Respiration-Driven Closed-Loop Modulation of Binaural Beats

Binaural beats (BB) have gained attention for their potential to entertain brainwave activity to favor relaxation. Current research on BB typically employs a static frequency difference (Δf), which may limit their adaptability to individual physiological states. Furthermore, existing systems do not incorporate real-time biosignals, thereby missing the opportunity to align auditory stimulation with the body’s own dynamic physiological rhythms. This work presents a closed-loop system for real-time modulation of binaural beats based on respiratory activity. Unlike conventional approaches, the proposed method continuously adjusts the Δf according to the user's real-time respiratory biosignal. This design is motivated by the established role of breath control in the sympathovagal balance, relevant for relaxation and meditative practices. The system aims to enhance the effectiveness of BB through physiological alignment. Respiratory activity is acquired via a chest belt sensor and linearly mapped to a Δf range of 4–10 Hz, corresponding to relaxationrelated brainwave frequencies in electroencephalography. The system has been implemented on a custom embedded platform, enabling low-latency signal processing and stable audio output. 10-minute functional pre-tests were conducted involving five healthy participants, and the results validated the proposed operational concept.