A brain computer interface is a system that enables users to control a computer (or another device with the help of a computer) by using their brain signals.
Although there are various types of BCI implementations, the basic scheme is always true. We’ll go into details of an EEG (electroencephalography) based BCI but other systems such as MEG are also available.
In an EEG based BCI, the electrical activity in the user’s brain is captured by little devices called electrodes which are attached to various places on the user’s head.
These signals are then fed to a computer. The computer analyzes these signals, and decides what to do with them. This might be controlling a robot arm, or using a mouse. In my area of interest, the computer lets the user type.
Based on the analysis, an output information might be displayed on a screen so that the user knows the result of his actions.
On some BCI applications, visual or auditory feedback is given to the user in realtime, of which a BCI mouse is a good example.
There are many techniques for obtaining electrical information from the brain. One might use the frequency spectrum, spectral power, amplitudes or actual patterns of acquired signals.
Some BCI applications might require the user to realize an action, such as lifting a finger or rolling an eye, while some others just require the user to think doing so.
