Metal Detectors -- for Business and Hobbyists
Metal detectors use electromagnetic induction to detect metal. Uses include demining (the detection of land mines), the detection of weapons such as knives and guns, especially at airports, geophysical prospecting, archeology and 'treasure hunting'. Metal detectors are also used to detect foreign bodies in food, and in the construction industry to detect steel reinforcing bars in concrete and pipes and wires buried in walls and floors.
In it's simplest form, a metal detector 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.
Many people use consumer metal detectors to look for coins on the beach. Most metal detectors are only good to detect metal within a foot or so below the ground. The detection depth depends on the type of metal detector, type of metal in the buried object, size of buried object, type of metals in the ground, and other objects in the ground.
There are four major types of hobbyist activities involving metal detectors:
- Coin shooting - looking for coins after an event involving many people, like a baseball game, or simply looking for any old coins
- Prospecting - looking for valuable metal like gold and silver
- Relic hunting - looking for items that are historically significant, like weapons used during a war
- Treasure hunting - looking for items that are rumored to be hidden (Wikipdia)
There many business and hobby uses for metal detectors. Please use the resources on Beyond Metal Detectors to find te best product for your needs.