Engineers at Northwestern University have developed GlassTENG, smart glasses that operate without a battery. The device is powered by facial movements, including blinking, smiling, clenching jaws, and raising eyebrows.
The system utilizes three triboelectric nanogenerators (TENG) placed on the bridge of the nose, the temple, and near the ear. These sensors convert mechanical energy from facial skin contact into electrical charges, generating between 50 mV and 1.5 V depending on the activity.
The device monitors health metrics such as heart rate and facial muscle activity. Data is transmitted via Bluetooth to external devices, though developers aim to achieve full system autonomy in the future.
Testing with 20 volunteers showed a 93.8% accuracy rate in identifying facial actions. Specifically, teeth grinding was recognized with 99% accuracy and jaw clenching with 96%. Heart rate monitoring showed an average error of 1.82 beats per minute compared to chest sensors.
The current prototype faces challenges in distinguishing between speech and eating, as both activities engage similar facial muscles. Speech recognition accuracy reached 55%, while 37% of speech instances were incorrectly identified as eating.
