Researchers at the University of Osaka have developed a wireless EEG transmission system that runs using body heat, showing that wearable brain-monitoring devices may one day work without batteries.

The team demonstrated the system outdoors in summer conditions above 89.6°F, where it continued operating by harvesting energy from the temperature difference between the human body and the surrounding air. No external power source or airflow was required in the process.

The EEG systems track electrical activity in the brain and are often used for long-term monitoring in healthcare and research. But wireless versions can consume significant power over time, creating limits around battery life, maintenance, and practicality.

The Osaka researchers addressed that challenge by designing a low-power architecture that reduces how much data must be captured and transmitted, helping the device run on tiny amounts of harvested energy.

Less data, more

Instead of continuously sending full EEG signals, the system randomly undersamples the brainwave data. A receiver-side algorithm then reconstructs the original signal from the smaller dataset. This lowers energy demand while maintaining usable signal quality, making battery-free wireless EEG transmission possible.

“Our long-term goal is to create sensing systems that can operate indefinitely without maintenance,” says lead author Daisuke Kanemoto. “A wireless EEG transmission system without any external power source is an important step toward practical, maintenance-free sensing technologies.”

The researchers also tested the device in a real-world environment during Expo 2025 in Osaka. Even in hot outdoor weather, the system kept working despite the smaller temperature gap between skin and air. That is notable because thermoelectric systems typically generate less power when the surrounding temperatures rise closer to body temperature.

Summer test succeeds

“Although the amount of harvestable energy decreases as the outside temperature approaches that of the human body, our results show that continuous wireless EEG transmission is possible even when the temperature difference is only a few degrees.” The team said the result suggests such systems can function beyond lab settings and in real operating environments.

Future uses could include wearable health monitors, long-duration medical sensors, and maintenance-free electronics that need little or no battery replacement. The same approach may also help power sensors used in infrastructure monitoring, environmental tracking, and smart-city networks, where changing batteries across thousands of devices can be costly and difficult.

As low-power electronics improve, devices that run on small amounts of ambient energy could become more common. Body heat, vibrations, light, and other everyday sources may support a new class of self-powered sensors.

For healthcare, the idea is especially relevant. Continuous brain monitoring without battery charging or replacement could make EEG wearables easier to use for patients over long periods. If scaled further, the Osaka team’s work points to a future where some medical and connected devices quietly power themselves using energy already available in the environment.

The study was published in the Proceedings of the IEEE International Conference on Consumer Electronics.