Smartphones, MP3 players, sports electronics devices such as pulse meters or trackers, medical equipment such as tonometers, pacemakers of the heart, or insulin pumps: An increasing number of electronic companions make daily life easier for us. But as useful these smart helpers may be: Their constant hunger for electricity is a problem. The solution: power supply by means of energy produced by body movements. This is the research subject of scientists at the Karlsruhe Institute of Technology (KIT).