SENSOR HAVING FERROGEL WITH MAGNETIC PARTICLES

摘要

A sensor for detecting a condition includes a hydrogel configured to change thickness or volume in response to the condition. Magnetic particles are arranged in the hydrogel so that a magnetic property of the hydrogel changes with changes of thickness or volume of the hydrogel. Some such sensors include a magnetic-field detector that measures the magnetic field of the hydrogel. Other such sensors include a device coil is arranged with respect to the hydrogel so that changes in the magnetic property modulate an electrical property of the sensor. A sensing system using such a sensor includes a reader spaced apart from the sensor and including a reader coil and a resonance detector coupled to the reader coil to detect a the resonant frequency of the sensor. Changes in the magnetic property detectably modulate the resonant frequency.