uTouch: Sensing Touch Gestures on Unmodified LCDs

Keyu Chen, Gabe Cohn, Sidhant Gupta, Shwetak Patel


Current solutions for enabling touch interaction on existing non-touch LCD screens require adding additional sensors to the interaction surface. We present uTouch, a system that detects and classifies touches and hovers without any modification to the display, and without adding any sensors to the user. Our approach utilizes existing signals in an LCD that are amplified when a user brings their hand near or touches the LCD's front panel. These signals are coupled onto the power lines, where they appear as electromagnetic interference (EMI) which can be sensed using a single device connected elsewhere on the power line infrastructure. We validate our approach with an 11 user, 8 LCD study, and demonstrate a real-time system.