AR glasses, smartwatches, and other electronic devices present a wealth of interactive capabilities. Of course, you’re not going to carry around a full-sized keyboard with you at all times to control such gadgets, so alternative input methods are needed. While there have certainly been attempts at such an interface, researchers at the Ulsan National Institute of Science and Technology if South Korea have developed "Nailz," a novel interface method using touch-sensitive fingernails.
Although this might seem like an impractical augmentation upon first glance, the team’s research paper argues that faux nails are already implemented for purely aesthetic reasons. Since they’re easily accessible, why not make use of what may already be there?
Their study identified 144 total input methods using a person’s five digits, including 37 nail taps, 11 flicks, and 96 swipes. 29 of these gestures were selected as being easy to execute and distinguish, resulting in a mean input accuracy of 94.3 percent. The input method is demonstrated in the video below, allowing the wearer to interact with smart glasses with only his hands.
The system was prototyped with flexible nail-mounted PCBs, along with an MPR121 chip that handles capacitive touch sensing and a wrist-worn IMU for movement tracking. Each of the five nails were wired into an Arduino MKR WiFi 1010 board using lightweight 32 AWG wire.
Nailz is still very much a prototype, but given that cosmetic artificial nails are already commonly used, one could see this becoming an extremely viable input option.