Abstract
Integrating interactive interfaces into everyday items is crucial for connecting the digital and physical worlds. However, many current interface technologies are obtrusive and difficult to integrate into the environment. This work presents eStone, an approach where natural stone surfaces are used as substrates for capacitive thin-film sensors acting as interactive interfaces. metallic thin films such as 200 nm-thick aluminum (Al) were sputter deposited and structured on a range of different stones, including marble, granite, porphyry, and limestone, creating conductive patterns and enabling the realization of capacitive sensors. The nanometer-scale thickness of these layers preserves the stone’s natural appearance and texture and transforms them into functionalized and durable capacitive sensors. Combined with through-hole contacting vias and customized conventional readout electronics, eStone demonstrates excellent performance when used as a capacitive controller to adjust the volume of a loudspeaker or the temperature of a thermostat.