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Portable EMF Reader

Picture of Portable EMF Reader
Want a quick and easy EMF reader? All you need is an amplifier and a microphone. The mic will pick up the electromagnetic noise from around you and the amplifier will turn it into something audible.
Obviously this isn't a precise way of measuring, but if you're lacking a gauss meter, or just want to cheaply investigate the EMF in your home, this is a fun solution.
 
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Step 1: Putting it Together

Picture of Putting it Together
I used a suction cup telephone mic [generally used to record telephone calls] and a battery powered  mini amp I picked up from Radio Shack.

Plug the mic into the input jack of the amp.

Step 2: Using it

Picture of Using it
Turn the volume of the amp to about halfway. If you're not in a Faraday cage, you'll hear a low level buzz. This is the 60 hz background noise that's typical in city dwellings.

Step 3: Example

Position the mic over the EMF source you'd like to listen to [a PC is pretty interesting] and you'll hear the feedback change.

Check out the video for a live demo of what you can hear.
http://www.youtube.com/watch?v=---uCklQU9w
Flash Animation

[Sorry about how dark it is, light receptor on my camera's burned out].
Hmmmm good idea. Have to try it.
pyrohaz3 years ago
Hmm... I don't see how this picks up EMF :S Normally, EMF induces voltage within a coil, I suppose if its a dynamic mic? Cool thinking though :)
vigerpersinger (author)  pyrohaz3 years ago
The sensor (in the suction cup unit) attached to the audio-amplifier is a small coil.
does the amp need a power source?
vigerpersinger (author)  hipydude20013 years ago
Nope, the one in the demo is battery powered.
RedMeanie3 years ago
Another readily available thing you can use > Just use a portable hand held radio or walk-man on AM tuned between stations or to a station. It will detect ANY Electromagnetic Anomaly>>>>
vigerpersinger (author)  RedMeanie3 years ago
Just tried this out with my hand-crank emergency radio. Definitely picked up some interference when the antennae is pointed at an EMF source, but the mic makes it much clearer. When rested against the PC you can hear modulation from the HDD- with the radio, it was much more subtle.
b4polaris3 years ago
we used to use those in the phone company, use a coil on the end of the cable and a signal generator to find metal on metal contact that shouldn't be there. Very good and simple.
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