Due to increased violence all over the world, security measures in many of the public places have been improved and become more serious. It is now very common that in very crowded places such as the airports, the cinemas and shopping malls, we frequently see walk through metal detectors. They help maintain security in much better levels since they have been proven to be quite useful in detection of dangerous objects including guns or even knives. Apart from the metal detectors, many security personnel are using hand-held types of metal detectors.
Metal detecting devices are compact machines which are based on the system referred to as Pulse Induction (PI). The system indicates a certain coil of wire which is regarded as the transmitter and is placed at the very top of the metal detector to act as a magnetic fields receiver. With the wire, certain pulses of electricity are created while in the meantime, reversing polarity of the inherent magnetic fields. At each second, hundreds of these pulses of electricity get sent; however, it depends on the particular model of the walk through metal detectors being used. Some of these devices can create about 25 pulses per second or even more than 1000 pulses per second.
When any metal object does pass through the field of electromagnetism, it will cause a reflection of a pulse which will only last for a few seconds. Therefore, when the presence of any metal object gets detected, then the sampling circuit sends a signal that will cause beeping. This is that classic beeping sound that you normally hear at the airport or shopping mall when someone carrying metal objects passes through the walk through metal detectors. In most situations, this beep occurs when you have some keys in your pocket or loose change. Even a cell phone can cause this. For this particular reason, you are asked to take out these types of items from your pockets just before going through the metal detector. If the machine does continue to beep even after doing this, you get checked using a hand-held type of metal detector so as to find out the cause of this alarm.
There are many different types of walk through metal detectors. The inbuilt sensitivity of metal detection varies greatly from one to another. For instance, if the sensitivity to metal is extremely high, the beeping sound will always happen even if you just have coins in the pocket or even just piercings and earrings. In the high security areas, highest sensitivity is essential. Having high sensitivity metal detectors in the malls and shopping centers does not make any sense. It will make a lot of noise many times, and the detection of even more dangerous objects like knives or at times guns would become much more challenging.
There are also some portable types of walk through metal detectors. They are used for events which are temporary such as the exhibitions. Portable versions of the metal detectors would be useful in shops, large hotels, shopping malls and are easily purchased through online sites. Some events might require strict safety measures. If someone is planning to organize an enjoyable event and still keep it safe, he or she should opt for the portable devices for maximum security of the premises.
The first of the archway detectors was actually built around the 60´s and at the time it did have a singular industrial use. During the recent years, use of the walk through metal detectors dramatically evolved. Today, they get used for mostly security reasons. There are many places where use of metal detectors is a must. These include schools, concert areas, prisons and public events.