The upper hand

Last updated 1 Apr 13 @ 11:40 |
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High-sensitivity handheld metal detectors are being used in an increasingly diverse range of environments, from airports to prisons and hospitals. Robert Adams reports on the latest technology


The handheld metal detector – also known as the “hand wand”, “transfrisker” or “HHMD”, among other names – is probably one of the most instantly recognisable security devices in use today. Its suitability for many different settings, from the world’s busiest airports and highest-security prisons to high street stores and even local pubs, makes the HHMD a truly portable, easy to use, inexpensive and very effective search enhancement tool. However, with an ever-increasing choice of HHMDs arriving on the market, are all handheld metal detectors created equal? And do they fundamentally all perform to the same level as each other?

The HHMD began life in the late 1960s. In the mid-1970s, more developed versions of the device began to make their first appearances at major airports after a series of hijacking incidents in the Middle East. The HHMD then had a more defined role in the newly emerging business of “airport security”.

Many years on, we have seen steady progress in the field of HHMD development, although most developments have centred around peripheral features on the detector, such as vibration alerts (which are now the industry standard) and various ways of recharging the battery. The aesthetic appearance of the HHMD has also changed a little, with some detectors now made in a nightstick or truncheon shape. Tougher materials and more rugged construction designs have also been employed; many products now have rubber handle grips and various LED indicator lights. One HHMD even boasts an LED flashlight that can be used to illuminate the search area while scanning a person.

Until fairly recently, however, very little had been accomplished in the actual advancement of the metal detector’s electronic sensor technology. A far greater level of performance and sensitivity was required to detect more challenging metal targets than just guns and knives. Objects with a very low metal content, such as SIM cards used in mobile phones or extremely small high-grade surgical steel blades, were virtually undetectable with the standard technology.

One of the more significant steps forward in the field of electronic technology has been in the area of super high-sensitivity metal detection using what is known as continuous wave (CW) technology. This technology enables the detection of very small amounts of metal at a much greater distance than ever before, making it ideal for the detection of objects that could be concealed deep inside clothing or even below the skin quickly, safely and inexpensively. It is ideal for the ever-increasing challenges of today’s modern prison environment, where prison inmates frequently conceal items ranging from handcuff keys, razorblades and drugs wrapped in foil to metal shanks, sharpened hacksaw blades, welding rods and much more. With the addition of the mobile phone and its various component parts, the incarcerated individual can now run criminal business affairs relatively unhindered from their prison cell.

Before super high-sensitivity detectors arrived on the market, the only HHMDs available for these search procedures were the old-style general performance “hand wands” used in airports. These were only really designed to detect much larger and more general items such as handguns and knives, shaped like a large flat paddle and not able to detect or pinpoint an object with any degree of accuracy. The use of such devices in today’s demanding prison environment may serve as a deterrent, but would have little or no effectiveness in the detection of smaller metallic objects and certainly no effectiveness in the detection of mobile phone components and SIM cards.

In today’s constantly challenging prison environment, the new generation of super high-sensitivity HHMDs are increasingly important. They are able to detect ultra-small metal objects inside body cavities, yet are also portable, inexpensive and reliable enough for constant daily use. Prison inmates are finding more ingenious ways of concealing contraband than ever before. In one US prison, for example, a positive reading from the HHMD was detected around the chest and neck area of an inmate. After much closer examination, it was discovered that a piece of razorblade wrapped in electrical tape had been attached to a back molar tooth with dental floss, then swallowed (dangling down the esophagus), to be retrieved later by the inmate. Desperate measures indeed, but these are the real challenges faced by prison guards every day. The detection of mobile phone component parts smuggled inside body cavities is still proving to be one of the biggest challenges. The arrival of the new generation of super high-sensitivity HHMDs gives the prison guard a better chance of detecting and locating objects that were previously passing through security checkpoints unnoticed.

British airports and border control points are also starting to use high-sensitivity HHMDs. One difficult question for airports in the past has been how to screen an individual with loose fitting clothing and still be able to scan between the legs without being intrusive. A high-sensitivity HHMD is able to scan with the added range necessary to be able to search between the legs from the front or the back of a person without being intrusive. As a result, there have been more discoveries of weapons and other prohibited objects strapped to the inner thigh or leg area. These would have remained undetected using the standard low-performance hand wand-type HHMD. With the deployment of these more sensitive HHMD devices in our airports and border control checkpoints, it is possible to add an extra level of security and greater efficiency to the general screening process.

Hospitals and other establishments outside of the security industry are also finding uses for high-sensitivity metal detection technology. The high-sensitivity HHMD’s ability to locate tiny ingested metal objects below the skin tissue without the need for costly x-ray procedures makes it a useful medical tool.

Other new innovations in the field of handheld metal detection have come as adaptations of this technology, such as the “hand-worn” metal detector (HWMD), also known as the “e-glove”. This device is worn on the operator’s hand, rather than held in the hand, and is said to give the operator a “sixth sense” by utilising their sense of touch in conjunction with simultaneous active metal detection. As with all new ideas, the initial response to this device was enthusiastic, if perhaps a little skeptical at first.

That said, the HWMD has since found its place in the security industry as a valid hand search and pat down tool that leaves the operator’s hands free to perform other tasks, eliminating the need to pick up and put down the device between searches. It is particularly useful in poorly lit, noisy and chaotic environments and as a result has become very popular with the police, doormen and prison guards. It is particularly effective for tasks that require good overall performance as well as the ability to detect very small objects.

When the HWMD detects a metal object on a person, it vibrates against the operator’s wrist. It has no flashing indicator lights on it and therefore has an innocuous appearance on the hand, resembling a fingerless glove or support strap. In most cases, the person being searched has no idea they are being patted down by a metal detector. This gives the security guard a definite tactical advantage and enables them to call for assistance in high-threat situations very discreetly and safely.

Another adaptation of the standard HHMD is the “tactical HHMD”. These modern detectors first made an appearance on the market several years ago and were primarily designed to be more compact and portable than the standard HHMD. They are approximately half the size of a standard hand wand, enabling them to be clipped easily to the belt of a police officer or security guard without being heavy or cumbersome to carry or use. The tactical metal detector took a little while to be accepted by the security industry, partly because the first tactical device on the market also had the very first vibration alert feature and omitted the familiar audio beeper/light-type alarm indicator. Today, however, the tactical HHMD with its vibration alert is accepted as an industry standard product, although it offers only an average level of performance and is used mainly for the detection of larger, more commonplace objects.

Even with all the new innovations being developed in the field of metal detection, it is interesting to note that a number of imported versions – and, in some cases, counterfeit copies – of old-style hand wand devices are still finding their way into professional security scenarios. Some cost as little as £25, and all too commonly they have undergone no proper safety testing and are not certified for safe operation on people; they could even be potentially life threatening. The general performance and reliability of these products is extremely poor, in some cases they are not able to detect even the most commonplace objects reliably. They also often malfunction within just a few days.

It is perhaps surprising, then, that price remains the most significant consideration for purchasers of handheld metal detector products today. Very often, the misperception that all HHMD are fundamentally the same (which, quite clearly, they are not) results in inferior products being purchased in favour of professional quality equipment. Often, the wrong type of equipment or cheaper, lesser models are purchased because budget requirements are seen as more important than true product performance and reliability for the real task in hand.


Robert Adams is the owner of Adams Electronics and has been involved with the company since 1972. The company currently manufactures highly specialised high-sensitivity metal detection equipment for the professional security industry