fig3

Figure 3. Systematic study of the SWSS signals. (A) Triboelectric discharge mechanism of sharp-tip electrodes; (B) COMSOL simulation model of electrodes with sharp tips; (C) Simulation results under different tip distances; Time-domain (D) and frequency-domain (E) diagrams of SWSS signals. SWSS: Self-powered wireless sensing system; NBR: nitrile butadiene rubber; PTFE: polytetrafluoroethylene; PI: polyimide; LIG: laser-induced graphene.