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.
Step 1: 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
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
Check out the video for a live demo of what you can hear.
[Sorry about how dark it is, light receptor on my camera's burned out].