Three dimensional touchless tracking of objects using integrated capacitive sensors

In this paper, a capacitive motion tracking system is proposed for detecting the motion of a user's hand or finger as s/he interacts with mobile computing devices such as cellular phones and tablets. The main benefits of using capacitive sensing technique over the other existing ones are its low power dissipation, ease of integration, cost effectiveness, and noise immunity. A differential sensing method has been implemented to enhance the robustness and accuracy of capacitance sensing. Simulation results are found to be in good agreement with experimental data in predicting the behavior of the sensing system consisting of sensing electrodes and readout electronics. Experimental measurements demonstrate the applicability of the proposed system in tracking user's finger within a 10cm range from the sensor's plane.