Low cost Metal Detector
Posted on Sep 22, 2012 9575
Metal detectors are usually very complicated and it may be consist of very costly components and metal detector DIY circuits are rare. However this metal detector hobby circuit can be constructed by only a few components such as BC548 and an ordinary AM radio that we usually use.
This metal detector schematic shown in the figure oscillates according to the frequency of any tuned AM radio. When the circuit powers up, the radio will not produce any sound because the radio oscillatory and the the metal detector oscillator will be in the same frequency and each will cancel itself. Working We all need to adjust the frequency of electronics circuit of metal detector to the tuned radio frequency. Whenever a metal part come aside the circuit, the cancellation of two signals stops and the radio starts producing sound. Important: Never assemble the circuit in a metal cabinet. Do the circuit on a common PCB and assemble in a plastic cabinet.