Metamaterials are a class of materials that exhibit a behaviour that cannot be found in nature [1, 2]. Their unusual behavior derives from their inner structure’s design and arrangement, rather than their chemical composition [3]. They have been applied in different fields ranging from optics [4] to mechanics [2, 5, 6]. In the realm of mechanical metamaterials, auxetic materials consist of structures that exhibit essentially negative [7] or zero Poisson’s ratio [8], which means a longitudinal expansion of the auxetic material is followed by a transversal or no expansion at all, in- stead of a shrinking, which is observed in ordinary materials [9]. This counterintuitive behaviour is enabled by the rotation of non-deforming smaller components that constitutes the unit cells [7]. In mechanical applications, normally the auxetic structures are fabricated as a single structure explored in different mechanical and medical applications, such as impact absorbers [10], cardiovascular stents, and protective equipments [11]. Furthermore, there has been limited exploration into the development of modular unit cells that can be assembled into larger structures. Such unit cells can be designed with highly nonlinear mechanical responsens, featuring tensile instabilities that can drive the entire metamaterial in multiple metastable configurations [12], a very attractive property for the control of soft robots. Similarly, there have been few efforts to utilize these structures as stretchable sensors, or as platforms for sensors, by leveraging the unique characteristics of the rotating or non-deformable parts of the unit cells. Herein, we designed and fabricated a silicone-based auxetic buckling 3D unit cell that presents two mechanical configurations. The unit cells can be assembled to form larger 3D auxetic structure. To explore the rotating mechanisms of the unit cells, self made capacitive sensors were fabricated and embedded in the rotating parts to indicate the mechanical state of the unit cell. To check the critical loads for the buckling effect, a Finite Element Analysis (FEA), along with a dynamic modelling were also developed. This design is envisioned for creating a platform for soft machines, in which from simple buckling unit cell, more complex structures can be developed, such as soft robot arms.