Adding input controls and sensors to RFID tags to support dynamic tangible user interfaces.

ABSTRACTProviding high resolution tangible user interface components without batteries such as dials and sliders that support dynamic user interface arrangement is challenging. Previous work uses RFID to support limited resolution custom-built components. We demonstrate improved techniques using commercial off the shelf input controls incorporated into passive RFID tags using an on-off key subcarrier to encode state information into the RFID signal. Our method supports high resolution components that do not require power cables or batteries. We provide exemplars demonstrating how the technique supports a range of user interface components including buttons, dials, sliders, flex and light sensors. Compared to previous work, we obtain a higher resolution, only limited by sample time, for all components and demonstrate 115 discrete dial positions. Our technique allows the TUI components to be freely placed and rearranged without hardwiring or batteries.