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Smart watch with a projector turned a hand into a touch screen

Robert Xiao / YouTube

American and Chinese engineers have created a prototype of smart watches that use the user’s hand as a screen. A small projector projects an image, and distance sensors track finger touch on the skin, the authors report in an  article presented at the CHI 18 conference.

One of the main problems of smart watches is the difficulty of outputting and entering information – on common watches, the screen is too small to read a large amount of text from it or to display an interface with a large number of elements that, moreover, are difficult to press with your finger without missing Simply increasing the size of the screen does not solve this problem, because in this case the clock will be too bulky and it will still be inconvenient to use them, although not because of the small screen. One solution to the problem is to use the user’s hand as an additional space for input or output.

Engineers from Carnegie Mellon University and ASU, led by Chris Harrison, decided to use the hand as the only I / O interface for smart watches. In the prototype developed by them, there is no familiar screen; instead, a picoprojector with a brightness of 15 lumens and a resolution of 1024 by 600 pixels, as well as an array of infrared sensors, are installed on the side face of the device. They periodically emit infrared pulses and determine the distance to the object in time between the radiation and reflection. Combining the readings of several sensors, the watch can quite accurately determine the position of a finger on a hand.

Since the projector is parallel to the arm, the image from it is strongly distorted. Researchers taught the software to adapt the image itself and its brightness so that its projection on the arm was as undistorted and uniform in brightness as possible. In addition, they provided for the dynamic calibration of the position of the clock relative to the hand. Before you start interacting with the clock, the user needs to hold the interface slider on the arm. At this time, the clock records the position of the finger during the gesture, and comparing it with the displayed image, determine the angle of the clock relative to the hand.
The developers have demonstrated the work of the prototype clock on video:

Previously, ASU and engineers from Carnegie Mellon University have already presented similar developments. In 2016, ASU showed a concept of watches with similar functions, using a hand as a screen and a surface on the watch itself as a touchpad, but never showed a real device. At the MWC 2018 exhibition, Haier associated with ASU showed a working prototype of ASU Watch smart watches with a touch screen, as well as a projector that displays the image from the watch on the hand. And in 2016, engineers at Carnegie Mellon created aReadings of several distance sensors

Robert Xiao et al. / CHI 18 smart watch without a projector, but with two electrodes capable of tracking fingertips to the user’s hand.

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