Single-coil metal detector based on spiking chaotic oscillator

Abstract

A remarkable feature of chaotic systems is high sensitivity, which makes them applicable to the construction of sensing devices. Various sensors can be developed based on chaotic oscillators, e.g., metal detectors, salinometers, inductive sensors, and optical sensors. Our study investigates the properties of the metal detector based on Sprott Case N chaotic oscillator equipped with a single inductive coil. A key feature of this circuit is the ability to operate in two modes: chaotic and spiking chaotic oscillations. The last fact makes it possible to consider this circuit as an arti-

Sensitivity Optimization and Experimental Study of the Long-Range Metal Detector Based on Chaotic Duffing Oscillator

“…Figure 17 demonstrates the course of the experiments. Theaccuracy of target positioning at the automated test bench is approximately 50 µm, resulting in a relative error not more than 0.2% in linear displacement measurements [ 15 ]. Figure 18 presents the photograph of the used set of targets.…”

“…In our experiments, we found that when using a stable generator of the harmonic waveform, the analog part of the metal detector also behaves stably, providing, after adjusting the sensitivity, the minimum number of false detections for a long time. At least, the stability of the circuit was found to be much higher than in the study of a metal detector based on the Sprott Case N system [ 15 ]. We believe that this is one of the reasons why the sensitivity of the Duffing oscillator-based detector is significantly higher.…”

“…The last paper in the comparison, ref. [ 15 ], is our previous work on the chaos-based metal detector/proximity sensor. The circuit implements a Sprott Case N oscillator and is equipped with a 130 µH single-layer planar coil.…”

“…A possible schematic of an analog detector is shown in Figure 7. The second type of detector converts the signal of a chaotic oscillator into a signal similar to neuron spikes [14], which makes it possible to apply various effective methods to it, for example, analysis of the distribution of inter-spike intervals and classification of the resulting output using machine learning [15]. This method is applicable to digital computers only, but it is simple and provides great capabilities of recognition using machine learning.…”

“…The convenience of the Duffing and Chua oscillators lies in the fact that the moments when their attractor scrolls are switching can be interpreted as spikes of neurons [ 14 ], which make it possible to apply various effective methods for neuron activity analysis, for example, inter-spike intervals distribution visualization. The spike analysis method proved to be very effective for sensing in our previous study [ 15 ]: we implemented a single-coil metal detector based on a Sprott Case N chaotic oscillator with spiking behavior and demonstrated that the developed metal detector has a continuous response depending on the distance to the target and the target material (steel, aluminum or brass/copper). We compared the developed chaotic sensor with the sensor based on a harmonic oscillator and found that the operating range of the chaotic sensor is at least 20% larger than that of the harmonic one.…”