fig3

Figure 3. P-HMIs for IoT. (A) Schematic diagram of an IoT HMI system controlled by a pavement block piezoelectric energy harvester. Reproduced with permission from ref.^[63]. Copyright 2019, Elsevier. (B) Conceptual design and possible applications of a smart pen based on a piezoelectric energy harvester. Reproduced with permission from ref.^[64]. Copyright 2021, Elsevier. (C) Photograph of flexible PEH-based sensor arrays for HMI. (D) Working mechanism of flexible tactile sensor-based smart door lock. Reproduced with permission from ref.^[65]. Copyright 2022, Elsevier. (E) Schematic overview of a smart keyboard application using flexible piezoelectric sensors. Reproduced with permission from ref.^[27]. Copyright 2022, Elsevier. (F) Dynamic voltage output of three adult subjects when typing the word “DIY” on the keyboard attached with PMNP textiles. Reproduced with permission from ref.^[66]. Copyright 2021, Elsevier. (G) Photograph of a wireless switch system to achieve the real-time smart home control of a table lamp, an air conditioner and an air purifier. Reproduced with permission from ref.^[67]. Copyright 2018, Elsevier.