Figure 5.

Inertial signal detection: (a) bottom view of motion sensing patch. Reprinted with permission from Ref. [71]. Copyright 2020 John Wiley and Sons, (b) optical images and an exploded view schematic illustration for a core/shell structure. Reprinted with permission from Ref. [72]. Copyright 2015 John Wiley and Sons, (c) schematic diagram showing the T−ball device structure (left), operation mechanism of the T−ball under in−plane vibration along x−axis (middle), and the acceleration level and the output voltage from different type of exercises (right) Reprinted with permission from Ref. [73]. Copyright 2017 John Wiley and Sons.