Bimodal Tactile Sensor without Signal Fusion for User-Interactive Applications

Tactile
sensors with multimode sensing ability are cornerstones
of artificial skin for applications in humanoid robotics and smart
prosthetics. However, the intuitive and interference-free reading
of multiple tactile signals without involving complex algorithms and
calculations remains a challenge. Herein a pressure–temperature
bimodal tactile sensor without any interference is demonstrated by
combining the fundamentally different sensing mechanisms of optics
and electronics, enabling the simultaneous and independent sensing
of pressure and temperature with the elimination of signal separation
algorithms and calculations. The bimodal sensor comprises a mechanoluminescent
hybrid of ZnS–CaZnOS and a poly­(3,4-ethylenedioxythiophene):poly­(styrene
sulfonate) (PEDOT:PSS) thermoresistant material, endowing the unambiguous
transduction of pressure and temperature into optical and electrical
signals, respectively. This device exhibits the highest temperature
sensitivity of −0.6% °C–1 in the range
of 21–60 °C and visual sensing of the applied forces at
a low limitation of 2 N. The interference-free and light-emitting
characteristics of this device permit user-interactive applications
in robotics for encrypted communication as well as temperature and
pressure monitoring, along with wireless signal transmission. This
work provides an unexplored solution to signal interference of multimodal
tactile sensors, which can be extended to other multifunctional sensing
devices.