Researchers from the town of Zelenograd (situated near Moscow) have developed an efficient and convenient device for detecting metal objects. It is distinguished from its analogues because it is a highly sensitive method that allows you to detect a razor blade, a coin, or even a small pin in the lapel of your jacket. This magnetosensitive sensor system even enables you to see the contours of objects and identify whether it is made of ferrous or non-ferrous metal.
The device is based on a grid of magnetosensitive sensors which were developed (along with the device itself) by specialists of the Research and Production Complex “Technology Center” of the Moscow Institute of Electronic Technology (MIET). As the developers are taking out a patent for the device and the sensors, they do not disclose their design yet. However, the subject matter is explained as follows.
The “heart” of each sensor is a superfine film of iron, nickel and cobalt alloy, 100 angstroem units thick (one hundredth of a micron). The film structure is heterogeneous with microcrystals forming differently oriented domains in it. The film pattern formed by microcrystal strokes is determined by the parameters of the magnetic field (magnetic intensity and direction of lines of force).
If magnetic field intensity changes, the microcrystals' orientation also changes, which affects the electrical resistance of the film. The object's own magnetic field or degree of distortion of the terrestrial magnetic field, is then recorded and measured. Nonferromagnetic metal objects are detected by the weak magnetism emitted using sensors surrounded by a coil of electromagnetic radiation which has a known emissive power and frequency.
The device can distinguish between metal objects by examining the area at a certain distance, for example, 10 centimeters, and filtering out other objects using a central processor. This processor analyzes data and compares it with reference objects. The object is displayed on an LCD display, much like an ordinary metal detector.