Portable EEG vice design and applications

Electroencephalography (EEG) signals are small amplitude and low frequency electrical signals received from the brain through electrodes placed on the skull. EEG signals can be easily affected by external factors. For this reason, they must be subjected to various pre-processes during their examination. EEG signals are frequently used to obtain information about brain structure and thought patterns. It is possible to make some predictions and determinations as a result of examining the EEG signals that change according to environmental effects, hereditary or subsequent disorders. Within the scope of this thesis, a series of studies have been carried out on the collection, hardware processing, recording, software processing and classification of EEG signals. Research has been done on the hardware equipment required for the collection of EEG signals and an instrumentation amplifier has been designed as a result of these researches. The produced amplifier and some of the similar quality amplifiers and fully equipped EEG recorders available in the market were compared. At the end of the studies, a portable EEG recorder was designed. The designed device transmits the signals to the instrumentation amplifier with disposable electrodes containing silver/silver chloride (Ag/AgCl), and sends them to the computer via a wireless transmitter after a series of hardware processes. The desktop application developed for the designed hardware receives the signals and processes them in software, and performs the classification of some facial expressions. Several classification methods have been tested on the collected signals and the most efficient algorithm in the comparison results has been added to the application.