1. A system for manipulating or sensing the presence of an object, comprising: at least one polymeric substrate including a plurality of non-metallic sensing electrodes, wherein said non-metallic sensing electrodes are flexible, and wherein said non-metallic sensing electrodes are adapted to sense changes in electrical impedance when disposed at or in proximity to said object; and a computer processor electrically coupled to said plurality of sensing electrodes and programmed to (i) measure signals indicative of a change in impedance of at least a subset of said non-metallic sensing electrodes, (ii) execute an electrical impedance tomography algorithm to determine, from said signals, one or more forces applied to said polymeric substrate, and (iii) based on said one or more forces, determine one or more characteristics indicative of a normal force or a change in normal force between said object and said polymeric substrate.