Metal Detectors


Metal detectors are popular devices that have many practical applications. They are used for security purposes as well as by hobbyists. A metal detector is defined as an electronic device that is used to detect the presence of metal. They are offered in sweeping models, archway models and handheld waving models. There are several different technologies that can be used to detect metal.

o    The three most popular types of metal detectors are handheld wands, walk-through arches and handheld sweeping metal detectors. Metal detecting wands are most widely used by security personnel. They are lightweight, powerful, easy to carry and portable. Walk-through arch metal detectors are used in airports, government buildings and retail centers. Sweeping metal detectors are mostly used by hobbyists in their leisure time.

o    All metal detectors employ one of a few different technologies to detect metal. “Very low frequency” metal detectors create a magnetic field that reacts with metallic objects in its path. “Pulse induction” metal detectors create magnetic pulses that reverse polarity suddenly resulting in electrical spikes. Pulses take longer to spike when the metal detector is over a metallic object. “Beat-frequency oscillator” metal detectors let off radio waves, when the detector passes over a metallic object, magnetic currents interfere with the radio waves.


o    Beat-frequency oscillator metal detectors are the most affordable metal detector due to their low production costs. Pulse induction metal detectors detect metallic objects that are deeper underground than other metal detectors can sense. Very low frequency metal detectors are unlike other types of metal detectors in that they can tell the difference between metals in the ground below them.


    Walk-through metal detectors usually employ pulse induction technology to detect metals. Beat-frequency oscillation is the technology that is most widely used in handheld security metal detectors. The most popular technology used in metal detectors is the very low frequency technology.

A metal detector is a device which responds to metal that may not be readily apparent.

The simplest form of 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 electrically conductive metal is close to the coil, eddy currents will be induced in the metal, and this produces an alternating magnetic field of its own.

Nowadays, there are metal detectors that can pinpoint metals so accurately that they have become indispensable tools in fields like mineralogy, engineering, security and even in the military.

From the crude models of the 19th century, the modern detectors had its debut in the 1930s when Gerhard Fischer released and patented his very own metal detector. Fischer’s design used resonating coils to detect the presence of metal under the ground. These metal detectors proved to be an asset during World War II.

Metal detectors were used during the war to find land mines scattered across the paths of troops. They saved a number of soldiers back then. However, these metal detectors could have been more useful if they were not that heavy. Early designs of metal detectors were not that convenient as compared today. These detectors require a great amount of “juice” to power up which means lugging behind heavy batteries.

The modern detectors basically are made up of coils and uses electromagnetic induction to detect the presence of metal. Aside from the portable metal detectors that we have grown accustomed to and use in hobbies and games like treasure hunting, there are some bigger models that are used mainly in security and related fields.

Other uses for metal detectors include detection of foreign objects in food. These pieces of equipment are of course very useful in the construction industry as well. You could easily detect steel reinforcing bars, pipes and wires that are buried in walls and floors with a detector.

Powerful metal detectors are also used to determine the location of mineral ores for the mining industry. In the field of archaeology, artifacts can be detected even if they are buried deep underneath sand or soil. During rescue missions, sometimes metal detectors also come in handy. In places like airports, security uses walk in metal detectors to determine if people are carrying metallic objects like knives and guns which can cause potential dangers to passengers or commuters.

The standard coil detectors were the trend back then, but recent technologies have brought about new breeds of metal detectors. You can now see the Beat Balance and Coil Coupled Operation metal detectors which were made available to the public just a couple of years ago.

Most machines are operated using microchips. This can be seen when opening the hood of the car and looking at the control box, the remote control of the television and the interior of the microwave oven. These little things can be programmed to do whatever the person wants in a matter of seconds, which is something everyone needs living the digital age.

Metal detectors also operate using the same concept. Though this machine has been around for quite some time, advances through the years has made it much better than it was before allowing the person to use it to even detect the smallest metallic object in any terrain.

The kind of chip commonly used by the metal detector is known as the 7400 series logic. These are the tiny pins located in each card that becomes the controls of the machine. Manufactures have to be test this out so that only those who pass quality control will end up in the display shelves and into the hands of the customer.

The control box is powered by one or two 9 volt alkaline batteries. When it is activated, the person can already adjust the settings and start searching for objects buried underneath. Before using the metal detector, it is always best to study the model and be familiar with how to use it. The individual should let it warm up for 30 minutes and then practice using it.

Lately, there have been some improvements with these devices. A better chip known as the 18 pin IC allows the individual to home in on an object up to more than a few inches away from it.

While its true that treasure hunters don’t pay that much attention to this and are only concerned with how well the detector performs, this is something worth knowing should any problem happen. The person will be able to understand what the technician is talking about to know which part will be replaced.


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