I n electrode grid designs according to example embodiments, the electrode grid may be formed directly on a substrate to provide an uncovered design, or may be formed on a substrate and further covered with a dielectric layer (for example, a thin layer without any patterns, or a layer with the same pattern as the grating electrode). For embodiments according to the uncovered design, the contact object can be made from electronegative material. For the covered design, if the cover layer is formed from an electropositive material, then an electronegative material is preferably used for the contact object in order to maximise the output performance. If electronegative material is adopted as the cover layer, then electropositive material is preferably used for the contact object, such as a human finger etc. I n example embodiments the electrode grid may be made from an electropositive material, such as a metal. I n other example embodiments, the electrode grid may comprise grating structures made from an electronegative material and a conductive path to collect the triboelectric charges from the electronegative material. Due to the elegant structure design and operation mechanism, only one electrode is advantageously needed for in-plane 2D controlling according to example embodiments. Furthermore, two electrodes fabricated on both sides of a thin substrate (for example) such as paper or a card can achieve 3D controlling in free space according to example embodiments. As shown in Figure 4, grating structures with varying electrode number or electrode width can be configured into electrode grid designs according to different embodiments to achieve multiple direction control in 2D space under triboelectric based sliding single electrode mode, e.g., square four-direction designs 100, 102 (Figure 4(a), (b)), circular four-direction design 104 (Figure 4(c)), eight-direction design 106 with varying electrode number