For the understanding of the expressions and emotional state of the mentally retarded a basic circuit that has the ability of convert the brain waves received from the user into understandable and audible words in real time is designed.
This circuit basically identifies the received brainwaves into a series of four classified frequencies namely:DeltaThetaAlphaBeta (the frequency of these is within the ranges of0.1 - 3.2 Hz;3.2 - 7.8 Hz; 7.8 - 14 Hz; 14 - 30 Hz. respectively). From the above frequencies we screen the unstable and timidfrequencies (Delta and Theta) and account only for the reliable stable frequency (Alpha and Beta).
This acceptable frequency range is translated into electrical signals using a basic EEG circuit. The output of the EEG circuit is then translated into analog frequency that can be displayed as sonic vibrations of audible frequency so that it can be understood by other normal humans.
In actuality this circuit is much faster because it works at a nearer speed of the speed of thoughts and since there is no use of drugs or electrical shocks the patients has any need to suffer thus it is safer and reliable.