A portable wireless eye movement-controlled Human-Computer Interface for the Disabled

Human-Computer Interface (HCI) has become an important area of research and development for the disabled. A portable wireless eye movement-controlled Human-Computer Interface which can be used for the disabled who have motor paralysis and who cannot speak in multiple applications (such as communication aid and smart home applications) is described here. This Interface consists of four major parts: (1) surface electrodes, (2) a two-channel amplifier, (3) a laptop (or a micro-processor), and (4) a ZigBee wireless module. Horizontal and vertical Electro-Oculography (EOG) signals are measured using five surface electrodes placed on the head The vertical electrodes are placed about 1.0 cm above the right eyebrow and 2.0 cm below the lower lid of the right eye, the horizontal electrodes are placed 2.0 cm lateral to the each side of outer canthi and the last electrode is placed on user's forehead to serve as a ground. The two-channel amplifier is comprised of instrumentation amplifiers, band-pass filters and shift circuits. The EOG signals are sampled at the rate of 250Hz and then sent to a laptop or a micro-processor for signal processing which is based on the method of mathematical morphology to recognize the direction of eye movements and voluntary eye blink. The ZigBee wireless communication technology, which is proved to be reliable, low-power and cost-efficient, is used in the portable interface. The subjects can control the wireless device or move a cursor over a screen by using this interface. The delay of this interface is less than 0.5s and errors are very limited. This interface provides a flexible method for the disabled to improve the life quality.