Hearing loss is a global public health issue due to its high prevalence and negative impact on various aspects of one’s life, including well being and cognition. Despite their crucial role in auditory rehabilitation, hearing aids remain inaccessible to many due to their high costs, particularly in low- and middle-income countries. Existing open-source solutions often rely on high-power, bulky platforms rather than compact, low-power wearables suited for real-world applications. This work introduces Tiresias, an open-source hearing aid development board designed for real-time audio processing using low-cost electronics. Integrating key hearing aid functionalities into a compact six-layer printed circuit board (PCB), Tiresias features multichannel compression, digital filtering, beamforming, Bluetooth connectivity, and physiological data monitoring, fostering modularity and accessibility through publicly available hardware and firmware resources based on the Nordic nRF Connect and Zephyr real-time operating system (RTOS). By addressing technological and accessibility challenges, this work advances open-source hearing aid development, enabling research in hearing technologies, while also supporting future refinements and real-world validation.
