In 2015, scientists from the University of Saarland presented their development iSkin - small stickers on the skin that respond to touch and send a signal to a smartphone. Today this technology has matured to the creation of full-fledged touch interfaces, which are called Multi-Touch Skin. It will allow the transmission of commands through an arbitrary area of human skin.
To activate Multi-Touch Skin, a sticker must be printed, which consists of an array of thin electrodes placed between the PET layers. The wires are connected to the power source and the controller, which sends the signal for processing to the Raspberry Pi Zero microcomputer. It takes about a minute to print a sticker, it can be of any shape and is glued on the wrists, shoulder, behind the ear or on the chest, at the request of the user.
When you touch the sticker, the finger contacts the electrode, which changes the electrical capacitance at a specific point - this is the signal for processing, by analogy with the smartphone screen. The complexity and variety of control gestures is limited only by the area of the sticker and the algorithms of the system. For example, a swipe behind the ear adjusts the volume of the music, and near the eyes adjusts the brightness of the lighting system.
To date, the developers of Multi-Touch Skin have created four optimal label formats. On the neck, on the side and on the back, to control the headset and similar wearable electronics. A bracelet on the wrist, for binding to an external device - a smart vacuum cleaner, a robot, etc. The sticker on the back of the hand will receive communication with messengers in the smartphone for receiving and transmitting calls. And a sticker on the forearm to quickly unlock or disconnect your smartphone.