You've heard of e-mail. Now, there's e-nail.

Researchers at the MIT Media Laboratory announced this week that they have devised a trackpad that fits on your fingernail, and allows you to control devices with a simple touch. The device, called NailO, will be introduced next week in a paper presented at the Association for Computing Machinery’s Computer-Human Interaction conference.

The NailO is made up of capacitive sensors (the same type used in your iPhone's screen) plus a battery and a small Bluetooth chip that communicates with your phone, tablet or other device. Copper electrodes are printed on a thin sheet of polyester, which is then placed over the top of a chip containing the Bluetooth antenna. The device, which is still in prototype, was inspired by the popularity of nail art stickers in countries like South Korea, according to Cindy Hsin-Liu Kao, one of the MIT graduate students behind the project.

The researchers envision that NailO could one day be part of a combination of wearable input devices that people use to control nearby screens and gadgets. A fingernail trackpad could be used to control connected devices (e.g. flick your thumbnail, and your wireless-connected light bulb changes color), conduct basic navigation on a nearby screen, and even send discrete messages, in settings when pulling out a phone or looking at a smart watch would be uncouth.

There's little doubt that, in the future, we'll control our digital surroundings using a variety of wearable devices. Right now, technologists are putting a lot of stock in self-contained wearable devices like the Apple Watch — which have both input methods and screens to display the results of those inputs. But there will also be a place for wearable devices that serve as input-only controllers for different types of connected devices — the kind that could be used to turn on your air conditioning one minute, and fast-forward a Netflix movie the next.


Battery life, of course, is the most challenging test for any new mini-wearable. The MIT researchers say they've identified a new technology that could shrink a battery down to the size of a fingernail, while keeping it only half a millimeter thick. But until that kind of battery is commercialized, the device will have to sacrifice some utility, either by shutting itself off between uses to conserve power or by needing to be charged frequently.

But if they can make the technology work, the MIT researchers may have created a new kind of wearable that — like the Apple Watch — doubles as a fashion accessory. The study's authors imagine that the NailO would have a detachable face, so that different patterns and colors could be swapped in to coordinate with your outfits. It might not be long until your Mad Men manicure has a tiny computer underneath it.