Home >> Science & Nature >> Rocks & Minerals

How to Make a Simple Metal Detector

Metal detectors rely on the ability of metal to produce a voltage when it moves through a magnetic field. The metal detector has a coil of electrical wire that produces the magnetic field. When the metal moves into this field, it produces a voltage that disrupts the magnetic field. This disruption creates an electromagnetic signal that the metal detector converts into an audible signal. You can make a simple metal detector from household items.

Things You'll Need

CD case
Ruler
AM radio (pocket-size)
Calculator (solar-powered)
Scissors
Velcro
Tape
Metal object

Instructions

- 1
  Remove the insert inside the CD case. Locate a flat area on the back of the radio and measure its size. Cut out a Velcro piece of the same size. Repeat this procedure for the calculator.
- 2
  Place the Velcro hook piece on the back of the calculator. Attach the other hook piece of Velcro to the back of the radio. Stick the loop pieces of Velcro on the interior sides of the CD case. Attach the radio and calculator to the inside of the CD case by sticking the matching pieces of Velcro together.
- 3
  Turn the radio on and set it to AM mode. Turn the volume up and tune the radio to the highest AM frequency that is not receiving a signal. Turn the calculator on as well.
- 4
  Close the CD case slowly until you can hear a tone from the radio above the static. Slowly open the CD case until you can barely hear the tone. Place several lengths of tape across the partially open CD case to allow you to find this position easily.
- 5
  Move the CD case towards a metal object with the CD case open as far as the tape will allow. You should be able to hear the tone when the CD case gets within a few inches of the metal object.

Rocks & Minerals