EOG analog front-end for human machine interface

Abstract

This paper describes the implementation of a two-channel analog front-end circuit for electrooculography signals. Due to hyper polarizations and depolarizations between the cornea and the retina, the human eye can be modeled as an electric dipole. An analog signal conditioning circuit has been proposed to capture the electric dipole potential and the saccadic eye movements, by using high precision instrumentation amplifier and integrator circuit to adjust the offset. A right drive leg is implemented to increase the common mode rejection ratio along with a Butterworth low pass filter to eliminate the interference noise from power line sources. Also, it was implemented an isolator circuit to separate the bio-signals from the signals in a microcontroller (human-computer interface) as well as a mask for easy implementation and use to control a wheelchair.