by Rachael Hutchings
Martin Weigel, and his colleagues at Saarland University in Saarbrücken, Germany, have undertaken some incredibly interesting research regarding the use of what one may consider a blemish or imperfection on their skin to a technological advantage by using ultrathin temporary electronic tattoos. Weigel states that ‘people intuitively know the location of their own bumps and birthmarks’ which reinforces the modern concept of using these as locations for accessing touch-sensitive buttons on smart-phones and other similar devices. For example, if this innovation takes off, freckles could be squeezed to answer a phone call, or sliding a finger over your knuckles could change the volume of your music.
The non-permenant tattoos are known as SkinMarks, and are thinner than the width of a strand of human hair. They are transferred onto the skin using water like a conventional temporary tattoo and roughly two days before rubbing off. Team member Jürgen Steimle, also at the University, says that the team are hoping to ‘make use of the elastic properties of the skin’, stretching and bending, for example. ‘By having the tattoos responsive to changes in the skin surface, they incorporate multiple commands at one location’ he adds. Further examples of what he means by this are as follows; one would be able to adjust your smartphone phonecall volume by sliding one finger across a tattoo placed along the side of a different finger. But bend the tattooed finger and what was previously the volume slider could be interchangable and then become a play and pause or on and off button. In a similar fashion, tattoos on each of the knuckles could act as four different, distinct buttons when the hand is forming a fist shape, but then act as one long slider when the fingers are fully extended.
The team also fantasises about the further possibilities regarding app use with the idea of the electroluminescent properties of these touch tattoos, which glow when a current passes through it. Tattoos could be produced to represent the icons of the apps one uses the most, which would light up upon recieving a notification. To test the tattoos, the team at Saarland University connected them to a computer, but they hope that future research will allow them to link the tattoos to Android smartphones. “We’ve tested the technological feasibility, the next step is to look at implementing it in a practical way,” hopefully suggests Weigel.
One obvious hurdle the team must face is making the microcontrollers used to transmit signals from the tattoos to a computer or smartphone small enough to be practical. For this study, Weigel’s team used copper tape to connect the tattoos to a small Arduino microcontroller attached to the body with a wristband. This seems idealistic, however the corresponding circuit boards would be uncomfortable and too large to wear on other body parts. Chris Harrison, director of the Future Interfaces Group at Carnegie Mellon University thinks that this research is world-leading, and ‘that could be used by artists, programmers and hobbyists’. He also adds that ‘the human skin is extremely nimble’ which along with it’s greater surface area than the average touchscreen, offers plenty of room for logical development of this idea over the next ten years.