Definition of metal detectors

Metal detectors are electronic devices designed to locate and detect the presence of hidden metal objects, whether in the ground, inside products or in structures. They work by emitting and receiving electromagnetic fields that interact with ferrous and non-ferrous metals, which allows the presence of these materials to be identified without direct visual contact.

These devices are used in various industries and fields, from security at airports and mass events, to the inspection of food or pharmaceutical products, through archeology and construction. Its technological development has advanced considerably, incorporating digital systems, advanced sensors and discrimination capabilities to improve its precision and efficiency.

Electromagnetic fundamentals

Metal detectors operate primarily through the generation of an alternating electromagnetic field using a transmitter coil. When this field comes into contact with a metal object, it induces eddy currents in the metal which in turn generate a secondary electromagnetic field detectable by a receiving coil.

This process is based on the conductive and magnetic properties of metals, which modify the original field in a characteristic way, allowing the detector to identify the presence and, in some cases, the type of metal detected. The sensitivity of the device depends on the operating frequency and the configuration of the coils.

There are different technologies in metal detectors, the most common being pulsed induction and very low frequency (VLF), each with particular advantages in terms of detection depth and material discrimination.

Signal types and processing

After capturing the electromagnetic field modified by the metal, the detector converts these signals into useful information using electronic circuits. Digital processing allows you to filter out environmental noise, identify the characteristic signal of metal and discriminate between different types of objects.