3D-Printed LightTouch Gadgets Offer Touchscreen Interaction with No Batteries or Active Circuits
With no power of its own, a 3D-printed LightTouch can interact with touchscreen devices as though it were a finger.
Researchers at the Tokyo University Institute of Technology, the University of Tokyo, and Yahoo Japan have revealed details of LightTouch, a 3D-printed passive gadget designed to automate touch inputs on unmodified touchscreen devices.
"We present LightTouch, a passive gadget to enhance touch interactions on unmodified capacitive touchscreens. It simulates finger operations such as tapping, swiping, or multi-touch gestures using conductive materials and photoresistors embedded inside the objects," the researchers explain. "The touchscreen emits visible light and the photoresistor senses the level of this light, which changes its resistance value. By controlling the screen brightness, it connects or disconnects the path between the GND and the touchscreen, thus allowing the touch inputs to be controlled."
"In contrast to conventional physical extensions for touchscreens, our technique does not require continuous finger contact on the conductive part nor the use of batteries. Our technique opens up new possibilities for touch interaction such as for enhancing the trackability of tangibles beyond the simple automation of touch inputs."
The 3D-printed LightTouch accessory uses a mixture of non-conductive PLA and a filament mixed with graphene to make it conductive. Photoresistors are arranged in a line or a triangle, connected at one end to a conductive contact point placed against the screen and at the other end to the device's casing as a ground point using a simple clip which also holds it in place. What the device doesn't have is any active circuit or battery power — giving it its "passive" designation.
Full details can be found in the paper, published in the ACM Digital Library as part of the proceedings of the ACM Symposium on User Interface Software and Technology (UIST'20).