PhD candidates at the MIT Media Lab have demonstrated a technique for producing customizeable user interfaces in the form of temporary decorative tattoos. The researchers used gold leaf to construct a range of sensing surfaces for capacitive touch input, conductors for heat-sensitive displays, and antennae for short-range wireless communications, all with jewelry-like aesthetic appeal.
The researchers outline a method for rapidly designing and crafting the interactive tattoos, dubbed DuoSkin, using mostly basic and inexpensive components and tools. Gold leaf is relatively inexpensive, and is safe for long-term skin contact—it has notoriously even been an ingredient in haute cuisine.
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The interfaces achievable with the method include buttons, sliders, and even X-Y grid controllers, with the potential to act as anything from a trackpad to a presentation controller to a musical instrument interface.
Displays made using the technique incorporate so-called ‘thermochromics,’ relatively low-resolution pigment sheets that shift color when heated. The researchers were able to control the color by running gold-leaf circuits through the color-shifting material. In one proof of concept, they built an application that allowed couples to share their moods by changing the color of one another’s decorative tattoos.
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Finally, the team gave their tattoos wireless capability by using Near-Field Communication (NFC) chips attached to spiral gold-leaf antennae. NFC chips draw power from the device that reads them, so they don’t need batteries, and users can update the data they emit using a smartphone app.
The MIT team, who collaborated with members of Microsoft Research on the project, claim that the material is also more durable for everyday use than existing skin-surface interfaces.
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Though the focus of the paper is frequently on aesthetics and novelty, skin-based interfaces have plenty of serious potential. They could be particularly useful for medical monitoring—for instance, displaying glucose levels continuously to diabetics. They could also serve as seamless extensions of wearable computers, such as smartwatches.
There’s another far-out potential here. Though progress has apparently been minimal, some members of the extreme body modification community have experimented with permanent tattoos using gold leaf, raising the possibility that such interfaces could become permanent implants.
The DuoSkin research will be presented publicly at the International Symposium on Wearable Computers, taking place in Heidelberg, Germany from September 12th to 16th.