The electrooculogram (EOG) is captured by five electrodes placed around the eyes, as shown in Fig. 1(b). The EOG signals are obtained by placing two electrodes to the right and left of the outer canthi (D-E) to detect horizontal movement and another pair above and below the eye (B-C) to detect vertical movement. A reference electrode is placed on the forehead (A). The EOG signal changes approximately 20 microvolts for each degree of eye movement. In our system, the signals are sampled 10 times per second. The EOG signal is a result of a number of factors, including eyeball rotation and movement, eyelid movement, different sources of artifact such as EEG, electrode placement, head movements, influence of the illumination, etc. It is therefore necessary to eliminate the shifting resting potential (mean value) because this value changes. To avoid this problem an ac high-gain differential amplifier (1000–5000) is used, to- gether with a high pass filter with cutoff frequency at 0.05 Hz and relatively long time constant and a low pass filter with cutoff frequency at 35 Hz. Ag-AgCl floating metal body-surface electrodes are also used.