Steel health monitoring device based on Hall sensors

Magnetic Harvester for an Autonomous Steel Health Monitoring System Based on Hall Effect Measurements

“…For a sinusoidal input, , at resonant frequency , ( ) the power delivered to the load, , is calculated to be: as a result, some basic parameters of the circuit are summarized in the following list [ 17 ]: The inertial mass inside the coil must be the largest possible; The external oscillation’s frequency and the resonant frequency of the inertial mass must be as close to equal as possible; The oscillation of the inertial mass must not be prohibited by the shape of the generator; R c (the generator’s internal resistance) must be one or more orders of magnitude less than R L (the resistance of the load); The system’s mechanical damping should be as little as possible; k e (the electromagnetic constant) should be such that the generator’s mechanical internal resistance is close to equal to the load’s resistance ( R L ≈ k e 2 / d m ). …”

“…At the free end of each pole, a Hall sensor is placed. A detailed description of the operating principle of the arrangement can be found in [ 17 ]. However, the dimensions, the electronics, as well as the packaging of the current arrangement have been modified in order to produce a more sensitive, robust, and energy-efficient device.…”

Magnetic Micro and Nano Sensors for Continuous Health Monitoring

“…While Hall sensors are often used in the structural health monitoring of buildings or machines [96][97][98], only a few examples of Hall effect sensors for medical purposes can be found in the scientific literature. Hall effect biosensors were described by Liu et al, who showed that a Hall sensor made from a single graphene layer with guanine-rich DNA immobilized on the graphene's surface had a very high potassium ion specificity and very low detection limit [99]; however, while potassium is an important substance for the human body, this sensor was not developed further for long-term measurements.…”