The use of metal detectors to search for archaeological finds is practiced both by
archaeologists and hobbyists. The metal detector also can use as security. So for this
situation, one device is developing to solve the prob'lem. Metal detector is consists of an
oscillator producing an alternating current that passes through a coil producing an
alternating magnetic field. If a piece of metal, which is electrically conductive, is close
to the coil eddy currents will be induced in the metal, and this produces an alternating
magnetic field of its own. If another coil is used to measure the magnetic field (acting as
a magnetometer) the change in the magnetic field due to the metallic object can be
detected. This project is developed to detect metal like iron, coins that lost. This project
is based on super heterodyning principle which used the principle of heterodyning
(combining two frequencies to create new signals equal to the sum and difference of the
original pair).This signal is transmitted to speaker by filter and amplifier.