Development of a Digital Front-End for Electrooculography Circuits to Facilitate Digital Communication in Individuals with Communicative and Motor Disabilities

TL;DR

This paper presents a cost-effective digital front-end for electrooculography circuits designed to enable communication for individuals with severe motor disabilities, demonstrating real-time eye movement tracking with acceptable latency.

Contribution

The study introduces a novel, low-cost, digital-viable EOG front-end system using an Arduino and TL072 op-amp, with detailed design and performance analysis for assistive communication.

Findings

Achieved real-time eye movement tracking at 256 Hz sampling rate.

Latency measured around 20ms, suitable for communication applications.

Signal-to-noise ratio of 1.07 dB indicates noise interference challenges.

Abstract

This project developed a cost-effective, digital-viable front-end for electrooculography (EOG) circuits aimed at enabling communication for individuals with Locked-in Syndrome (LIS) and Amyotrophic Lateral Sclerosis (ALS). Using the TL072 operational amplifier, the system amplifies weak EOG signals and processes them through an Arduino Uno for real-time monitoring. The circuit includes preamplification, filtering between 0.1 Hz and 30 Hz, and final amplification stages, achieving accurate eye movement tracking with a 256 Hz sampling rate. The approach to this was described in detail, with a comparison drawn between the theoretical expectations of our circuit design and its viability in contrast to the actual values measured. Our readings aimed to create an interface that optimized max-gaze angle readings by outputting a maximum reading at values above the baseline theory of our amplification circuit. From this, we measured the latency between the serial output and action, analyzing video recordings of such readings. The Latency value read reached around 20ms, which is within the tolerance for proper communication and did not seriously affect the readings. Beyond this, challenges such as noise interference (with an SNR of 1.07 dB) remain despite achieving reliable signal amplification. This was during a test of the analog functionality of this circuit. However, its limitations mean that future improvements will focus on reducing environmental interference, optimizing electrode placement, applying a novel detection algorithm to optimize communication applications, and enhancing signal clarity to make the system more effective for real-world applications.