Over time, personal computing has shrunk and become more intimate, from the desktop computer to the laptop, smartphones and tablets, smartwatches and smart eyewear. However, the next generation of wearable computer technology, which will be used for health and wellness, social interaction, and a variety of other applications, will be much closer to the user than a watch or glasses: It will be stuck to the skin.
On-skin interfaces, sometimes known as “smart tattoos,” have the potential to beat existing wearable sensing capabilities, but balancing comfort and durability has proved difficult. Members of Cornell’s Hybrid Body Lab have developed a skin-tight interface that is simple to attach and remove and may be used for a number of reasons ranging from health monitoring to fashion.
Pin-Sung Ku, a doctoral student and lab member, is the principal author of “SkinKit: Construction Kit for On-Skin Interface Prototyping,” which was presented at UbiComp ’22, the Association for Computing Machinery’s annual joint conference on pervasive and ubiquitous computing, in September.
“We’ve been working on this for years, and I believe we’ve finally sorted out a lot of the technical issues,” said Cindy (Hsin-Liu) Kao, senior author of the paper and assistant professor of human-centred design at the College of Human Ecology. “We intended to establish a modular approach to smart tattoos, making them as simple to assemble as Legos.”
SkinKit, a plug-and-play technology aimed at “lowering the floor for entrance” into on-skin interfaces for users with little or no technological skills, is the result of many hours of creation, testing, and reconstruction, according to Kao. Kao’s lab is also sensitive to cultural variations in general, and she believes it is critical to deliver these gadgets to varied communities.
“People from various cultures, backgrounds, and races may see these technologies quite differently,” she added. “We believed it was really quite vital to give more people a voice in deciding what these smart tattoos should accomplish.”
The temporary tattoo paper, silicone textile stabiliser, and water are used to create a multi-layer thin film structure known as “skin cloth” by the group. The layered material can be cut into desired shapes—the researchers used three-quarter-inch squares for their study, with male-female cutting lines to allow the pieces to be tessellated (joined together)—and fitted with miniaturised flexible printed circuit board modules to perform a variety of tasks.
“The first step was to locate an acceptable form factor and then scale it,” Ku said. “And the tessellation pattern is used to scale it. As a result, the user may create a circuit and then personalise the architecture by connecting different modules.”
One of the advantages of its design, according to Ku, is its reusability.
“The person may effortlessly connect and remove them,” he said. “Assume that today you want to use one of the sensors for one thing and tomorrow you want to use it for something completely different. Simply separate them and reuse part of the modules to create a new gadget in minutes.”
To put SkinKit to the test, the researchers enlisted the help of nine people with STEM and design expertise to develop and wear the devices. Their feedback from the 90-minute session influenced additional changes, which the group implemented before performing a bigger, two-day research with 25 individuals with STEM and design backgrounds.
The 25 study participants created devices that addressed the following topics: health and wellness, such as temperature sensors to detect COVID-19 fever; personal safety, such as a device that would help the wearer maintain social distance during the pandemic; notification, such as an arm-worn device that a runner could wear that would vibrate when a vehicle was nearby; and assistive technology, such as a wrist-worn sensor for the blind that would vibrate when the wearer was about to fall.
Other uses included social, fashion, and athletic training.
Over the summer, members of Kao’s lab, including Ku, attended the 4-H Career Explorations Conference, where they helped around ten middle-schoolers from upstate New York develop their own SkinKit devices.
“I believe it simply gives us a lot of promise for STEM learning, and particularly for engaging those who would not have been interested in STEM,” Kao said. “However, I believe there is a lot of potentials for it to engage the next generation and larger demographics to explore the future of smart tattoos by merging it with body art and fashion.”
