WHAT METAL DETECTOR'S DO
Metal detectors rely on an oscillator that produces an alternating
electrical current. This current passes through a coil of electrical
wire that produces an alternating magnetic field. If an electrically
conductive material (such as most metals) comes close enough to the
coil, it will create a second alternating field which the metal detector
can then analyze. This use of electromagnetic induction can be
demonstrated by building a very simple metal detector with an AM radio
and a calculator.
WHAT YOU WILL NEED
SMALL AM RADIO
SOLAR POWER CALCULATOR
CD CASE
INSTRUCTIONS.
1.Remove the insert of dark plastic from the CD case that keeps the CD in
place. Measure out flat spaces on the backs of the calculator and radio
where you can stick Velcro strips without interfering with their
operation.
2.Cut two hook and loop pieces of Velcro of the size that you measured in
Step 1 and attach the hook pieces to the interior sides of the CD case.
Attach one of the corresponding loop pieces to the back of the radio and
the other loop piece to the back of the calculator in the locations you
selected in Step 1.
3.Mount the radio to one strip of Velcro on the CD case and the calculator
to the other strip on the CD case. Turn the calculator and radio on and
set the radio to AM. Turn the volume up and tune the radio to the
highest frequency that's not receiving a station. You should only be
able to hear static.
4.Fold the CD case until you hear a tone from the radio. This tone is the
radio signal that the calculator is producing. Open the CD case until
you can barely hear the tone.
5.Move the CD case towards a metal object until you hear the loud tone
again. The metal object is creating a secondary magnetic field which the
radio can detect as a steady tone.
I HOPE YOU ENJOYED THIS METHOD AND HOPE YOU AND YOUR FAMILY HAS FUN WITH YOUR HOMEMADE METAL DETECTOR.I BUILD MANY OF THESE AND YOU WOULD BE SUPRIZED OF THE PERFORMANCE AND HOW THEY WORK.
