If you don’t get the results we got, here are some options to check out:Check that all the batteries are fresh, tightly inserted in the battery
pack, and all face the right direction.
Check that no wires or components have come loose.Compare your breadboard against the photos to make sure all the wires
and components are connected correctly.Taking It Further...........................................................................................
Aren’t metal detectors just the most addictive thing? (Well, maybe not, but
they are kind of fun to play around with.) Here are some other things you can
do to have fun with detectors:Have your detector activate a buzzer instead of an LED by simply
replacing the LED in the circuit with a buzzer.Make a more powerful detector that could find coins a few inches
under the sand on the beach.
Check online for other metal detector circuits that have more oomph.
http://www.thunting.comspecializes in metal detectors you can use for
hunting treasure, for example.300 Part IV: Good Vibrations