I n another example embodiment, through integrating two 2D control devices e.g. on both sides of a card, a 3D control (x, y, z translation and rotation) in free space can advantageously be realised, as shown in Figure 6(b), Figure 7 and Figure 8 . Figures 7(a),(b),(c) show a 3D control device 500 supported on a hand, in front side view and in back side view, respectively. Respective fingers are used for sliding on the front and back side of the device 500. Figure 7(d) shows the output signal 501 from the front side 2D control device single electrode 502 when the finger on the front side of the device 500 is moved along the different directions (+/-x and +/-y directions as shown in Fig. 8(a)). Figure 7(e) shows the output signal 503 from the back side 2D control device single electrode 504 when the finger on the back side of the device 500 is moved along the different directions (+/-x and +/-y directions as shown in Figure 8(a)). Figure 8(f) shows the output signals 505, 507 from the front and back side 2D control device single electrodes 502, 504 when the two fingers on the front and back side of the device 500 are moved simultaneously along the different directions (+/-x and +/-y directions as shown in Figure 8(a)). I n an example embodiment, when both fingers slide towards the +x or -x direction, the controlled object is programmed to move one step in the +x or -x direction correspondingly. Figure 8(c) shows the front and back single electrode output signals 600, 601 when both fingers slide in +x direction followed by sliding in - x direction. Similarly, when both fingers slide towards +y or -y direction, the object is programmed to move one step in +y or -y direction correspondingly. Figure 8(d) shows the front and back single electrode output signals 602, 603 when both fingers slide in the +y direction followed by sliding in the - y direction. I n order to control the object to move in the +z or -z direction, the front finger (on the front side) slides consecutively across +x and +y, or conversely +y and +x. Figure 8(e) shows the front single electrode output signal 604 when the front finger slides consecutively across the +x and +y directions, followed by sliding consecutively across the +y and +x directions. When the front finger slides towards the +x direction and the back finger slides towards -x direction, the object is programmed to rotate one step in the +6y direction (as shown in