Our actions are thought in the brain, and the movement is implemented by the combination of neural transmission and muscle activation. Similarly, our sensing is perceived by us by our brain receiving the neural signals from our sensory organs. However, many people do not have functioning neural pathways or muscles that produce sufficient force. For such people, technology that connects the muscles or sensory organs directly with the brain is referred to as brain–computer interface (BCI). Such connectivity may be achieved using invasive or noninvasive methods.

This chapter describes the use of brain waves recorded by noninvasive and invasive techniques to produce an action command. In this chapter, the fundamentals of brain waves, the electroencephalogram or electroencephalography (EEG), and BCI are introduced. Subsequently, EEG recording and analysis technology is described and the methods for automatic identification of commands from EEG are discussed. This chapter also briefly explains sensory BCI devices.

Current technologies and implementation are then described along with the possible applications, user requirements, and limitations. In the end of this chapter, some of the major current and proposed research activities are discussed.