Metal Detectors

At a basic level, a metal detector is a device that emits an electromagnetic field when activated. This field will then energise any metals that are within its range which in turn emit their own electromagnetic field that is then detected by the device’s receiver.

When searching online, you will notice that the majority of metal detectors are large devices that are used by hobbyists to find metal objects hidden underground. At Interconnective our focus is on security metal detectors.

These will come in two broad categories. You will have the common handheld metal detector which is often called a security wand, metal detector wand or security paddle and the larger walk-through metal detectors.

These terms refer to a specific shape of handheld metal detector that is normally long, flat on one or both sides and has a wide detection area. The flat end is what is used to perform the sweep. As to why they are called wands, this is an old term from years ago that has stuck. Our best guess is that it is because you wave them around like a wand but that is conjecture.

Often called probes, these are a type of handheld metal detector that normally has a detection area that extends in all directions around the probe. In some cases, such as the Garrett SuperWand and the Adams 360, the detection area will also include the tip of the device. This allows the user to cover more ground and search around bends and at angles.

Having the detection area form a circle rather than run along a straight path is another method of constructing handheld metal detectors. This is often used for ultra-sensitivity models such as the ER3000 and the AD2600S but can also be used for standard handhelds like those produced by Rapiscan.

Walkthrough metal detectors are normally large frames that members of the public will walkthrough when entering a venue. They work much in the same way as handhelds and will pick up metal objects as the target passes through the sensors. The most common brands for these are Garrett, Fisher and M-Scope with many companies white labelling their products and reselling it. There are also many Chinese versions of these walk-throughs which come with the same warning as the handhelds from the same country.

All metal detectors use a receiver to pick-up electro magnetic fields. The detection area is the area over which the receiver can receive a signal from energised masses of metal. If a hidden object is outside of the detection area, it may not be picked up. For this reason, wider and longer areas are better but you must consider that by increasing it, you make the device clumsier and more unwieldly. Garrett Superscanners are wider than most but they are less compact than an Adams AD-10/11 range device or a Fisher handheld.

There are three primary alarm types that you will find with handheld metal detectors. Audio, Visual and Vibration. Some models like the Garrett Superscanner V will include all 3, others like the AD11-2 and AD11-V will offer two, alternating between them. The audio alarms emits a beep when a successful detection occurs. Visual alarms are usually an LED light that shines when a piece of metal has been detected. The vibration alarm is the most discreet option, indicating to the user by way of a buzzing that only they can feel.

Metal detector wands are generally employed by security personal who do a “sweep” of a target. This normally involves moving the wand around the body, only a few centimetres above the surface. Well-made metal detectors do not require physical contact. This process should only take a few seconds and will generally focus on areas of the body where objects can be concealed.

While there is not a best, there are brands that are more recognisable than others. Garret, Adams, Fisher and Rapiscan are all well-known US brands that have a strong reputation in the industry. It is generally recommended that Chinese metal detectors be avoided for a number of reasons.

Chinese metal detectors are largely rip-offs of the Garrett Superscanner. They use low-cost materials which results in unreliable sensitivity and frequent breakdowns. You can buy Chinese made metal detectors very easily on the internet, they are made by only a handful of companies in China. You will notice that the vast majority of them use a very similar shape, will often be called Super Scanners and tend to have the same problems. We also advise strong caution with these as they are largely not reliable enough for use in professional security.

You will often see this mentioned in descriptions for these devices. Ferrous metals are those that contain iron. Non-ferrous metals are any other metals that do not contain iron. For security metal detectors, it is important that they are able to detect both kinds.

Not normally. The vast majority of metal detectors will have a low power draw meaning that it would not need regular recharging even if it could. They tend to use 9V batteries but there is some variation. There are however a few manufacturers like CEIA who have rechargeable models with a special cradle. These tend to be much more expensive than the 9V models.

Water-resistant is relative but the majority of US and UK brands will have an IP rating which denotes ingress resistance. For electronics, the most important factors are moisture and dust particles. Most devices will have an IP65 rising to IP67 at the upper end.

Any manufacturer in Western countries will have to abide by stringent production regulations. These include ensuring that they are safe for use around people with pacemakers and other medical issues. If they do not, they will have to include a notice on the product declaring this. The same restrictions are not applied to brands from many other countries.

To do this you will need an ultra-sensitive metal detector which are normally circular-style devices. Many of these are employed in hospitals and pediatrics units to see if a patient has ingested something that they should not have. Adams produce a range of these at differing sensitivity levels and with different functionality.

Sensitivity can be a difficult subject. If it is too high, there may be too many false positive detections. If it is too low, the device will not pick up the items you are searching for. Handheld metal detectors are employed to find specific objects. Security wand style devices that do not have adjustable sensitivity will get set to pick up large pieces of metal such as blades, guns and offensive weapons. Adjustable sensitivity devices will have a dial or switch that you can use to achieve the level that suits your needs. These require some setting up before they can be deployed.