Skin-Inspired Bimodal Magneto-Dielectric-Based Flexible and Sensitive Capacitive Sensor for Limb Motion Tracking

Flexible devices featuring bimodality finds wide application in wearable electronics for tracking simple-to-complex human activities. Such tracking requires high sensitivity and broad working range which is still a con-cern for wearable electronics. Herein, a magneto-dielectric layer (MDL)-based bimodal sensing (strain and proximity) device with a broad working range and higher sensitivity is proposed. Nanoparticles in MDL (magnetic nanoparti-cles (MNP) within the PDMS matrix) change their posi-tion dynamically (g -> g) according to different bending load conditions. Increased sensitivity (SST asymptotic to 4x-times and SProx asymptotic to 1.5x-times) and wider working range (from 6 to 20 mm) are achieved in contrast to regular devices with PDMS as a dielectric. Linear device response (0.99 coeffi-cient of linearity), long-endurance (1000 cycles), and rapid detection (200 and 250 ms) features add further advan-tages. Single capacitive readout and standard interdigi-tated electrodes (IDEs) simplify the device implementation. Moreover, IDE design automates contactless sensing along with identification of the nature of the sensing object (con-ducting/nonconducting), which is applied directly when it comes to object-sensitive human perception (e.g., visually impaired person).