The intuitive touch screens integral to smartphones caused a sensation when first released, and they remain popular for many consumer electronics. Now, a team from KAUST has found a way to take these input devices into three dimensions with a sensor that tracks the position and speed of human fingers in free space.
Thin films made from carbon nanotubes or graphene oxides have electrical properties that are highly sensitive to humidity.
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Dr. Yanlong Tai and Professor Gilles Lubineau realized that a combination of these tiny nanomaterials could be used to power a recognition system based on gestures rather than touch. “These 3D non-contact sensors,” explained Tai, “require generation of three different signals during a one-time measurement.” The duo envisioned that an appropriate mix of nanotubes and graphene oxides would give triple response patterns—positive-negative-negative, for example, to the natural humidity surrounding a fingertip.
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The researchers used this knowledge to fabricate a flexible, transparent device that measures the distance, speed and direction of a fingertip placed above it. This prototype also worked with vapor from human breath, and it is poised to make gesture sensing a part of digital input interfaces.