twenty-five lattice regions (cells) are recorded in real time. By addressing and monitoring the positive output voltage signals in the twenty-five lattice regions, the touch information of finger can be obtained. When the finger slides on the sensor along a specific path, the voltage of the region that the finger passes through rises to a peak. I n this regard, a 2D contour plot of the values of the output voltage from all electrodes is obtained, which explicitly indicates the moving path of the finger. Since the interval between two neighbouring regions is a constant that is pre-determined when constructing the grid structure, the location of the object can be inferred readily. More importantly, the trajectory, velocity and acceleration of the object can be derived through analysis and calculation. 

The 2D sensor 10 may be fixed on the platform of a linear motor, and the characteristic may be calibrated by setting different speeds of the linear motor. I n the experiment described herein, the sensor 10 is moving with the motor and the finger is stationary relative to ground. Figures 18(a-c) show the measured voltages when the finger slides on the sensor 10 with different velocities. By simply dividing the distance between two regions by the time taken to cover the distance, the velocity from one electrode to another can be derived. The displacement of the finger sliding with time can be easily derived, which is presented in Figure 18(d). Figures 18(e-g) demonstrate the ability of the sensor 10 to detect accelerated motion of a finger sliding with different accelerations. The ratios of the opposite voltages can be used to calculate the trajectory of the finger as it slides, and the acceleration of the motion can be calculated combined with the time of the voltage interval. The displacement of the finger sliding with time can be easily derived, which is presented in Figure 18(h). Because the velocity and acceleration of the sensor 10 are preset by the linear motor in the presently described experiment, the calculated velocity and acceleration are essentially in agreement with the preset value, ignoring the influence of the slight jitter of the finger. 

I n the discussion above, testing of the 2D sensor 10 is described. Based on a similar analogue location principle, a stretchable I D sensor 12 may also be devised and tested. The El’ end of the I D sensor 12 may be fixed, while the E2’ 

