Different Types of Metal Detectors

Metal detectors are used by hobbyists to locate underground items.
Metal detectors are devices used to find hidden metallic items. These items range from old coins to gold nuggets and metal trinkets, and they are commonly found at beaches and historic sites. All metal detectors operate by sensing changes in magnetic waves caused by metal. However, some types are more sensitive and expensive than others.

Very Low Frequency
A very low frequency, or VLF, metal detector is the most commonly used type due to its wide range of uses. With a VLF detector, a variety of different metals can be detected. This type of detector operates using two round coils of wire. The coil on the outside is the transmitter. This part emits a low-frequency magnetic field onto the ground. A metal object under the dirt causes this field be reflected. A separate inside coil is the receiver. This second coil amplifies any magnetic reflections causes by a hidden object. If these signal reflections are present, an audio tone is played.

In addition to these two coils, a VLF metal detector includes an electronic circuit used to filter the signal from the receiver. This circuit is essentially a "tuner" that allows the user to ignore certain levels of signal and focus only on the desired range. Because different types of metal reflect different signals, a treasure hunter can "tune out" signals from aluminum and steel and focus on valuables such as gold and silver.

Pulse Induction
The pulse induction, or PI, type of metal detector is a more specialized type of unit most commonly used by treasure hunters searching for items deep under the surface. Large versions of PI detectors are also commonly used at security checkpoints to detect weapons.

A PI detector usually uses only one coil. As with VLF types, a coil sends out a magnetic field into the ground. Any metal underground reflects this signal. Instead of using a separate coil for detection, however, a PI unit quickly switches modes to "listen" for the reflected signal. Using this timed pulse method, the device can discriminate between signals it has sent and stray signals from the surrounding area. This makes PI detectors more accurate but also more expensive.

Beat Frequency Oscillation
A beat frequency oscillation, or BFO, type of metal detector is the most simple and inexpensive design. For this reason, BFO metal detectors are popular with beginners. Like a VLF detector, this type uses two separate wire coils for detection. An oscillator creates a constant signal at a set frequency, which is emitted by one of the coils. The second coil detects the interference of this frequency caused by metal objects, which results in a changing audio tone.

The BFO detector operates similarly to the VLF model but lacks the filtering and fine-tuning ability of the latter design. This makes the BFO detector more prone to mistakes and interference and less able to differentiate between trash and treasure.

By Benjamin Aries

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Benefits of Handheld Metal Detectors

Handheld metal detectors were originally created to be a more cost effective, convenient, and less intrusive method of checking individuals at airports, schools, sporting events, clubs, bars, courtrooms, and other facilities. Considering that the majority of places are security-sensitive, it is imperative that an ample amount of precautionary measures are taken on a daily basis. Handheld metal detectors are not only used for security purposes but they can also be used in construction so that the workers are able to find harmful metal debris that could rip up a saw blade. There are many other benefits associated with handheld metal detectors.

The largest benefit of handheld metal detection is that the necessary tools are simple to use. Much like the Garrett Scanner, when the handheld scanner is turned on, there is a particular pattern that is transmitted from the wand to the ground or the object that is to be inspected. If this signal is interrupted by a metal, the detector then receives an alert so that the security professional will know where the metal object is hidden.

The metal object could be a nail in a timber or a razor blade, knife or gun in the pocket of a suspect or detainee.

Throughout the medicinal industry, more doctors are beginning to take advantage of metal detection as it can prove to be far more beneficial than a generic x-ray. As per a variety of scientific studies, it has shown that metal detectors are just as accurate as a traditional x-ray machine in finding objects that children may have swallowed. Considering that metal detection is radiation-free and the detectors themselves are portable, lightweight, and simple to use, they have proven to be more beneficial, quicker and economical.

Throughout the metal detection industry there are inevitably brands that have proven to be consistent and reliable to a large degree over the competition. The Garrett Scanner and the Garrett Super Wand are two products created by Garrett that have been known to be the handheld metal detectors of choice for Homeland security and law enforcement in the USA and abroad. With the implementation of these unique tools, individuals are able to search the bodies of suspects or visitors in order to determine whether they are carrying any type of metallic weapons or not. These scanners are also known for their immense amount of accuracy considering that they are able to detect even the smallest metal object on a human's person.

With the ample amount of different metal detection products such as handheld metal detectors, finding the appropriate model for your job is fairly simple. Whether you are looking for the perfect tool to inspect individuals entering a nightclub or a school, the options available will allow you to choose for portability or accuracy or long life.


By Harry Gatsch
Article Source: http://EzineArticles.com/?expert=Harry_Gatsch

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Advantages and Disadvantages of Security Metal Detectors

I am sure that there is no person that never passed through a walk through metal detector be it on an airport, mall, shopping center, cinema or similar. Detectors are used for safety precautions, and walking into a safe area, after you passed through a metal detector, can be really overwhelming. Saying this in a few simple words - metal detectors make people feel safe!

The feeling of safety can be created while in an airport, college, office building, or any other area where these detectors are being used. People that are using them can control who enters a specific area and what he/she brings inside it.

There are different types and models of security detectors, but the most commonly used are the hand held models and walk through models. With the help of a hand held detector, security personnel can physically detect if some person carries a metallic object. From the other side, walk through metal detectors are much quicker, and they alert the security personnel of dangerous objects such as knives or weapons.

How metal detectors work is quite simple - they use the principles of electromagnetic induction to detect metallic objects. The detection of a dangerous object is notified with a simple beep alarm sound.

In case you need a metal detector, and still don't know which to choose, here are some advantages of the both mentioned models. First of all, the hand held detectors are more affordable and are able to identify the same way as walk though detectors the presence of metallic objects that are considered to be potentially dangerous. From the other side, walk though models are more convenient and more efficient. Overall, if you cannot make up your mind, it is advised that you opt for both models as this way you will surely maximize the safety in the area that requires safety measures.

Detectors are able to deter potential would-be criminals because this way they will think twice after they realize they have to pass through a detector to gain entrance to some specific area.

As for the disadvantages of using security detectors, they are mostly of privacy concerns. A lot of people can find it uncomfortable passing through a detector when trying to inspect whether they have some potentially dangerous metallic objects. In some cases it is possible that they ask to be manually searched when the rules of the safety allow such actions.

Also, in this advantageous medical era, we can find a lot of medical reasons why some person might have metal on his/hers body. Sometimes, metal devices can be surgically installed inside the person's body which will cause the alarm to be set off each time that person walks through a metal detector. In many cases it is possible for the security personnel to see on their computers that the metal object that caused the alarm is actually a harmless tool and not a weapon.

As already said, metal detectors create electromagnetic fields. This can cause electrical interference to electronic devices that one person might have in its possession. This includes medical devices such as pacemakers. Some metal-detectors can harm pacemakers because they have a very strong electromagnetic field. In this case, such detectors can be fatal for those people, and it is strongly advised that they avoid passing through them.

In many situations, metal detectors can give a false alarm if people are wearing some kind of jewelry, watch, phone, loose change or similar. This can make some people feel embarrassed and can cause panic for no reason. A false alarm caused by detectors can be inconvenient both for the security personnel and person to whom the alarm turned on.

When it comes time to purchasing a metal detector the decision can be a tuff one. Consider this list of metal detectors before you make your purchase.

By Brandon Allred

Article Source: http://EzineArticles.com/7522926

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