We present iSoft, a single volume soft sensor capable of sensing real-time continuous contact and unidirectional stretching. We propose a low-cost and an easy way to fabricate such piezoresistive elastomer-based soft sensors for instant interactions. We employ an electrical impedance tomography (EIT) technique to estimate changes of resistance distribution on the sensor caused by fingertip contact. To compensate for the rebound elasticity of the elastomer and achieve real-time continuous contact sensing, we apply a dynamic baseline update for EIT. The baseline updates are triggered by fingertip contact and movement detections. Further, we support unidirectional stretching sensing using a model-based approach which works separately with continuous contact sensing. We also provide a software toolkit for users to design and deploy personalized interfaces with customized sensors. Through a series of experiments and evaluations, we validate the performance of contact and stretching sensing. Through example applications, we show the variety of examples enabled by iSoft.
Figure 2. Proof-of-concept toolkit showing (A) overall interface, (B) interface customization, (C) electrode placement, (D) guidance template, and (E) prototype