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Make a magnetic field detector ? Answered

I dearly want to make a device to measure electromagnetic fields in the house ,since the presence of such has been more than obvious and at times annoying .
My CRT monitors behave strange in my room . The geometry of one bends as i turn the monitor in one direction and at the same direction ,my spare one changes color to blueish like pale . Interestingly, they do it in the same direction no mater where i put them in the room .
My turntable's (i am in to Hi-Fi gear ) cartridge reacts when i put it in some places in the room and i hear noise come out of the speakers until i reposition the turntable .
Anyone have any ideas how i can locate the source ? Some simple device ,or schematic that will give me the ability to measure ,or at least detect to some degree the fields responsible ?
Will be thankful for any answer .



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AndyGadget (author)2011-09-21

 
CRT monitors will slowly become polarised if they're in one place for ages due to the Earth's magnetic field.  As you say, you see the effect when you turn them.
Go to the setup screen and use the 'degauss' function - usually a picture of a magnet.  The screen will shudder as a large AC current flows around the degauss coil.  Do this a couple of times and the colour differences should go.

As for your original problem, a hall effect sensor would allow you to detect magnetic fields.  There's one HERE, although it's not all that sensitive.  If you look at the hall-effect device itself, you could just apply 5V to it and measure the output with a voltmeter for more sensitivity.  No field would be half the battery voltage on that type.  However, this wouldn't help if you had a rapidly reversing field (e.g. from a mains transformer.)

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lemonie (author)2011-09-21


How close to the speakers are the monitors?
Magnetic fields usually to that to CRTs.

L

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Kiteman (author)lemonie2011-09-21

So do MRI scanners and particle accelerators.

Maybe he lives near a hospital or university?

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soundsmyth (author)Kiteman2011-09-21

Odd enough i have no such things close to where i live .The only thing that i know of is a GSM antenna that is like 180 meters away from my window as i calculate it .
Its on another building ,but such field is illogical to come from this device .

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soundsmyth (author)lemonie2011-09-21

They are not close at all . They are like 2.00 meters away .

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