University of Osaka achieves battery-free EEG transmission powered by human body heat at Expo 2025

University of Osaka researchers demonstrate a wireless EEG system that harvests energy from body heat, operating reliably even in 32°C outdoor heat.

By: AXL Media

Published: Apr 28, 2026, 9:33 AM EDT

Source: Information for this report was sourced from EurekAlert!

Engineering a Sustainable Shift Toward Maintenance Free Health Monitoring

Researchers at the University of Osaka have achieved a significant milestone in wearable technology by developing a wireless EEG transmission system that requires no external batteries. By utilizing thermoelectric energy harvesting, the device captures the subtle temperature difference between human skin and the surrounding air to power its internal circuitry. This innovation addresses a primary hurdle in long term medical observation, where the power demands of continuous sensing often lead to heavy battery packs and frequent maintenance schedules that disrupt patient care.

Overcoming Thermal Equilibrium Challenges in High Temperature Environments

The efficiency of energy harvesting typically drops as the external environment nears the temperature of the human body, a major obstacle for heat based power sources. However, the team demonstrated their system’s resilience during a live trial at Expo 2025 in Osaka, where the device continued to transmit data in ambient temperatures exceeding 32°C. According to lead author Daisuke Kanemoto, the system remains reliable even when the thermal gap is only a few degrees, proving that such technologies are viable for real world applications beyond the stable conditions of a laboratory.

Data Reconstruction Strategies to Minimize Device Energy Consumption

To achieve such low power operation, the researchers implemented a specialized system architecture that prioritizes data efficiency over raw transmission volume. By randomly undersampling the EEG signals, the wearable hardware significantly reduces the amount of information it must process and send wirelessly. A sophisticated algorithm on the receiver side then reconstructs the original, complex brainwave signals with high accuracy, ensuring that the reduction in power does not result in a loss of medical data integrity.