"Smart patches" can already do more than just cover wounds: Equipped with appropriate sensor technology, they monitor body parameters such as temperature, moisture, pH, oxygen saturation and electrical potentials. But what goes on beneath the surface of the skin remains hidden from the sensor plasters available today. As part of the EU project ULIMPIA, researchers are developing a sensor patch that can also detect physical processes deep inside the body - such as measuring blood pressure or monitoring the bladder.