A new patch can turn any part of the body into a touchscreen that is just as sensitive as your smartphone screen. And it can be operated using more than one finger.

Let's imagine: you're behind the wheel when your telephone rings. Taking the call is against the law, and even simply pressing 'accept' is unsafe. After all, you need to locate the button, and that half-second distraction can be dangerous.

But imagine you could pick up your phone by quickly scratching behind your ear. This is now possible using a new type of plaster, designed by scientists at Saarland University in Germany. They have created a plaster which behaves like the touchscreen of your smartphone, but can be applied to your body. This allows any part of your body to become a touchscreen.
 

INTUITIVE

Such touchscreens can be useful because people know exactly where everything is located on their body. Operating a touch interface via a body patch therefore works much more intuitively than when using a screen. Until now, however, these body sensors have been pretty limited: they could not deal with subtle touches or movements of more than one finger at a time.

That is now set to change. The new German patch can be created in any shape and has two layers of electrodes. The electrode layers are superimposed on one another to form a grid. A sensor measures the grid capacity, which changes when someone touches the grid. The same technique is used under the glass of a smartphone, but has now been applied to a flexible sticker.
 

PRINTED

It proved to be no simple task to produce such a grid in any random shape. The researchers needed to develop design software that calculates the electrode network on the basis of the required shape. A (3D) printer then creates the grid.

The researchers started by creating a patch to fit behind the ear. Swiping up or down allows you to adjust the volume of the music you're listening to, and swiping left or right selects the previous or next song.

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