“…Table 1 provides an overview of the research background on piezo-resistive sensors. According to Table 1, the main parameters affecting the sensing performance of the sensor are the substrate material [11][12][13] (e.g., twocomponents room temperature vulcanizing silicone (Silicone RTV2), polydimethylsiloxane (PDMS), Ecoflex, and thermoplastic polyurethane (TPU)), sensory element materials (e.g., graphene, [14][15][16] graphite, [17,18] carbon nanotubes (CNTs), [19][20][21][22][23] nanoparticles and nanowires [24] ), manufacturing method (e.g., 3D printing, [25] mixing, [8,17,26,27] coating [14,28] and layer compositing [3,18] ), and the structure of the sensor (e.g., conventional material, re-entrant auxetic structures, [8,18,29] constant Poisson's ratio (CPR) auxetic structures [17] and planar isotropic auxetic structures [30] ). The fourth case shows the connection between mechanical and electronic properties.…”