The design and development of cost effective rehabilitation aids is a challenging task for biomedical research community. The biopotentials such as EEG, EMG, ECG and EOG that are generated from human body help in controlling the external electronic devices. In the recent years, the EOG based assistive devices have gained importance in assisting paralyzed patients, due to their ability to perform operations controlled by retinal movements. This paper proposes a cost effective design and development of EOG signal acquisition system using virtual instrumentation. The hardware design comprises of two instrumentation amplifiers using AD620 for registering horizontal and vertical eye movements and filter circuits. A virtual instrumentation based front panel is designed to interface the hardware and to display the EOG signals. The resultant digitized EOG signal is further enhanced for driving assistive devices. The proposed EOG system makes use of virtual instrumentation and hence minimizes the design cost and increases the flexibility of the instrument. This paper presents the initial part of the research work which is aiming at a cost effective complete assistive device based on extracting the useful information from the eye movements. The qualitative validation of EOG signals recorded ensures the cost effective healthcare delivery for rehabilitation applications.
Design and development of an assistive device for the visually impaired