tangentzero9

I see, so placing it by anything metallic doesn't do anything. (Nor does moving it by anything metallic... to get a changing magnetic field?) Looks like i'll have to make the device a bit more complicated. Perhaps wrapping the string around a hollow tube of plastic (like a straw) and placing a tube magnet in that straw. The magnet can be held in place by springs at either end. Then when an end of the "straw" is placed near something metal the magnet will move...possibly lighting the LED (gotta figure out the current and voltage and possibly AC/DC issues). I guess a voltmeter can help me with that. The greater the magnetic field disturbance the greater the current correct? I understand that in this description above, the LED won't stay lit but only for the amount of time it takes for the magnet to move a bit. It's just a first idea. I'll sit and think about this.

Working on a simple project: I understand that if you wrap a wire into a coil and supply a current through that wire, a magnetic field will be created. What I am trying to do is hook up an LED to a wire which is wrapped around a magnet. Then when the device is placed into the presence of anything metal the current produced will light up the LED. At least, thats what i expected to happen...not even a flicker. Maybe I have my concept of electromagnetism wrong. And if it's right maybe its just not making enough current to light up the LED. Any thoughts or ideas? Using this LED: http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=%2Fspecs%2Fr2_specs.htm I'm using a harddrive magnet like this one :