The object of the BBCI project is to steer computers with thoughts. This technology will allow heavily paralyzed people to use communication tools or control wheel chairs. The researchers aspire to allow untrained people without long training sessions to use this technology. This will be achieved by measuring the brain waves in form of the electroencephalogram (EEG) with electrodes attached to the scalp. The brain activity reflects already the imagination of a behaviour. If the proband thinks of his hand, the cursor moves up, if the thinks of this foot, it moves down. One of the main difficulties for the researchers is correctly interpreting the very weak and noisy signals a thought produces on the top of the scalp. Complex filter procedures have to be programmed which can filter the decisive signals out of the data tangle. For this a phase of calibration lasting approximately half a hour is currently needed, in which the system learns to correctly interpret the proband’s signals. If this has been concluded, two thirds of probands are capable of moving an icon on the screen in the desired direction simply through the power of their thoughts.