Electroencephalogram recording system

An electroencephalogram (EEG) instrument has been successfully developed and tested for recording, visual and aural indication, electrode contact testing and biofeedback using discrete components. The key idea is to identify the different brain waves (delta, theta, alpha, beta) with separate audio/visual indication on the front panel. As the EEG signal lies in the range of 0.5 to 100 Hz, a notch filter is designed to eliminate the 50 Hz supply frequency. The brainwaves can be observed on the CRO (cathode ray oscilloscope) screen. The biofeedback technique is implemented by identifying the brain waves from audio/visual indications. The instrument also helps in checking the proximity of electrode on the scalp. The instrument is designed to generate distinct audio alarms for different brain waves. The paper also focuses on computer interfacing for record of EEG patterns. The instrument provides alpha relaxation technique by announcing the present status of the brain