building a "very" sensitive EMF detector due to
issues with power lines in the area. I am sorry to say that I have no REAL
idea on how to do it.
I was also told that there is a way to build a device that would use Hall
effect sensors to measure the earths magnetic field. It would be much more
sensitive and would work if adjustable. I have yet to find a circuit design
that will give a visual as well as audible measurement. An LED bar graph
would be ok.
Any good ideas on what I could build that would do this?

Thanks for your help.



I'd say that if they're too low to detect except with specialized ultra-
high sensitivity equipment, you're blowing smoke up your own ass.

Cheers!
Rich



Try Google: +"smoke detector" +anal

--
Luhan Monat (luhanis 'at' yahoo 'dot' com)
"The future is not what it used to be..."
http://members.cox.net/berniekm
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Mark
Guest
Posted: Fri Mar 18, 2005 6:10 am    Post subject: Re: EMF Detector made easy? Reply with quote
to start, think about this

do you want to measure the ELECTRIC field at 60 Hz?

or

do you want to measure the MAGNETIC field at 60 Hz?

that is two completly different measurments.

Measuring an electomagnetic field implies you are in the far field
meaning you are many wavelengths away from the source which at 60 Hz is
several miles.

Mark
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John Woodgate
Guest
Posted: Fri Mar 18, 2005 1:19 pm    Post subject: Re: EMF Detector made easy? Reply with quote
I read in sci.electronics.design that Mark <makolber@yahoo.com> wrote
(in <1111109333.304096.190240@f14g2000cwb.googlegroups.com>) about 'EMF
Detector made easy?', on Thu, 17 Mar 2005:
Quote:
to start, think about this

do you want to measure the ELECTRIC field at 60 Hz?

or

do you want to measure the MAGNETIC field at 60 Hz?

that is two completly different measurments.

Absolutely. The OP clearly understands so little about the subject that
advice on making a detector is futile.
Quote:

Measuring an electomagnetic field implies you are in the far field
meaning you are many wavelengths away from the source which at 60 Hz is
several miles.

For 55 Hz, the distance is approximately 1000 km.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
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Frithiof Andreas Jensen
Guest
Posted: Fri Mar 18, 2005 7:29 pm    Post subject: Re: EMF Detector made easy? Reply with quote
"Bryan" <abel6479@cox.net> wrote in message
news:eNk_d.14802$Fy.5619@okepread04...


Quote:
Any good ideas on what I could build that would do this?

A Proton Magnetometer for entertainment/nerd value or a Flux-Gate can
measure the magnetic field component - *what for* and *how to calibrate* is
for the user.

Maybe easiest to buy?

The Electric component can be seen in the dark when holding a flourescent
tube at one end and the other closer to the wires - The 440 kV "SuperGrid"
crossing Didcot, UK will light up the tube a fair bit.

I did the experiment after getting small chocks while carrying a
well-insulated child in a Nylon suit on my shoulders below the wires
whenever child touched my head.

Anyway - Electrometer is the word, I think.
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Rich Grise
Guest
Posted: Fri Mar 18, 2005 10:01 pm    Post subject: Re: EMF Detector made easy? Reply with quote
On Thu, 17 Mar 2005 12:21:45 -0700, Bryan wrote:

Quote:
Hello one and all.

I have been looking into building a "very" sensitive EMF detector due to
issues with power lines in the area. I am sorry to say that I have no REAL
idea on how to do it.

You could check with some of the strawberry growers who are using the
whole corridor under the hi-line alongside I-605. They might know
something about the effects of power line induction.

Good Luck!
Rich
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Watson A.Name - \"Watt Su
Guest
Posted: Fri Mar 18, 2005 11:19 pm    Post subject: Re: EMF Detector made easy? Reply with quote
"Rich Grise" <richgrise@example.net> wrote in message
news:pan.2005.03.18.16.02.04.271952@example.net...
Quote:
On Thu, 17 Mar 2005 12:21:45 -0700, Bryan wrote:

Hello one and all.

I have been looking into building a "very" sensitive EMF detector
due to
issues with power lines in the area. I am sorry to say that I have
no REAL
idea on how to do it.

You could check with some of the strawberry growers who are using the
whole corridor under the hi-line alongside I-605. They might know
something about the effects of power line induction.

Good Luck!
Rich

GASP! You mean those strawberries we eat have been irradiated?!? Don't
let the organic nuts know!

People don't realize how much of an electrostatic field there is around
those high tension lines. But it rapidly dissipates after a few scores
of feet.
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